HP FlexNetwork 7500 Configuration Manual

HPE FlexNetwork 7500 Switch Series

IP Multicast Configuration Guide

Part number: 5998-7469R Software version: 7500-CMW710-R7178 Document version: 6W100-20160129

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Acknowledgments

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Multicast overview ··························································································· 1

Introduction to multicast ····································································································································· 1

Information transmission techniques ·········································································································· 1 Multicast features ······································································································································· 3 Common notations in multicast ·················································································································· 4

Multicast benefits and applications ············································································································ 4 Multicast models ················································································································································ 4 Multicast architecture ········································································································································· 5

Multicast addresses ··································································································································· 5

Multicast protocols ····································································································································· 8 Multicast packet forwarding mechanism ·········································································································· 11

Configuring IGMP snooping ·········································································· 12

IGMP snooping ports ······························································································································· 12

How IGMP snooping works ······················································································································ 14

Protocols and standards ·························································································································· 15 General configuration restrictions and guidelines ···························································································· 15 IGMP snooping configuration task list ·············································································································· 16 Configuring basic IGMP snooping features ····································································································· 16

Enabling IGMP snooping ························································································································· 16

Specifying an IGMP snooping version ····································································································· 17

Setting the maximum number of IGMP snooping forwarding entries ······················································· 18

Setting the IGMP last member query interval ·························································································· 18 Configuring IGMP snooping port features ········································································································ 19

Setting aging timers for dynamic ports ····································································································· 19

Configuring static ports ···························································································································· 20

Configuring a port as a simulated member host ······················································································ 20

Enabling fast-leave processing ················································································································ 21

Disabling a port from becoming a dynamic router port ············································································ 21 Configuring the IGMP snooping querier ··········································································································· 22

Configuration prerequisites ······················································································································ 22

Enabling the IGMP snooping querier ······································································································· 22

Configuring parameters for IGMP general queries and responses ·························································· 23 Configuring parameters for IGMP messages ··································································································· 23

Configuration prerequisites ······················································································································ 24

Configuring source IP addresses for IGMP messages ············································································ 24

Setting the 802.1p priority for IGMP messages ······················································································· 25 Configuring IGMP snooping policies ················································································································ 25

Configuring a multicast group policy ········································································································ 25

Enabling multicast source port filtering ···································································································· 26

Enabling dropping unknown multicast data ······························································································ 27

Enabling IGMP report suppression ·········································································································· 27

Setting the maximum number of multicast groups on a port ···································································· 28

Enabling multicast group replacement ····································································································· 28 Displaying and maintaining IGMP snooping ···································································································· 29 IGMP snooping configuration examples ·········································································································· 30

Group policy and simulated joining configuration example ······································································ 30

Static port configuration example ············································································································· 32

IGMP snooping querier configuration example ························································································ 35 Troubleshooting IGMP snooping ····················································································································· 37

Layer 2 multicast forwarding cannot function ··························································································· 37

Multicast group policy does not work ······································································································· 38

Configuring PIM snooping ············································································· 39

Displaying and maintaining PIM snooping ······································································································· 41 PIM snooping configuration example ··············································································································· 41 Troubleshooting PIM snooping ························································································································ 45

PIM snooping does not work on a Layer 2 device ··················································································· 45

Configuring multicast VLANs ········································································ 46

Configuration prerequisites ······················································································································ 48

Configuration guidelines ··························································································································· 48

Configuration procedure ··························································································································· 48 Configuring a port-based multicast VLAN ········································································································ 49

Configuration prerequisites ······················································································································ 49

Configuring user port attributes ················································································································ 49

Assigning user ports to a multicast VLAN ································································································ 50 Setting the maximum number of multicast VLAN forwarding entries ······························································· 50 Displaying and maintaining multicast VLANs ··································································································· 51 Multicast VLAN configuration examples ·········································································································· 51

Sub-VLAN-based multicast VLAN configuration example ······································································· 51

Port-based multicast VLAN configuration example ·················································································· 54

Configuring multicast routing and forwarding ················································ 58

RPF check mechanism ···························································································································· 58

Static multicast routes ······························································································································ 60

Multicast forwarding across unicast subnets ···························································································· 61 Configuration task list ······································································································································· 62 Enabling IP multicast routing ··························································································································· 62 Configuring multicast routing and forwarding ··································································································· 62

Configuring static multicast routes ··········································································································· 62

Specifying the longest prefix match principle ··························································································· 63

Configuring multicast load splitting ··········································································································· 63

Configuring a multicast forwarding boundary ··························································································· 64

Configuring static multicast MAC address entries ···················································································· 64 Enabling multicast forwarding between sub-VLANs of a super VLAN ····························································· 65 Displaying and maintaining multicast routing and forwarding ·········································································· 65 Multicast routing and forwarding configuration examples ················································································ 67

Changing an RPF route ··························································································································· 67

Creating an RPF route ····························································································································· 69

Multicast forwarding over a GRE tunnel ··································································································· 71 Troubleshooting multicast routing and forwarding ··························································································· 73

Static multicast route failure ····················································································································· 73

Configuring IGMP ························································································· 75

IGMPv1 overview ····································································································································· 75

IGMPv2 enhancements ···························································································································· 76

IGMPv3 enhancements ···························································································································· 77

IGMP SSM mapping ································································································································ 78

IGMP support for VPNs ···························································································································· 79

Protocols and standards ·························································································································· 79 IGMP configuration task list ····························································································································· 80 Configuring basic IGMP features ····················································································································· 80

Enabling IGMP ········································································································································· 80

Specifying an IGMP version ····················································································································· 81

Configuring a static group member ·········································································································· 81

Configuring a multicast group policy ········································································································ 81 Adjusting IGMP performance ··························································································································· 82

Configuring IGMP query and response parameters ················································································· 82

Enabling fast-leave processing ················································································································ 84 Enabling IGMP NSR ········································································································································ 85

Configuring IGMP SSM mappings ··················································································································· 85

Configuration prerequisites ······················································································································ 85

Configuration procedure ··························································································································· 85 Displaying and maintaining IGMP ···················································································································· 85 IGMP configuration examples ·························································································································· 86

Basic IGMP features configuration examples ·························································································· 86

IGMP SSM mapping configuration example ···························································································· 88 Troubleshooting IGMP ····································································································································· 91

No membership information on the receiver-side router ·········································································· 91

Inconsistent membership information on the routers on the same subnet ··············································· 92

Configuring PIM ···························································································· 94

PIM-DM overview ····································································································································· 94

PIM-SM overview ····································································································································· 96

BIDIR-PIM overview ······························································································································· 100

Administrative scoping overview ············································································································ 103

PIM-SSM overview ································································································································· 105

Relationship among PIM protocols ········································································································ 106

PIM support for VPNs ···························································································································· 107

Protocols and standards ························································································································ 107 Configuring PIM-DM ······································································································································ 107

PIM-DM configuration task list ··············································································································· 108

Configuration prerequisites ···················································································································· 108

Enabling PIM-DM ··································································································································· 108

Enabling the state refresh feature ·········································································································· 108

Configuring state refresh parameters ····································································································· 109

Configuring PIM-DM graft retry timer ····································································································· 109 Configuring PIM-SM ······································································································································· 110

PIM-SM configuration task list ················································································································ 110

Configuration prerequisites ···················································································································· 110

Enabling PIM-SM ··································································································································· 110

Configuring an RP ·································································································································· 111

Configuring a BSR ································································································································· 112

Configuring multicast source registration ······························································································· 114

Configuring the switchover to SPT ········································································································· 115 Configuring BIDIR-PIM ·································································································································· 115

Configuration restrictions and guidelines ······························································································· 115

BIDIR-PIM configuration task list ··········································································································· 115

Configuration prerequisites ···················································································································· 116

Enabling BIDIR-PIM ······························································································································· 116

Configuring an RP ·································································································································· 117

Configuring a BSR ································································································································· 118 Configuring PIM-SSM ···································································································································· 120

PIM-SSM configuration task list ············································································································· 120

Configuration prerequisites ···················································································································· 120

Enabling PIM-SM ··································································································································· 121

Configuring the SSM group range ·········································································································· 121 Configuring common PIM features ················································································································ 122

Configuration task list ····························································································································· 122

Configuration prerequisites ···················································································································· 122

Configuring a multicast source policy ····································································································· 122

Configuring a PIM hello policy ················································································································ 122

Configuring PIM hello message options ································································································· 123

Configuring common PIM timers ············································································································ 124

Setting the maximum size of each join or prune message ····································································· 126

Enabling BFD for PIM ···························································································································· 126

Enabling PIM passive mode ··················································································································· 126

Enabling PIM NSR ································································································································· 127 Displaying and maintaining PIM ····················································································································· 127 PIM configuration examples ··························································································································· 128

PIM-DM configuration example ·············································································································· 128

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PIM-SM non-scoped zone configuration example ················································································· 131

PIM-SM admin-scoped zone configuration example ·············································································· 134

BIDIR-PIM configuration example ·········································································································· 139

PIM-SSM configuration example ············································································································ 143 Troubleshooting PIM ······································································································································ 146

A multicast distribution tree cannot be correctly built ············································································· 146

Multicast data is abnormally terminated on an intermediate router ························································ 147

An RP cannot join an SPT in PIM-SM ···································································································· 147

An RPT cannot be built or multicast source registration fails in PIM-SM ··············································· 147

Configuring MSDP ······················································································ 149

How MSDP works ·································································································································· 149

MSDP support for VPNs ························································································································ 154

Protocols and standards ························································································································ 154 MSDP configuration task list ·························································································································· 155 Configuring basic MSDP features ·················································································································· 155

Configuration prerequisites ···················································································································· 155

Enabling MSDP ······································································································································ 155

Specifying an MSDP peer ······················································································································ 156

Configuring a static RPF peer ················································································································ 156 Configuring an MSDP peering connection ····································································································· 156

Configuration prerequisites ···················································································································· 157

Configuring a description for an MSDP peer ·························································································· 157

Configuring an MSDP mesh group ········································································································ 157

Controlling MSDP peering connections ································································································· 157 Configuring SA message-related parameters ································································································ 158

Configuration prerequisites ···················································································································· 158

Enabling multicast data encapsulation in SA messages ········································································ 159

Configuring the originating RP of SA messages ···················································································· 159

Configuring SA request messages ········································································································· 159

Configuring SA message policies ·········································································································· 160

Configuring the SA cache mechanism ··································································································· 161 Displaying and maintaining MSDP ················································································································· 161 MSDP configuration examples ······················································································································· 162

PIM-SM inter-domain multicast configuration ························································································ 162

Inter-AS multicast configuration by leveraging static RPF peers ··························································· 167

Anycast RP configuration ······················································································································· 171

SA message filtering configuration ········································································································· 175 Troubleshooting MSDP ·································································································································· 178

MSDP peers stay in disabled state ········································································································ 178

No SA entries exist in the router's SA message cache ·········································································· 178

No exchange of locally registered (S, G) entries between RPs ····························································· 178

Configuring multicast VPN ·········································································· 180

MD VPN overview ·································································································································· 181

Protocols and standards ························································································································ 184 How MD VPN works······································································································································· 185

Default-MDT establishment ···················································································································· 185

Default-MDT-based delivery ·················································································································· 187

MDT switchover ····································································································································· 190

Inter-AS MD VPN ··································································································································· 191 Multicast VPN configuration task list ·············································································································· 193 Configuring MD VPN ······································································································································ 194

Configuration prerequisites ···················································································································· 194

Enabling IP multicast routing in a VPN instance ···················································································· 194

Creating an MD for a VPN instance ······································································································· 195

Specifying the default-group ·················································································································· 195

Specifying the MD source interface ······································································································· 195

Configuring MDT switchover parameters ······························································································· 196

Enabling data-group reuse logging ········································································································ 196

Configuring BGP MDT ··································································································································· 196

Configuration prerequisites ···················································································································· 197

Enabling BGP MDT peers or peer groups ····························································································· 197

Configuring a BGP MDT route reflector ································································································· 197 Displaying and maintaining multicast VPN ···································································································· 198 Multicast VPN configuration examples ·········································································································· 199

Intra-AS MD VPN configuration example ······························································································· 199

MD VPN inter-AS option C configuration example ················································································· 212 Troubleshooting MD VPN ······························································································································ 225

A default-MDT cannot be established ···································································································· 225

An MVRF cannot be created ·················································································································· 226

Configuring MLD snooping ········································································· 227

MLD snooping ports ······························································································································· 227

How MLD snooping works ····················································································································· 229

Protocols and standards ························································································································ 230 General configuration restrictions and guidelines ·························································································· 230 MLD snooping configuration task list ············································································································· 231 Configuring basic MLD snooping features ····································································································· 231

Enabling MLD snooping ························································································································· 231

Specifying an MLD snooping version ····································································································· 232

Setting the maximum number of MLD snooping forwarding entries ······················································ 233

Setting the MLD last listener query interval ···························································································· 233 Configuring MLD snooping port features ······································································································· 234

Setting aging timers for dynamic ports ··································································································· 234

Configuring static ports ·························································································································· 235

Configuring a port as a simulated member host ···················································································· 235

Enabling fast-leave processing ·············································································································· 236

Disabling a port from becoming a dynamic router port ·········································································· 237 Configuring the MLD snooping querier ·········································································································· 237

Configuration prerequisites ···················································································································· 237

Enabling the MLD snooping querier ······································································································· 237

Configuring parameters for MLD general queries and responses ························································· 238 Configuring parameters for MLD messages ·································································································· 239

Configuration prerequisites ···················································································································· 239

Configuring source IPv6 addresses for MLD messages ········································································ 239

Setting the 802.1p priority for MLD messages ······················································································· 240 Configuring MLD snooping policies ··············································································································· 241

Configuring an IPv6 multicast group policy ···························································································· 241

Enabling IPv6 multicast source port filtering ·························································································· 242

Enabling dropping unknown IPv6 multicast data ··················································································· 242

Enabling MLD report suppression ·········································································································· 243

Setting the maximum number of IPv6 multicast groups on a port ·························································· 243

Enabling IPv6 multicast group replacement ··························································································· 244 Displaying and maintaining MLD snooping ···································································································· 244 MLD snooping configuration examples ·········································································································· 246

IPv6 group policy and simulated joining configuration example ····························································· 246

Static port configuration example ··········································································································· 248

MLD snooping querier configuration example ························································································ 251 Troubleshooting MLD snooping ····················································································································· 253

Layer 2 multicast forwarding cannot function ························································································· 253

IPv6 multicast group policy does not work ····························································································· 253

Configuring IPv6 PIM snooping ·································································· 255

Overview ························································································································································ 255 Configuring IPv6 PIM snooping ····················································································································· 256 Displaying and maintaining IPv6 PIM snooping ····························································································· 257 IPv6 PIM snooping configuration example ····································································································· 257 Troubleshooting IPv6 PIM snooping ·············································································································· 261

IPv6 PIM snooping does not work on a Layer 2 device ········································································· 261

Configuring IPv6 multicast VLANs ······························································ 262

Configuration prerequisites ···················································································································· 264

Configuration guidelines ························································································································· 264

Configuration procedure ························································································································· 264 Configuring a port-based IPv6 multicast VLAN ······························································································ 265

Configuration prerequisites ···················································································································· 265

Configuring user port attributes ·············································································································· 265

Assigning user ports to an IPv6 multicast VLAN ···················································································· 266 Setting the maximum number of IPv6 multicast VLAN forwarding entries ····················································· 266 Displaying and maintaining IPv6 multicast VLANs ························································································ 267 IPv6 multicast VLAN configuration examples ································································································ 267

Sub-VLAN-based IPv6 multicast VLAN configuration example ····························································· 267

Port-based IPv6 multicast VLAN configuration example ········································································ 270

Configuring IPv6 multicast routing and forwarding ······································ 274

RPF check mechanism ·························································································································· 274

IPv6 multicast forwarding across IPv6 unicast subnets ········································································· 276 Configuration task list ····································································································································· 276 Enabling IPv6 multicast routing ······················································································································ 276 Configuring IPv6 multicast routing and forwarding ························································································ 277

Specifying the longest prefix match principle ························································································· 277

Configuring IPv6 multicast load splitting ································································································ 277

Configuring an IPv6 multicast forwarding boundary ··············································································· 278

Configuring IPv6 static multicast MAC address entries ········································································· 278

Enabling IPv6 multicast forwarding between sub-VLANs of a super VLAN ··········································· 279 Displaying and maintaining IPv6 multicast routing and forwarding ································································ 279 IPv6 multicast forwarding over a GRE tunnel configuration example ···························································· 281

Network requirements ···························································································································· 281

Configuration procedure ························································································································· 281

Verifying the configuration ······················································································································ 283

Configuring MLD ························································································· 284

How MLDv1 works ································································································································· 284

MLDv2 enhancements ··························································································································· 286

MLD SSM mapping ································································································································ 287

MLD support for VPNs ··························································································································· 288

Protocols and standards ························································································································ 288 MLD configuration task list ····························································································································· 288 Configuring basic MLD features ····················································································································· 288

Enabling MLD ········································································································································· 288

Specifying an MLD version ···················································································································· 289

Configuring a static group member ········································································································ 289

Configuring an IPv6 multicast group policy ···························································································· 290 Adjusting MLD performance ·························································································································· 290

Configuring MLD query and response parameters ················································································ 290

Enabling fast-leave processing ·············································································································· 292 Enabling MLD NSR ········································································································································ 292 Configuring MLD SSM mappings ··················································································································· 293

Configuration prerequisites ···················································································································· 293

Configuration procedure ························································································································· 293 Displaying and maintaining MLD ··················································································································· 293 MLD configuration examples ························································································································· 294

Basic MLD features configuration example ···························································································· 294

MLD SSM mapping configuration example ···························································································· 296 Troubleshooting MLD ····································································································································· 299

No member information exists on the receiver-side router ···································································· 299

Inconsistent membership information on the routers on the same subnet ············································· 300

Configuring IPv6 PIM ·················································································· 301

IPv6 PIM-DM overview ··························································································································· 301

IPv6 PIM-SM overview ··························································································································· 303

IPv6 BIDIR-PIM overview ······················································································································· 308

IPv6 administrative scoping overview ···································································································· 311

IPv6 PIM-SSM overview ························································································································ 313

Relationship among IPv6 PIM protocols ································································································ 314

IPv6 PIM support for VPNs ···················································································································· 315

Protocols and standards ························································································································ 315 Configuring IPv6 PIM-DM ······························································································································ 315

IPv6 PIM-DM configuration task list ······································································································· 316

Configuration prerequisites ···················································································································· 316

Enabling IPv6 PIM-DM ··························································································································· 316

Enabling the state refresh feature ·········································································································· 316

Configuring state refresh parameters ····································································································· 317

Configuring IPv6 PIM-DM graft retry timer ····························································································· 317 Configuring IPv6 PIM-SM ······························································································································ 318

IPv6 PIM-SM configuration task list ······································································································· 318

Configuration prerequisites ···················································································································· 318

Enabling IPv6 PIM-SM ··························································································································· 318

Configuring an RP ·································································································································· 319

Configuring a BSR ································································································································· 320

Configuring IPv6 multicast source registration ······················································································· 322

Configuring the switchover to SPT ········································································································· 322 Configuring IPv6 BIDIR-PIM ·························································································································· 323

Configuration restrictions and guidelines ······························································································· 323

IPv6 BIDIR-PIM configuration task list ··································································································· 323

Configuration prerequisites ···················································································································· 323

Enabling IPv6 BIDIR-PIM ······················································································································· 323

Configuring an RP ·································································································································· 324

Configuring a BSR ································································································································· 326 Configuring IPv6 PIM-SSM ···························································································································· 327

IPv6 PIM-SSM configuration task list ····································································································· 328

Configuration prerequisites ···················································································································· 328

Enabling IPv6 PIM-SM ··························································································································· 328

Configuring the IPv6 SSM group range ································································································· 328 Configuring common IPv6 PIM features ········································································································ 329

Configuration task list ····························································································································· 329

Configuration prerequisites ···················································································································· 329

Configuring an IPv6 multicast source policy ·························································································· 329

Configuring an IPv6 PIM hello policy ····································································································· 330

Configuring IPv6 PIM hello message options ························································································ 330

Configuring common IPv6 PIM timers ···································································································· 332

Setting the maximum size of each join or prune message ····································································· 333

Enabling BFD for IPv6 PIM ···················································································································· 333

Enabling IPv6 PIM passive mode ·········································································································· 334

Enabling IPv6 PIM NSR ························································································································· 334 Displaying and maintaining IPv6 PIM ············································································································ 335 IPv6 PIM configuration examples ·················································································································· 335

IPv6 PIM-DM configuration example ······································································································ 335

IPv6 PIM-SM non-scoped zone configuration example ········································································· 338

IPv6 PIM-SM admin-scoped zone configuration example ····································································· 341

IPv6 BIDIR-PIM configuration example ·································································································· 347

IPv6 PIM-SSM configuration example ··································································································· 351 Troubleshooting IPv6 PIM ······························································································································ 354

A multicast distribution tree cannot be correctly built ············································································· 354

IPv6 multicast data is abnormally terminated on an intermediate router ··············································· 354

An RP cannot join an SPT in IPv6 PIM-SM ··························································································· 355

An RPT cannot be built or IPv6 multicast source registration fails in IPv6 PIM-SM ······························· 355

vii

Document conventions and icons ······························································· 356

Conventions ··················································································································································· 356 Network topology icons ·································································································································· 357

Support and other resources ······································································ 358

Accessing Hewlett Packard Enterprise Support ···························································································· 358 Accessing updates ········································································································································· 358

Websites ················································································································································ 359

Customer self repair ······························································································································· 359

Remote support ······································································································································ 359

Documentation feedback ······················································································································· 359

Index ··········································································································· 361

viii

Multicast overview

Introduction to multicast

As a technique that coexists with unicast and broadcast, the multicast technique effectively addresses the issue of point-to-multipoint data transmission. By enabling high-efficiency point-to-multipoint data transmission over a network, multicast greatly saves network bandwidth and reduces network load.

By using multicast technology, a network operator can easily provide bandwidth-critical and time-critical information services. These services include live webcasting, Web TV, distance learning, telemedicine, Web radio, and real-time video conferencing.

Information transmission techniques

The information transmission techniques include unicast, broadcast, and multicast.

Unicast

In unicast transmission, the information source must send a separate copy of information to each host that needs the information.

Figure 1 Unicast transmission

Host A

Receiver

Host B

Source

Host C

Receiver

Host D

IP network

Packets for Host B

Packets for Host D

Packets for Host E

In Figure 1, Host B, Host D, and Host E need the information. A separate transmission channel must be established from the information source to each of these hosts.

Receiver

Host E

In unicast transmission, the traffic transmitted over the network is proportional to the number of hosts that need the information. If a large number of hosts need the information, the information source must send a separate copy of the same information to each of these hosts. Sending many copies can place a tremendous pressure on the information source and the network bandwidth.

Unicast is not suitable for batch transmission of information.

Broadcast

In broadcast transmission, the information source sends information to all hosts on the subnet, even if some hosts do not need the information.

Figure 2 Broadcast transmission

Multicast

In Figure 2, only Host B, Host D, and Host E need the information. If the information is broadcast to the subnet, Host A and Host C also receive it. In addition to information security issues, broadcasting to hosts that do not need the information also causes traffic flooding on the same subnet.

Broadcast is disadvantageous in transmitting data to specific hosts. Moreover, broadcast transmission is a significant waste of network resources.

Multicast provides point-to-multipoint data transmissions with the minimum network consumption. When some hosts on the network need multicast information, the information sender, or multicast source, sends only one copy of the information. Multicast distribution trees are built through multicast routing protocols, and the packets are replicated only on nodes where the trees branch.

Figure 3 Multicast transmission

The multicast source sends only one copy of the information to a multicast group. Host B, Host D, and Host E, which are information receivers, must join the multicast group. The routers on the network duplicate and forward the information based on the distribution of the group members. Finally, the information is correctly delivered to Host B, Host D, and Host E.

To summarize, multicast has the following advantages:

• Advantages over unicast—Multicast data is replicated and distributed until it flows to the

farthest-possible node from the source. The increase of receiver hosts will not remarkably increase the load of the source or the usage of network resources.

• Advantages over broadcast—Multicast data is sent only to the receivers that need it. This

saves network bandwidth and enhances network security. In addition, multicast data is not confined to the same subnet.

Multicast features

• A multicast group is a multicast receiver set identified by an IP multicast address. Hosts must

join a multicast group to become members of the multicast group before they receive the multicast data addressed to that multicast group. Typically, a multicast source does not need to join a multicast group.

• A multicast source is an information sender. It can send data to multiple multicast groups at the

same time. Multiple multicast sources can send data to the same multicast group at the same time.

• The group memberships are dynamic. Hosts can join or leave multicast groups at any time.

Multicast groups are not subject to geographic restrictions.

• Multicast routers or Layer 3 multicast devices are routers or Layer 3 switches that support Layer

3 multicast. They provide multicast routing and manage multicast group memberships on stub subnets with attached group members. A multicast router itself can be a multicast group member.

For a better understanding of the multicast concept, you can compare multicast transmission to the transmission of TV programs.

Table 1 Comparing TV program transmission and multicast transmission

TV program transmission Multicast transmission

A TV station transmits a TV program through a channel.

A user tunes the TV set to the channel. A receiver joins the multicast group.

The user starts to watch the TV program transmitted by the TV station on the channel.

The user turns off the TV set or tunes to another channel.

Common notations in multicast

The following notations are commonly used in multicast transmission:

• (*, G)—Rendezvous point tree (RPT), or a multicast packet that any multicast source sends to

multicast group G. The asterisk (*) represents any multicast source, and "G" represents a specific multicast group.

• (S, G)—Shortest path tree (SPT), or a multicast packet that multicast source "S" sends to

multicast group "G." "S" represents a specific multicast source, and "G" represents a specific multicast group.

For more information about the concepts RPT and SPT, see "Configuring PIM" and "Configuring

IPv6 PIM."

A multicast source sends multicast data to a multicast group.

The receiver starts to receive the multicast data sent by the source to the multicast group.

The receiver leaves the multicast group or joins another group.

Multicast benefits and applications

Multicast benefits

• Enhanced efficiency—Reduces the processor load of information source servers and network

devices.

• Optimal performance—Reduces redundant traffic.

• Distributed application—Enables point-to-multipoint applications at the price of minimum

network resources.

Multicast applications

• Multimedia and streaming applications, such as Web TV, Web radio, and real-time video/audio

conferencing

• Communication for training and cooperative operations, such as distance learning and

telemedicine

• Data warehouse and financial applications (stock quotes)

• Any other point-to-multipoint application for data distribution

Multicast models

Based on how the receivers treat the multicast sources, the multicast models include any-source multicast (ASM), source-filtered multicast (SFM), and source-specific multicast (SSM).

ASM model

In the ASM model, any multicast sources can send information to a multicast group. Receivers can join a multicast group and get multicast information addressed to that multicast group from any multicast sources. In this model, receivers do not know the positions of the multicast sources in advance.

SFM model

The SFM model is derived from the ASM model. To a multicast source, the two models appear to have the same multicast membership architecture.

The SFM model functionally extends the ASM model. The upper-layer software checks the source address of received multicast packets and permits or denies multicast traffic from specific sources. The receivers obtain the multicast data from only part of the multicast sources. To a receiver, multicast sources are not all valid, but are filtered.

SSM model

The SSM model provides a transmission service that enables multicast receivers to specify the multicast sources in which they are interested.

In the SSM model, receivers have already determined the locations of the multicast sources. This is the main difference between the SSM model and the ASM model. In addition, the SSM model uses a different multicast address range than the ASM/SFM model. Dedicated multicast forwarding paths are established between receivers and the specified multicast sources.

Multicast architecture

IP multicast addresses the following issues:

• Where should the multicast source transmit information to? (Multicast addressing.)

• What receivers exist on the network? (Host registration.)

• Where is the multicast source that will provide data to the receivers? (Multicast source

discovery.)

• How is the information transmitted to the receivers? (Multicast routing.)

IP multicast is an end-to-end service. The multicast architecture involves the following parts:

• Addressing mechanism—A multicast source sends information to a group of receivers

through a multicast address.

• Host registration—Receiver hosts can join and leave multicast groups dynamically. This

mechanism is the basis for management of group memberships.

• Multicast routing—A multicast distribution tree (a forwarding path tree for multicast data on the

network) is constructed for delivering multicast data from a multicast source to receivers.

• Multicast applications—A software system that supports multicast applications, such as video

conferencing, must be installed on multicast sources and receiver hosts. The TCP/IP stack must support reception and transmission of multicast data.

Multicast addresses

IP multicast addresses

• IPv4 multicast addresses:

IANA assigned the Class D address block (224.0.0.0 to 239.255.255.255) to IPv4 multicast.

Table 2 Class D IP address blocks and description

Address block Description

Reserved permanent group addresses. The IP address

224.0.0.0 is reserved. Other IP addresses can be used by routing protocols and for topology searching, protocol

224.0.0.0 to 224.0.0.255

224.0.1.0 to 238.255.255.255

239.0.0.0 to 239.255.255.255

NOTE:

maintenance, and so on. Table 3 lists comm group addresses. A packet destined for an address in this block will not be forwarded beyond the local subnet regardless of the TTL value in the IP header.

Globally scoped group addresses. This block includes the following types of designated group addresses:

• 232.0.0.0/8—SSM group addresses.

• 233.0.0.0/8—Glop group addresses.

Administratively scoped multicast addresses. These addresses are considered locally unique rather than globally unique. You can reuse them in domains administered by different organizations without causing conflicts. For more information, see RFC 2365.

on permanent

Glop is a mechanism for assigning multicast addresses between different ASs. By filling an AS number into the middle two bytes of 233.0.0.0, you get 255 multicast addresses for that AS. Fo more information, see RFC 2770.

Table 3 Common permanent multicast group addresses

Address Description

224.0.0.1 All systems on this subnet, including hosts and routers.

224.0.0.2 All multicast routers on this subnet.

224.0.0.3 Unassigned.

224.0.0.4 DVMRP routers.

224.0.0.5 OSPF routers.

224.0.0.6 OSPF designated routers and backup designated routers.

224.0.0.7 Shared Tree (ST) routers.

224.0.0.8 ST hosts.

224.0.0.9 RIPv2 routers.

224.0.0.11 Mobile agents.

224.0.0.12 DHCP server/relay agent.

224.0.0.13 All Protocol Independent Multicast (PIM) routers.

224.0.0.14 RSVP encapsulation.

224.0.0.15 All Core-Based Tree (CBT) routers.

224.0.0.16 Designated SBM.

224.0.0.17 All SBMs.

224.0.0.18 VRRP.

• IPv6 multicast addresses:

Figure 4 IPv6 multicast format

The following describes the fields of an IPv6 multicast address:

{ 0xFF—The most significant eight bits are 11111111. { Flags—The Flags field contains four bits.

Figure 5 Flags field format

Table 4 Flags field description

Bit Description

0 Reserved, set to 0.

• When set to 0, this address is an IPv6 multicast address without an embedded RP address.

• When set to 1, this address is an IPv6 multicast address with an embedded RP address. (The P and T bits must also be set to 1.)

• When set to 0, this address is an IPv6 multicast address not based on a unicast prefix.

• When set to 1, this address is an IPv6 multicast address based on a unicast prefix. (The T bit must also be set to 1.)

• When set to 0, this address is an IPv6 multicast

address permanently-assigned by IANA.

• When set to 1, this address is a transient, or dynamically assigned IPv6 multicast address.

Scope—The Scope field contains four bits, which represent the scope of the IPv6

{

internetwork for which the multicast traffic is intended.

Table 5 Values of the Scope field

Value Meaning

0, F Reserved.

1 Interface-local scope.

2 Link-local scope.

3 Subnet-local scope.

4 Admin-local scope.

5 Site-local scope.

6, 7, 9 through D Unassigned.

8 Organization-local scope.

Value Meaning

E Global scope.

{ Group ID—The Group ID field contains 112 bits. It uniquely identifies an IPv6 multicast

group in the scope that the Scope field defines.

Ethernet multicast MAC addresses

• IPv4 multicast MAC addresses:

As defined by IANA, the most significant 24 bits of an IPv4 multicast MAC address are 0x01005E. Bit 25 is 0, and the other 23 bits are the least significant 23 bits of an IPv4 multicast address.

Figure 6 IPv4-to-MAC address mapping

The most significant four bits of an IPv4 multicast address are fixed at 1110. In an IPv4-to-MAC address mapping, five bits of the IPv4 multicast address are lost. As a result, 32 IPv4 multicast addresses are mapped to the same IPv4 multicast MAC address. A device might receive unwanted multicast data at Layer 2 processing, which needs to be filtered by the upper layer.

• IPv6 multicast MAC addresses:

As defined by IANA, the most significant 16 bits of an IPv6 multicast MAC address are 0x3333. The least significant 32 bits are mapped from the least significant 32 bits of an IPv6 multicast address. Therefore, the problem of duplicate IPv6-to-MAC address mapping also arises like IPv4-to-MAC address mapping.

Figure 7 IPv6-to-MAC address mapping

Multicast protocols

Multicast protocols include the following categories:

• Layer 3 and Layer 2 multicast protocols:

{ Layer 3 multicast refers to IP multicast operating at the network layer.

Layer 3 multicast protocols—IGMP, MLD, PIM, IPv6 PIM, MSDP, MBGP, and IPv6

MBGP.

{ Layer 2 multicast refers to IP multicast operating at the data link layer.

Layer 2 multicast protocols—IGMP snooping, MLD snooping, PIM snooping, IPv6 PIM

snooping, multicast VLAN, and IPv6 multicast VLAN.

• IPv4 and IPv6 multicast protocols:

{ For IPv4 networks—IGMP snooping, PIM snooping, multicast VLAN, IGMP, PIM, MSDP,

and MBGP.

{ For IPv6 networks—MLD snooping, IPv6 PIM snooping, IPv6 multicast VLAN, MLD, IPv6

PIM, and IPv6 MBGP.

This section provides only general descriptions about applications and functions of the Layer 2 and Layer 3 multicast protocols in a network. For more information about these protocols, see the related chapters.

Layer 3 multicast protocols

Layer 3 multicast protocols include multicast group management protocols and multicast routing protocols.

Figure 8 Positions of Layer 3 multicast protocols

• Multicast group management protocols:

Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) protocol are multicast group management protocols. Typically, they run between hosts and Layer 3 multicast devices that directly connect to the hosts to establish and maintain multicast group memberships.

• Multicast routing protocols:

A multicast routing protocol runs on Layer 3 multicast devices to establish and maintain multicast routes and correctly and efficiently forward multicast packets. Multicast routes constitute loop-free data transmission paths (also known as multicast distribution trees) from a data source to multiple receivers.

In the ASM model, multicast routes include intra-domain routes and inter-domain routes.

{ An intra-domain multicast routing protocol discovers multicast sources and builds multicast

distribution trees within an AS to deliver multicast data to receivers. Among a variety of mature intra-domain multicast routing protocols, PIM is most widely used. Based on the forwarding mechanism, PIM has dense mode (often referred to as PIM-DM) and sparse mode (often referred to as PIM-SM).

{ An inter-domain multicast routing protocol is used for delivering multicast information

between two ASs. So far, mature solutions include Multicast Source Discovery Protocol (MSDP) and MBGP. MSDP propagates multicast source information among different ASs. MBGP is an extension of the MP-BGP for exchanging multicast routing information among different ASs.

For the SSM model, multicast routes are not divided into intra-domain routes and inter-domain routes. Because receivers know the positions of the multicast sources, channels established through PIM-SM are sufficient for the transport of multicast information.

Layer 2 multicast protocols

Layer 2 multicast protocols include IGMP snooping, MLD snooping, PIM snooping, IPv6 PIM snooping, multicast VLAN, and IPv6 multicast VLAN.

Figure 9 Positions of Layer 2 multicast protocols

• IGMP snooping and MLD snooping:

IGMP snooping and MLD snooping are multicast constraining mechanisms that run on Layer 2 devices. They manage and control multicast groups by monitoring and analyzing IGMP or MLD messages exchanged between the hosts and Layer 3 multicast devices. This effectively controls the flooding of multicast data in Layer 2 networks.

• PIM snooping and IPv6 PIM snooping:

PIM snooping and IPv6 PIM snooping run on Layer 2 devices. They work with IGMP snooping or MLD snooping to analyze received PIM messages. Then, they add the ports that are interested in specific multicast data to a PIM snooping routing entry or IPv6 PIM snooping routing entry. In this way, multicast data can be forwarded to only the ports that are interested in the data.

• Multicast VLAN and IPv6 multicast VLAN:

Multicast VLAN or IPv6 multicast VLAN runs on a Layer 2 device in a multicast network where multicast receivers for the same group exist in different VLANs. With these protocols, the Layer 3 multicast device sends only one copy of multicast to the multicast VLAN or IPv6 multicast VLAN on the Layer 2 device. This method avoids waste of network bandwidth and extra burden on the Layer 3 device.

Multicast packet forwarding mechanism

In a multicast model, receiver hosts of a multicast group are usually located at different areas on the network. They are identified by the same multicast group address. To deliver multicast packets to these receivers, a multicast source encapsulates the multicast data in an IP packet with the multicast group address as the destination address. Multicast routers on the forwarding paths forward multicast packets that an incoming interface receives through multiple outgoing interfaces. Compared to a unicast model, a multicast model is more complex in the following aspects:

• To ensure multicast packet transmission on the network, different routing tables are used to

guide multicast forwarding. These routing tables include unicast routing tables, routing tables for multicast (for example, the MBGP routing table), and static multicast routing tables.

• To process the same multicast information from different peers received on different interfaces,

the multicast device performs an RPF check on each multicast packet. The RPF check result determines whether the packet will be forwarded or discarded. The RPF check mechanism is the basis for most multicast routing protocols to implement multicast forwarding.

For more information about the RPF mechanism, see "Configuring multicast routing and

rding" and "Configuring IPv6 multicast routing and forwarding."

forwa

Configuring IGMP snooping

Overview

IGMP snooping runs on a Layer 2 device as a multicast constraining mechanism to improve multicast forwarding efficiency. It creates Layer 2 multicast forwarding entries from IGMP packets that are exchanged between the hosts and the router.

As shown in Figure 10, when IGMP packets to all hosts in a VLAN. When IGMP snooping is enabled, the Layer 2 switch forwards multicast packets of known multicast groups to only the receivers.

Figure 10 Multicast packet transmission without and with IGMP snooping

snooping is not enabled, the Layer 2 switch floods multicast

IGMP snooping ports

As shown in Figure 11, IGMP snooping runs on Switch A and Switch B, and Host A and Host C are receivers in a multicast group. IGMP snooping ports are divided into member ports and router ports.

Figure 11 IGMP snooping ports

Router ports

On an IGMP snooping Layer 2 device, the ports toward Layer 3 multicast devices are called router ports. In Figure 11, Gig router ports.

abitEthernet 1/0/1 of Switch A and GigabitEthernet 1/0/1 of Switch B are

Router ports contain the following types:

• Dynamic router port—When a port receives an IGMP general query whose source address is

not 0.0.0.0 or receives a PIM hello message, the port is added into the dynamic router port list. At the same time, an aging timer is started for the port. If the port receives either of the messages before the timer expires, the timer is reset. If the port does not receive either of the messages when the timer expires, the port is removed from the dynamic router port list.

• Static router port—When a port is statically configured as a router port, it is added into the

static router port list. The static router port does not age out, and it can be deleted only manually.

Do not confuse the "router port" in IGMP snooping with the "routed interface" commonly known as the "Layer 3 interface." The router port in IGMP snooping is a Layer 2 interface.

Member ports

On an IGMP snooping Layer 2 device, the ports toward receiver hosts are called member ports. In Figure 11, GigabitEthe of Switch B are member ports.

Member ports contain the following types:

• Dynamic member port—When a port receives an IGMP report, it is added to the associated

dynamic IGMP snooping forwarding entry as an outgoing interface. At the same time, an aging timer is started for the port. If the port receives an IGMP report before the timer expires, the timer is reset. If the port does not receive an IGMP report when the timer expires, the port is removed from the associated dynamic forwarding entry.

• Static member port—When a port is statically configured as a member port, it is added to the

associated static IGMP snooping forwarding entry as an outgoing interface. The static member port does not age out, and it can be deleted only manually.

rnet 1/0/2 and GigabitEthernet 1/0/3 of Switch A and GigabitEthernet 1/0/2

Unless otherwise specified, router ports and member ports in this document include both static and dynamic router ports and member ports.

How IGMP snooping works

The ports in this section are dynamic ports. For information about how to configure and remove static ports, see "Configuring static ports."

messages types include general query, IGMP report, and leave message. An IGMP

IGMP snooping-enabled Layer 2 device performs differently depending on the message types.

General query

The IGMP querier periodically sends IGMP general queries to all hosts and routers on the local subnet to check for the existence of multicast group members.

After receiving an IGMP general query, the Layer 2 device forwards the query to all ports in the VLAN except the receiving port. The Layer 2 device also performs one of the following actions:

• If the receiving port is a dynamic router port in the dynamic router port list, the Layer 2 device

restarts the aging timer for the port.

• If the receiving port does not exist in the dynamic router port list, the Layer 2 device adds the

port to the dynamic router port list. It also starts an aging timer for the port.

IGMP report

A host sends an IGMP report to the IGMP querier for the following purposes:

• Responds to queries if the host is a multicast group member.

• Applies for a multicast group membership.

After receiving an IGMP report from a host, the Layer 2 device forwards the report through all the router ports in the VLAN. It also resolves the address of the reported multicast group, and looks up the forwarding table for a matching entry as follows:

• If no match is found, the Layer 2 device creates a forwarding entry with the receiving port as an

outgoing interface. It also marks the receiving port as a dynamic member port and starts an aging timer for the port.

• If a match is found but the matching forwarding entry does not contain the receiving port, the

Layer 2 device adds the receiving port to the outgoing interface list. It also marks the receiving port as a dynamic member port and starts an aging timer for the port.

• If a match is found and the matching forwarding entry contains the receiving port, the Layer 2

device restarts the aging timer for the port.

In an application with a group policy configured on an IGMP snooping-enabled Layer 2 device, when a user requests a multicast program, the user's host initiates an IGMP report. After receiving this report, the Layer 2 device resolves the multicast group address in the report and performs ACL filtering on the report. If the report passes ACL filtering, the Layer 2 device creates an IGMP snooping forwarding entry for the multicast group with the receiving port as an outgoing interface. If the report does not pass ACL filtering, the Layer 2 device drops this report. The multicast data for the multicast group is not sent to this port, and the user cannot retrieve the program.

A Layer 2 device does not forward an IGMP report through a non-router port because of the host IGMP report suppression mechanism. For more information about the mechanism, see "Configuring

IGMP."

Leave message

An IGMPv1 receiver host does not send any leave messages when it leaves a multicast group. The Layer 2 device cannot immediately update the status of the port that connects to the receiver host. The Layer 2 device does not remove the port from the outgoing interface list in the associated forwarding entry until the aging time for the group expires.

An IGMPv2 or IGMPv3 host sends an IGMP leave message when it leaves a multicast group.

When the Layer 2 device receives an IGMP leave message on a dynamic member port, the Layer 2 device first examines whether a forwarding entry matches the group address in the message.

• If no match is found, the Layer 2 device discards the IGMP leave message.

• If a match is found but the receiving port is not an outgoing interface in the forwarding entry, the

Layer 2 device discards the IGMP leave message.

• If a match is found and the receiving port is not the only outgoing interface in the forwarding

entry, the Layer 2 device performs the following actions:

{ Discards the IGMP leave message.

{ Sends an IGMP group-specific query to identify whether the group has active receivers

attached to the receiving port.

{ Sets the aging timer for the receiving port to twice the IGMP last member query interval.

• If a match is found and the receiving port is the only outgoing interface in the forwarding entry,

the Layer 2 device performs the following actions:

{ Forwards the IGMP leave message to all router ports in the VLAN.

{ Sends an IGMP group-specific query to identify whether the group has active receivers

attached to the receiving port.

{ Sets the aging timer for the receiving port to twice the IGMP last member query interval.

After receiving the IGMP leave message on a port, the IGMP querier resolves the multicast group address in the message. Then, it sends an IGMP group-specific query to the multicast group through the receiving port.

After receiving the IGMP group-specific query, the Layer 2 device forwards the query through all its router ports in the VLAN and all member ports of the multicast group. Then, it waits for the responding IGMP report from the directly connected hosts. For the dynamic member port that received the leave message, the Layer 2 device also performs one of the following actions:

• If the port receives an IGMP report before the aging timer expires, the Layer 2 device resets the

aging timer.

• If the port does not receive an IGMP report when the aging timer expires, the Layer 2 device

removes the port from the forwarding entry for the multicast group.

Protocols and standards

RFC 4541, Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches

General configuration restrictions and guidelines

When you configure IGMP snooping, follow these restrictions and guidelines:

• For a VLAN configured with IGMP snooping, if you change the VPN instance bound to the

VLAN interface, Layer 2 multicast traffic for the VLAN is interrupted. In this case, you must

execute the reset igmp-snooping group command so that new IGMP snooping forwarding

entries can be created.

• For IGMP reports received from secondary VLANs, the relevant IGMP snooping forwarding

entries are maintained by the primary VLAN. Therefore, you need to configure IGMP snooping only for the primary VLAN. The IGMP snooping configuration made for secondary VLANs does

not take effect. For more information about primary VLANs and secondary VLANs, see Layer 2—LAN Switching Configuration Guide.

• The IGMP snooping configurations made on Layer 2 aggregate interfaces do not interfere with

the configurations made on member ports. In addition, the configurations made on Layer 2 aggregate interfaces do not take part in aggregation calculations. The configuration made on a member port of the aggregate group takes effect after the port leaves the aggregate group.

IGMP snooping configuration task list

Tasks at a glance

Configuring basic IGMP snooping features:

• (Required.) Enabling IGMP snooping

• (Optiona

• (Optional.) Setting the maximum number of IGMP snooping forwarding entries

• (Optional.) Setting the IGMP last member query interval

Configuring IGMP snooping port features:

• (Optional.) Setting aging timers for dynamic ports

• (Optional.) Configuring static ports

• (Optional.) Configuring a port as a simulated member host

• (Optiona

• (Optional.) Disabling a port from becoming a dynamic router port

Configuring the IGMP snooping querier:

• (Optional.) Enabling the IGMP snooping querier

• (Optional.) Configuring parameters for IGMP general queries and responses

Configuring parameters for IGMP messages:

• (Optional.) Configuring source IP addresses for IGMP messages

• (Optiona

Configuring IGMP snooping policies:

• (Optional.) Configuring a multicast group policy

• (Optiona

• (Optional.) Enabling dropping unknown multicast data

• (Optional.) Enabling IGMP report suppression

• (Optional.) Setting the maximum number of multicast groups on a port

• (Optional.) Enabling multicast group replacement

l.) Specifying an IGMP snooping version

l.) Enabling fast-leave processing

l.) Setting the 802.1p priority for IGMP messages

l.) Enabling multicast source port filtering

Configuring basic IGMP snooping features

Before you configure basic IGMP snooping features, complete the following tasks:

• Configure VLANs.

• Determine the IGMP snooping version.

• Determine the maximum number of IGMP snooping forwarding entries.

• Determine the IGMP last member query interval.

Enabling IGMP snooping

When you enable IGMP snooping, follow these guidelines:

• You must enable IGMP snooping globally before you enable it for a VLAN.

• IGMP snooping configuration made in VLAN view takes effect only on the member ports in that

VLAN.

• You can enable IGMP snooping for the specified VLANs in IGMP-snooping view or for a VLAN

in VLAN view. For a VLAN, the configuration in VLAN view has the same priority as the configuration in IGMP-snooping view, and the most recent configuration takes effect.

Enabling IGMP snooping for the specified VLANs

Step Command Remarks

1. Enter system view.

2. Enable IGMP snooping

globally and enter IGMP-snooping view.

3. Enable IGMP snooping for

the specified VLANs.

system-view

igmp-snooping

enable vlan

vlan-list

Enabling IGMP snooping for a VLAN

Step Command Remarks

1. Enter system view.

2. Enable IGMP snooping

globally and enter IGMP-snooping view.

3. Return to system view.

4. Enter VLAN view.

5. Enable IGMP snooping for

the VLAN.

system-view

igmp-snooping

quit vlan

vlan-id

igmp-snooping enable

Specifying an IGMP snooping version

N/A

By default, IGMP snooping is globally disabled.

By default, IGMP snooping is disabled for a VLAN.

N/A

By default, IGMP snooping is disabled.

N/A

By default, IGMP snooping is disabled in a VLAN.

Different IGMP snooping versions process different versions of IGMP messages.

• IGMPv2 snooping processes IGMPv1 and IGMPv2 messages, but it floods IGMPv3 messages

in the VLAN instead of processing them.

• IGMPv3 snooping processes IGMPv1, IGMPv2, and IGMPv3 messages.

If you change IGMPv3 snooping to IGMPv2 snooping, the switch does the following:

• Clears all IGMP snooping forwarding entries that are dynamically added.

• Keeps static IGMPv3 snooping forwarding entries (*, G).

• Clears static IGMPv3 snooping forwarding entries (S, G), which will be restored when IGMP

snooping is switched back to IGMPv3 snooping.

For more information about static IGMP snooping forwarding entries, see "Configuring static ports."

You can specify the version for the specified VLANs in IGMP-snooping view or for a VLAN in VLAN view. For a VLAN, the configuration in VLAN view has the same priority as the configuration in IGMP-snooping view, and the most recent configuration takes effect.

Specifying an IGMP snooping version for the specified VLANs

Step Command Remarks

1. Enter system view.

2. Enable IGMP snooping

globally and enter IGMP-snooping view.

system-view

igmp-snooping

N/A

3. Specify an IGMP snooping

version for the specified

version

vlan-list

version-number

vlan

The default setting is 2.

VLANs.

Specifying an IGMP snooping version for a VLAN

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Specify an IGMP snooping

version for the VLAN.

system-view vlan

vlan-id

igmp-snooping version

version-number

N/A

The default setting is 2.

Setting the maximum number of IGMP snooping forwarding entries

You can set the maximum number of IGMP snooping forwarding entries, including dynamic entries and static entries. When the number of forwarding entries on the switch reaches the upper limit, the switch does not automatically remove any existing entries. As a best practice, manually remove some entries to allow new entries to be created.

To set the maximum number of IGMP snooping forwarding entries:

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Set the maximum number of

IGMP snooping forwarding entries.

system-view igmp-snooping

entry-limit

N/A

limit

N/A

The default setting is

4294967295.

Setting the IGMP last member query interval

A receiver host starts a report delay timer for a multicast group when it receives an IGMP group-specific query for the group. This timer is set to a random value in the range of 0 to the maximum response time advertised in the query. When the timer value decreases to 0, the host sends an IGMP report to the group.

The IGMP last member query interval defines the maximum response time advertised in IGMP group-specific queries. Set an appropriate value for the IGMP last member query interval to speed up hosts' responses to IGMP group-specific queries and avoid IGMP report traffic bursts.

Configuration restrictions and guidelines

When you set the IGMP last member query interval, follow these restrictions and guidelines:

• The Layer 2 device does not send an IGMP group-specific query if it receives an IGMP leave

message from a port enabled with fast-leave processing.

• You can set the IGMP last member query interval globally for all VLANs in IGMP-snooping view

or for a VLAN in VLAN view. For a VLAN, the VLAN-specific configuration takes priority over the global configuration.

Setting the IGMP last member query interval globally

Step Command Remarks

1. Enter system view.

system-view

N/A

Step Command Remarks

2. Enter IGMP-snooping view.

3. Set the IGMP last member

query interval globally.

igmp-snooping last-member-query-interval

interval

Setting the IGMP last member query interval in a VLAN

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

system-view vlan

vlan-id N/A

N/A

The default setting is 1 second.

N/A

3. Set the IGMP last member

query interval for the VLAN.

igmp-snooping last-member-query-interval

interval

The default setting is 1 second.

Configuring IGMP snooping port features

Before you configure IGMP snooping port features, complete the following tasks:

• Enable IGMP snooping for the VLAN.

• Determine the aging timer for dynamic router ports.

• Determine the aging timer for dynamic member ports.

• Determine the addresses of the multicast group and multicast source.

Setting aging timers for dynamic ports

When you set aging timers for dynamic ports, follow these guidelines:

• If the memberships of multicast groups frequently change, you can set a relatively small value

for the aging timer of the dynamic member ports. If the memberships of multicast groups rarely change, you can set a relatively large value.

• If a dynamic router port receives a PIMv2 hello message, the aging timer for the port is specified by the hello message. In this case, the router-aging-time or igmp-snooping router-aging-time command does not take effect on the port.

• IGMP group-specific queries originated by the Layer 2 device trigger the adjustment of aging

timers for dynamic member ports. If a dynamic member port receives such a query, its aging timer is set to twice the IGMP last member query interval. For more information about setting the IGMP last member query interval on the Layer 2 device, see "Setting the IGMP last member

query inte

• You can set the timers globally for all VLANs in IGMP-snooping view or for a VLAN in VLAN

view. For a VLAN, the VLAN-specific configuration takes priority over the global configuration.

rval."

Setting the aging timers for dynamic ports globally

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Set the aging timer for

dynamic router ports globally.

4. Set the global aging timer for

dynamic member ports

system-view igmp-snooping

router-aging-time

host-aging-time

N/A

interval

N/A

The default setting is 260 seconds.

globally.

Setting the aging timers for dynamic ports in a VLAN

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Set the aging timer for

dynamic router ports in the VLAN.

4. Set the aging timer for

dynamic member ports in the VLAN.

system-view vlan

vlan-id

igmp-snooping router-aging-time

igmp-snooping host-aging-time

N/A

interval

Configuring static ports

You can configure the following types of static ports:

• Static member port—When you configure a port as a static member port for a multicast group,

all hosts attached to the port will receive multicast data for the group.

The static member port does not respond to IGMP queries. When you complete or cancel this configuration on a port, the port does not send an unsolicited IGMP report or leave message.

• Static router port—When you configure a port as a static router port for a multicast group, all

multicast data for the group received on the port will be forwarded.

interval

N/A

The default setting is 260 seconds.

To configure static ports:

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

3. Configure the port as a static

port.

system-view

interface

interface-number

• Configure the port as a static

member port:

igmp-snooping static-group group-address [ source-ip source-address ] vlan vlan-id

• Configure the port as a static router port:

igmp-snooping static-router-port vlan

vlan-id

N/A

interface-type

N/A

By default, a port is not a static member port or static router port.

Configuring a port as a simulated member host

When a port is configured as a simulated member host, it is equivalent to an independent host in the following ways:

• It sends an unsolicited IGMP report when you complete the configuration.

• It responds to IGMP general queries with IGMP reports.

• It sends an IGMP leave message when you cancel the configuration.

The version of IGMP running on the simulated member host is the same as the version of IGMP snooping running on the port. The port ages out in the same way as a dynamic member port.

To configure a port as a simulated member host:

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

system-view

interface

interface-number

interface-type

N/A

3. Configure the port as a

simulated member host.

igmp-snooping host-join

group-address [ source-address ]

Enabling fast-leave processing

This feature enables the switch to immediately remove a port from the forwarding entry for a multicast group when the port receives a leave massage.

Configuration restrictions and guidelines

When you enable fast-leaving processing, follow these restrictions and guidelines:

• Do not enable fast-leave processing on a port that has multiple receiver hosts in a VLAN. If

fast-leave processing is enabled, after a receiver host leaves a multicast group, the other receivers cannot receive multicast data for the group.

• You can enable fast-leave processing globally for all ports in IGMP-snooping view or for a port

in interface view. For a port, the port-specific configuration takes priority over the global configuration.

Enabling fast-leave processing globally

Step Command Remarks

1. Enter system view.

system-view

source-ip

vlan

vlan-id

N/A

By default, the port is not a simulated member host.

2. Enter IGMP-snooping view.

3. Enable fast-leave

processing globally.

igmp-snooping

fast-leave [ vlan

vlan-list

]

N/A

By default, fast-leave processing is disabled.

Enabling fast-leave processing on a port

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

3. Enable fast-leave

processing on the port.

system-view

interface

interface-number

igmp-snooping fast-leave [ vlan

vlan-list

N/A

interface-type

]

N/A

By default, fast-leave processing is disabled.

Disabling a port from becoming a dynamic router port

A receiver host might send an IGMP general query or PIM hello message for testing purposes. In this case, the following problems might exist:

• The port that receives the IGMP general query or PIM hello message becomes a dynamic

router port. Before its aging timer expires, this dynamic router port receives all multicast packets within the VLAN where the port belongs and forwards them to the host. The receiver host will receive multicast data that it does not want to receive.

• The IGMP general query or PIM hello message that the host sends affects the multicast routing

protocol state on Layer 3 devices, such as the IGMP querier or DR election. This might further cause network interruption.

To solve these problems and to improve network security and the control over multicast users, you can disable a port from becoming a dynamic router port.

To disable a port from becoming a dynamic router port:

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

3. Disable the port from

becoming a dynamic router port.

system-view

interface

interface-number

igmp-snooping router-port-deny [ vlan

interface-type

vlan-list

N/A

By default, a port can become a dynamic router port.

This configuration does not affect

]

the static router port configuration.

Configuring the IGMP snooping querier

This section describes how to configure an IGMP snooping querier.

Configuration prerequisites

Before you configure the IGMP snooping querier, complete the following tasks:

• Enable IGMP snooping for the VLAN.

• Determine the IGMP general query interval.

• Determine the maximum response time for IGMP general queries.

Enabling the IGMP snooping querier

This feature enables the switch to periodically send IGMP general queries to establish and maintain multicast forwarding entries at the data link Layer. You can configure an IGMP snooping querier on a network without Layer 3 multicast devices.

Do not enable the IGMP snooping querier on a multicast network that runs IGMP. An IGMP snooping querier does not take part in IGMP querier elections. However, it might affect IGMP querier elections if it sends IGMP general queries with a low source IP address.

To enable the IGMP snooping querier for a VLAN:

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Enable the IGMP snooping querier.

system-view

vlan-id

vlan

igmp-snooping querier

N/A

By default, the IGMP snooping querier is disabled.

Configuring parameters for IGMP general queries and responses

CAUTION:

To avoid mistakenly deleting multicast group members, make sure the IGMP general query interval is greater than the maximum response time for IGMP general queries.

You can modify the IGMP general query interval for a VLAN based on the actual condition of the network.

A receiver host starts a report delay timer for each multicast group that it has joined when it receives an IGMP general query. This timer is set to a random value in the range of 0 to the maximum response time advertised in the query. When the timer value decreases to 0, the host sends an IGMP report to the corresponding multicast group.

Configuration restrictions and guidelines

When you configure parameters for IGMP general queries and responses, follow these restrictions and guidelines:

• Set an appropriate value for the maximum response time for IGMP general queries to speed up

hosts' responses to IGMP general queries and avoid IGMP report traffic bursts.

• You can configure set the maximum response time for IGMP general queries globally for all

VLANs in IGMP-snooping view or for a VLAN in VLAN view. For a VLAN, the VLAN-specific configuration takes priority over the global configuration.

Configuring the parameters for IGMP general queries and responses globally

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Set the maximum response

time for IGMP general queries.

system-view igmp-snooping

max-response-time

interval

N/A

The default setting is 10 seconds.

Configuring parameters for IGMP general queries and responses in a VLAN

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Set the IGMP general query

interval in the VLAN.

4. Set the maximum response

time for IGMP general queries in the VLAN.

system-view vlan

vlan-id N/A

igmp-snooping query-interval

interval

igmp-snooping max-response-time

interval

N/A

The default setting is 125 seconds.

The default setting is 10 seconds.

Configuring parameters for IGMP messages

This section describes how to configure parameters for IGMP messages.

Configuration prerequisites

Before you configure parameters for IGMP messages, complete the following tasks:

• Enable IGMP snooping for the VLAN.

• Determine the source IP address of IGMP general queries.

• Determine the source IP address of IGMP group-specific queries.

• Determine the source IP address of IGMP reports.

• Determine the source IP address of IGMP leave messages.

• Determine the 802.1p priority of IGMP messages

Configuring source IP addresses for IGMP messages

The IGMP snooping querier might send IGMP general queries with the source IP address 0.0.0.0. The port that receives such queries will not be maintained as a dynamic router port. This might prevent the associated dynamic IGMP snooping forwarding entry from being correctly created at the data link layer and eventually cause multicast traffic forwarding failures.

To avoid this problem, you can configure a non-all-zero IP address as the source IP address of the IGMP queries on the IGMP snooping querier. This configuration might affect the IGMP querier election within the subnet.

You can also change the source IP address of IGMP reports or leave messages sent by a simulated member host.

To configure source IP addresses for IGMP messages in a VLAN:

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Configure the source IP

address for IGMP general queries.

4. Configure the source IP

address for IGMP group-specific queries.

system-view

vlan-id

vlan

igmp-snooping general-query source-ip

ip-address

igmp-snooping special-query source-ip

ip-address

N/A

By default, the source IP address of IGMP general queries is the IP address of the current VLAN interface. If the current VLAN interface does not have an IP address, the source IP address is

0.0.0.0.

By default, the source IP address of IGMP group-specific queries is one of the following:

• The source address of IGMP

• The IP address of the current

• 0.0.0.0 if the IGMP snooping

group-specific queries if the IGMP snooping querier has received IGMP general queries.

VLAN interface if the IGMP snooping querier does not receive an IGMP general query.

querier does not receive an IGMP general query and the current VLAN interface does not have an IP address.

5. Configure the source IP

address for IGMP reports.

igmp-snooping report source-ip

ip-address

By default, the source IP address of IGMP reports is the IP address of the current VLAN interface. If the current

VLAN interface does not have an IP address, the source IP address is

0.0.0.0.

By default, the source IP address of

6. Configure the source IP

address for IGMP leave messages.

igmp-snooping leave source-ip

ip-address

IGMP leave messages is the IP address of the current VLAN interface. If the current VLAN interface does not have an IP address, the source IP address is

0.0.0.0.

Setting the 802.1p priority for IGMP messages

When congestion occurs on outgoing ports of the switch, it forwards IGMP messages in their 802.1p priority order, from highest to lowest. You can assign higher 802.1p priority to IGMP messages that are created or forwarded by the switch.

You can set the 802.1p priority globally for all VLANs in IGMP-snooping view or for a VLAN in VLAN view. For a VLAN, the VLAN-specific configuration takes priority over the global configuration.

Setting the 802.1p priority for IGMP messages globally

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

system-view igmp-snooping

N/A

3. Set the 802.1p priority for IGMP messages.

dot1p-priority

priority-number

The default setting is 0.

The global configuration takes effect on all VLANs.

Setting the 802.1p priority for IGMP messages in a VLAN

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Set the 802.1p priority for

IGMP messages in the VLAN.

system-view vlan

vlan-id N/A

igmp-snooping dot1p-priority

priority-number

N/A

The default setting is 0.

Configuring IGMP snooping policies

Before you configure IGMP snooping policies, complete the following tasks:

• Enable IGMP snooping for the VLAN.

• Determine the ACL to be used by the multicast group policy.

• Determine the maximum number of multicast groups that a port can join.

Configuring a multicast group policy

This feature enables the switch to filter IGMP reports based on the used ACL that specifies the multicast groups and the optional sources. Use this feature to control the multicast groups that receiver hosts can join.

Configuration restrictions and guidelines

When you configure a multicast group policy, follow these guidelines:

• This configuration takes effect only on the multicast groups that ports join dynamically.

• You can configure a multicast group policy globally for all ports in IGMP-snooping view or for a

port in interface view. For a port, the port-specific configuration takes priority over the global configuration.

Configuring a multicast group policy globally

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

system-view igmp-snooping

N/A

3. Configure a multicast group

policy globally.

group-policy

vlan-list

]

acl-number [

Configuring a multicast group policy on a port

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

3. Configure a multicast group

policy on the port.

system-view

interface

interface-number

igmp-snooping group-policy

acl-number [

N/A

vlan-list

]

interface-type

vlan

Enabling multicast source port filtering

This feature enables the switch to discard all multicast data packets and to accept multicast protocol packets. You can enable this feature on ports that connect only to multicast receivers.

You can enable this feature for the specified ports in IGMP-snooping view or for a port in interface view. For a port, the configuration in interface view has the same priority as the configuration in IGMP-snooping view, and the most recent configuration takes effect.

vlan

By default, no multicast group policies exist. Hosts can join any multicast groups.

N/A

By default, no multicast group policies exist on a port. Hosts attached to the port can join any multicast groups.

Enabling multicast source port filtering for the specified ports

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Enable multicast source port

filtering.

system-view igmp-snooping

source-deny port

interface-list

Enabling multicast source port filtering for a port

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view.

system-view interface

interface-number

interface-type

N/A

By default, multicast source port filtering is disabled.

N/A

3. Enable multicast source port filtering.

igmp-snooping source-deny

Enabling dropping unknown multicast data

This feature enables the switch to drop all unknown multicast data. Unknown multicast data refers to multicast data for which no forwarding entries exist in the IGMP snooping forwarding table.

Configuration restrictions and guidelines

When you enable dropping unknown multicast data, follow these restrictions and guidelines:

• You can enable this feature globally for all VLANs in IGMP-snooping view or for a VLAN in

VLAN view.

• The drop-unknown command in IGMP-snooping view and the igmp-snooping drop-unknown command in VLAN view are mutually exclusive. You cannot configure them on

the same switch.

• If you enable dropping unknown IPv6 and IPv4 multicast data, enable both of them globally or

for the same VLANs to ensure correct multicast forwarding. For more information about enabling dropping unknown IPv6 multicast data, see "Configuring MLD snooping."

• Whe

Enabling dropping unknown multicast data globally

n dropping unknown multicast data is enabled, the switch still forwards unknown multicast

data to other router ports in the VLAN.

By default, multicast source port filtering is disabled.

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Enable dropping unknown

multicast data globally.

system-view igmp-snooping

drop-unknown

N/A

Enabling dropping unknown multicast data in a VLAN

Step Command Remarks

1. Enter system view.

2. Enter VLAN view.

3. Enable dropping unknown

multicast data for the VLAN.

system-view vlan

vlan-id

igmp-snooping drop-unknown

N/A

Enabling IGMP report suppression

N/A

By default, dropping unknown multicast data is disabled. Unknown multicast data is flooded in the VLAN to which the data belongs.

N/A

By default, dropping unknown multicast data is disabled. Unknown multicast data is flooded in the VLAN to which the data belongs.

This feature enables the switch to forward only the first IGMP report for a multicast group to its directly connected Layer 3 device. Other reports for the same group in the same query interval are discarded. This reduces the multicast traffic.

To enable IGMP report suppression:

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Enable IGMP report

suppression.

system-view igmp-snooping

report-aggregation

N/A

By default, IGMP report suppression is enabled.

Setting the maximum number of multicast groups on a port

You can set the maximum number of multicast groups on a port to regulate the port traffic.

Configuration restrictions and guidelines

When you set the maximum number of multicast groups on a port, follow these guidelines:

• This configuration takes effect only on the multicast groups that a port joins dynamically.

• If the number of multicast groups on a port exceeds the limit, the system removes all the

forwarding entries related to that port. The receiver hosts attached to that port can join multicast groups again before the number of multicast groups on the port reaches the limit.

Configuration procedure

To set the maximum number of multicast groups on a port:

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

3. Set the maximum number of

multicast groups on a port.

system-view

interface

interface-number

igmp-snooping group-limit

vlan

[

N/A

interface-type

vlan-list ]

limit

N/A

The default setting is

4294967295.

Enabling multicast group replacement

This feature enables the switch to replace an existing group with a newly joined group when the number of groups exceeds the upper limit. This feature is typically used in the channel switching application. Without this feature, the switch discards IGMP reports for new groups, and the user cannot change to the new channel.

Configuration restrictions and guidelines

When you enable multicast group replacement, follow these guidelines:

• This configuration takes effect only on the multicast groups that a port joins dynamically.

• You can enable this feature globally for all ports in IGMP-snooping view or for a port in interface

view. For a port, the port-specific configuration takes priority over the global configuration.

Enabling multicast group replacement globally

Step Command Remarks

1. Enter system view.

2. Enter IGMP-snooping view.

3. Enable multicast group

replacement globally.

system-view igmp-snooping

overflow-replace [ vlan

N/A

vlan-list ]

N/A

By default, multicast group replacement is disabled.

Enabling multicast group replacement on a port

Step Command Remarks

1. Enter system view.

2. Enter Layer 2 Ethernet

interface view or Layer 2 aggregate interface view.

3. Enable multicast group

replacement on a port.

system-view

interface

interface-number

igmp-snooping overflow-replace [ vlan

N/A

interface-type

vlan-list ]

N/A

By default, multicast group replacement is disabled.

Displaying and maintaining IGMP snooping

Execute display commands in any view and reset commands in user view.

Task Command

Display IGMP snooping status.

display igmp-snooping

global

[

vlan

vlan-id ]

Display dynamic IGMP snooping forwarding entries (in standalone mode).

Display dynamic IGMP snooping forwarding entries (in IRF mode).

Display dynamic router port information (in standalone mode).

Display dynamic router port information (in IRF mode).

Display static IGMP snooping forwarding entries (in standalone mode).

Display static IGMP snooping forwarding entries (in IRF mode).

Display static router port information (in standalone mode).

Display static router port information (in IRF mode).

Display statistics for the IGMP messages learned by IGMP snooping.

display igmp-snooping group

slot

vlan

slot-number ]

vlan

slot-number ]

source-address ] * [ slot-number ]

display igmp-snooping group

source-address ] * [ chassis-number

display igmp-snooping router-port

slot-number ]

display igmp-snooping router-port

chassis-number

display igmp-snooping static-group

source-address ] * [ slot-number ]

display igmp-snooping static-group

source-address ] * [ chassis-number

display igmp-snooping static-router-port

slot

[

slot-number ]

display igmp-snooping static-router-port

chassis

[

display igmp-snooping statistics

chassis-number

[ group-address |

vlan-id ] [

[ group-address |

vlan-id ] [

slot

slot-number ]

verbose

vlan

[

vlan

[

[ group-address |

verbose

[ group-address |

verbose

slot

] [

chassis

] [

vlan-id ] [

slot

] [

chassis

] [

vlan

[

vlan-id ]

vlan

[

vlan-id ]

slot

chassis

Display information about Layer 2 IP multicast groups (in standalone mode).

Display information about Layer 2 IP multicast groups (in IRF mode).

Display Layer 2 IP multicast group entries (in standalone mode).

Display Layer 2 IP multicast group entries (in IRF mode).

display l2-multicast ip

source-address ] * [

display l2-multicast ip

source-address ] * [

slot

slot-number ]

display l2-multicast ip forwarding source

source-address ] * [

display l2-multicast ip forwarding source

source-address ] * [

chassis-number

slot

group

[

vlan

[

vlan

slot-number ]

group-address |

vlan-id ] [

group

group-address |

vlan-id ] [

vlan

vlan-id ] [

slot

slot-number ]

chassis

group

[

group

[

source

chassis-number

group-address |

slot

slot-number ]

group-address |

chassis

Display information about Layer 2 MAC multicast groups (in standalone mode).

display l2-multicast mac

slot-number ]

[ mac-address ] [

vlan

vlan-id ] [

slot

Display information about Layer 2 MAC multicast groups (in IRF mode).

Display Layer 2 MAC multicast group entries (in standalone mode).

Display Layer 2 MAC multicast group entries (in IRF mode).

Clear dynamic IGMP snooping forwarding entries.

Clear dynamic router port information.

Clear statistics for the IGMP messages learned through IGMP snooping.

display l2-multicast mac

chassis

[

display l2-multicast mac forwarding

vlan-id ] [

display l2-multicast mac forwarding

vlan-id ] [

reset igmp-snooping group

[ source-address ] |

reset igmp-snooping router-port

reset igmp-snooping statistics

chassis-number

slot

slot-number ]

chassis

chassis-number

[ mac-address ] [

slot

{ group-address

all

vlan

} [

slot-number ]

slot

vlan-id ]

{

vlan

vlan-id ]

[ mac-address ] [

slot-number ]

all

vlan

vlan-id }

vlan

IGMP snooping configuration examples

Group policy and simulated joining configuration example

Network requirements

As shown in Figure 12, Router A runs IGMPv2 and acts as the IGMP querier. Switch A runs IGMPv2 snooping.

Configure a group policy and simulated joining to meet the following requirements:

• Host A and Host B receive only the multicast data addressed to multicast group 224.1.1.1.

Multicast data can be forwarded through GigabitEthernet 1/0/3 and GigabitEthernet 1/0/4 of Switch A uninterruptedly, even though Host A and Host B fail to receive the multicast data.

• Switch A will drop unknown multicast data instead of flooding it in VLAN 100.

Figure 12 Network diagram

Configuration procedure

1. Assign an IP address and subnet mask to each interface according to Figure 12. (Details not

shown.)

2. Configure Router A:

# Enable IP multicast routing.

<RouterA> system-view [RouterA] multicast routing [RouterA-mrib] quit

# Enable IGMP on GigabitEthernet 1/0/1.

[RouterA] interface gigabitethernet 1/0/1 [RouterA-GigabitEthernet1/0/1] igmp enable [RouterA-GigabitEthernet1/0/1] quit

# Enable PIM-DM on GigabitEthernet 1/0/2.

[RouterA] interface gigabitethernet 1/0/2 [RouterA-GigabitEthernet1/0/2] pim dm [RouterA-GigabitEthernet1/0/2] quit

3. Configure Switch A:

# Enable IGMP snooping globally.

<SwitchA> system-view [SwitchA] igmp-snooping [SwitchA-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/4 to the VLAN.

[SwitchA] vlan 100 [SwitchA-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/4

# Enable IGMP snooping, and enable dropping unknown multicast data for VLAN 100.

[SwitchA-vlan100] igmp-snooping enable [SwitchA-vlan100] igmp-snooping drop-unknown [SwitchA-vlan100] quit

# Configure a multicast group policy so that the hosts in VLAN 100 can join only multicast group

224.1.1.1.

[SwitchA] acl number 2001 [SwitchA-acl-basic-2001] rule permit source 224.1.1.1 0 [SwitchA-acl-basic-2001] quit [SwitchA] igmp-snooping [SwitchA-igmp-snooping] group-policy 2001 vlan 100 [SwitchA-igmp-snooping] quit

# Configure GigabitEthernet 1/0/3 and GigabitEthernet 1/0/4 as simulated member hosts of multicast group 224.1.1.1.

[SwitchA] interface gigabitethernet 1/0/3 [SwitchA-GigabitEthernet1/0/3] igmp-snooping host-join 224.1.1.1 vlan 100 [SwitchA-GigabitEthernet1/0/3] quit [SwitchA] interface gigabitethernet 1/0/4 [SwitchA-GigabitEthernet1/0/4] igmp-snooping host-join 224.1.1.1 vlan 100 [SwitchA-GigabitEthernet1/0/4] quit

Verifying the configuration

# Send IGMP reports from Host A and Host B to join multicast groups 224.1.1.1 and 224.2.2.2. (Details not shown.)

# Display dynamic IGMP snooping forwarding entries for VLAN 100 on Switch A.

[SwitchA] display igmp-snooping group vlan 100 Total 1 entries.

VLAN 100: Total 1 entries. (0.0.0.0, 224.1.1.1) Host slots (0 in total): Host ports (2 in total): GE1/0/3 (00:03:23) GE1/0/4 (00:04:10)

The output shows the following information:

• Host A and Host B have joined multicast group 224.1.1.1 through the member ports

GigabitEthernet 1/0/3 and GigabitEthernet1/0/4 on Switch A, respectively.

• Host A and Host B have failed to join multicast group 224.2.2.2.

Static port configuration example

Network requirements

As shown in Figure 13:

• Router A runs IGMPv2 and acts as the IGMP querier. Switch A, Switch B, and Switch C run

IGMPv2 snooping.

• Host A and host C are permanent receivers of multicast group 224.1.1.1.

Configure static ports to meet the following requirements:

• To enhance the reliability of multicast traffic transmission, configure GigabitEthernet 1/0/3 and

GigabitEthernet 1/0/5 on Switch C as static member ports for multicast group 224.1.1.1.

• Suppose the STP runs on the network. To avoid data loops, the forwarding path from Switch A

to Switch C is blocked. Multicast data flows to the receivers attached to Switch C only along the path of Switch A—Switch B—Switch C. When this path is blocked, at least one IGMP query-response cycle must be completed before multicast data flows to the receivers along the path of Switch A—Switch C. In this case, the multicast delivery is interrupted during the process.

For more information about the STP, see Layer 2—LAN Switching Configuration Guide.

Configure GigabitEthernet 1/0/3 on Switch A as a static router port. Then, multicast data can flow to the receivers nearly uninterruptedly along the path of Switch A—Switch C when the path of Switch A—Switch B—Switch C is blocked.

Figure 13 Network diagram

Source

1.1.1.1/24

GE1/0/2

1.1.1.2/24

Router A

IGMP querier

GE1/0/1

10.1.1.1/24

Switch A

GE1/0/1

Switch B

Switch C

Configuration procedure

1. Assign an IP address and subnet mask to each interface according to Figure 13. (Details not

shown.)

2. Configure Router A:

# Enable IP multicast routing.

<RouterA> system-view [RouterA] multicast routing [RouterA-mrib] quit

# Enable IGMP on GigabitEthernet 1/0/1.

[RouterA] interface gigabitethernet 1/0/1 [RouterA-GigabitEthernet1/0/1] igmp enable [RouterA-GigabitEthernet1/0/1] quit

# Enable PIM-DM on GigabitEthernet 1/0/2.

[RouterA] interface gigabitethernet 1/0/2 [RouterA-GigabitEthernet1/0/2] pim dm [RouterA-GigabitEthernet1/0/2] quit

3. Configure Switch A:

# Enable IGMP snooping globally.

<SwitchA> system-view [SwitchA] igmp-snooping [SwitchA-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/3 to the VLAN.

[SwitchA] vlan 100 [SwitchA-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/3

# Enable IGMP snooping for VLAN 100.

[SwitchA-vlan100] igmp-snooping enable

VLAN 100

Host C

Receiver

Host A

Receiver

Host B

[SwitchA-vlan100] quit

# Configure GigabitEthernet 1/0/3 as a static router port for VLAN 100.

[SwitchA] interface gigabitethernet 1/0/3 [SwitchA-GigabitEthernet1/0/3] igmp-snooping static-router-port vlan 100 [SwitchA-GigabitEthernet1/0/3] quit

4. Configure Switch B:

# Enable IGMP snooping globally.

<SwitchB> system-view [SwitchB] igmp-snooping [SwitchB-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 to the VLAN.

[SwitchB] vlan 100 [SwitchB-vlan100] port gigabitethernet 1/0/1 gigabitethernet 1/0/2

# Enable IGMP snooping for VLAN 100.

[SwitchB-vlan100] igmp-snooping enable [SwitchB-vlan100] quit

5. Configure Switch C:

# Enable IGMP snooping globally.

<SwitchC> system-view [SwitchC] igmp-snooping [SwitchC-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/5 to the VLAN.

[SwitchC] vlan 100 [SwitchC-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/5

# Enable IGMP snooping for VLAN 100.

[SwitchC-vlan100] igmp-snooping enable [SwitchC-vlan100] quit

# Configure GigabitEthernet 1/0/3 and GigabitEthernet 1/0/5 as static member ports for multicast group 224.1.1.1.

[SwitchC] interface gigabitethernet 1/0/3 [SwitchC-GigabitEthernet1/0/3] igmp-snooping static-group 224.1.1.1 vlan 100 [SwitchC-GigabitEthernet1/0/3] quit [SwitchC] interface gigabitethernet 1/0/5 [SwitchC-GigabitEthernet1/0/5] igmp-snooping static-group 224.1.1.1 vlan 100 [SwitchC-GigabitEthernet1/0/5] quit

Verifying the configuration

# Display static router port information for VLAN 100 on Switch A.

[SwitchA] display igmp-snooping static-router-port vlan 100 VLAN 100: Router slots (0 in total): Router ports (1 in total): GE1/0/3

The output shows that GigabitEthernet 1/0/3 on Switch A has become a static router port.

# Display static IGMP snooping forwarding entries for VLAN 100 on Switch C.

[SwitchC] display igmp-snooping static-group vlan 100 Total 1 entries.

VLAN 100: Total 1 entries. (0.0.0.0, 224.1.1.1) Host slots (0 in total): Host ports (2 in total): GE1/0/3 GE1/0/5

The output shows that GigabitEthernet 1/0/3 and GigabitEthernet 1/0/5 on Switch C have become static member ports of multicast group 224.1.1.1.

IGMP snooping querier configuration example

Network requirements

As shown in Figure 14:

• The network is a Layer 2-only network.

• Source 1 and Source 2 send multicast data to multicast groups 224.1.1.1 and 225.1.1.1,

respectively.

• Host A and Host C are receivers of multicast group 224.1.1.1, and Host B and Host D are

receivers of multicast group 225.1.1.1.

• All host receivers run IGMPv2, and all switches run IGMPv2 snooping. Switch A (which is close

to the multicast sources) acts as the IGMP snooping querier.

Configure the switches to meet the following requirements:

• To prevent the switches from flooding unknown packets in the VLAN, enable all the switches to

drop unknown multicast data packets.

• A switch does not mark a port that receives an IGMP query with source IP address 0.0.0.0 as a

dynamic router port. This adversely affects the establishment of Layer 2 forwarding entries and multicast traffic forwarding. To avoid this, configure the source IP address of IGMP queries as a non-zero IP address.

Figure 14 Network diagram

Configuration procedure

1. Configure Switch A:

# Enable IGMP snooping globally.

<SwitchA> system-view [SwitchA] igmp-snooping [SwitchA-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/3 to the VLAN.

[SwitchA] vlan 100 [SwitchA-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/3

# Enable IGMP snooping, and enable dropping unknown multicast data packets for VLAN 100.

[SwitchA-vlan100] igmp-snooping enable [SwitchA-vlan100] igmp-snooping drop-unknown

# Configure Switch A as the IGMP snooping querier.

[SwitchA-vlan100] igmp-snooping querier [SwitchA-vlan100] quit

# In VLAN 100, configure the source IP address of IGMP general queries and IGMP group-specific queries as 192.168.1.1.

[SwitchA-vlan100] igmp-snooping general-query source-ip 192.168.1.1 [SwitchA-vlan100] igmp-snooping special-query source-ip 192.168.1.1 [SwitchA-vlan100] quit

2. Configure Switch B:

# Enable IGMP snooping globally.

<SwitchB> system-view [SwitchB] igmp-snooping [SwitchB-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/4 to the VLAN.

[SwitchB] vlan 100 [SwitchB-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/4

# Enable IGMP snooping, and enable dropping unknown multicast packets for the VLAN 100.

[SwitchB-vlan100] igmp-snooping enable [SwitchB-vlan100] igmp-snooping drop-unknown [SwitchB-vlan100] quit

3. Configure Switch C:

# Enable IGMP snooping globally.

<SwitchC> system-view [SwitchC] igmp-snooping [SwitchC-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/3 to the VLAN.

[SwitchC] vlan 100 [SwitchC-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/3

# Enable IGMP snooping, and enable dropping unknown multicast data packets for VLAN 100.

[SwitchC-vlan100] igmp-snooping enable [SwitchC-vlan100] igmp-snooping drop-unknown [SwitchC-vlan100] quit

4. Configure Switch D:

# Enable IGMP snooping globally.

<SwitchD> system-view [SwitchD] igmp-snooping [SwitchD-igmp-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 to the VLAN.

[SwitchD] vlan 100 [SwitchD-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/2

# Enable IGMP snooping, and enable dropping unknown multicast data packets for VLAN 100.

[SwitchD-vlan100] igmp-snooping enable [SwitchD-vlan100] igmp-snooping drop-unknown [SwitchD-vlan100] quit

Verifying the configuration

# Display statistics for IGMP messages learned through IGMP snooping on Switch B.

[SwitchB] display igmp-snooping statistics Received IGMP general queries: 3 Received IGMPv1 reports: 0 Received IGMPv2 reports: 12 Received IGMP leaves: 0 Received IGMPv2 specific queries: 0 Sent IGMPv2 specific queries: 0 Received IGMPv3 reports: 0 Received IGMPv3 reports with right and wrong records: 0 Received IGMPv3 specific queries: 0 Received IGMPv3 specific sg queries: 0 Sent IGMPv3 specific queries: 0 Sent IGMPv3 specific sg queries: 0 Received error IGMP messages: 0 The output shows that all switches except Switch A can receive the IGMP general queries

after Switch A acts as the IGMP snooping querier.

Troubleshooting IGMP snooping

Layer 2 multicast forwarding cannot function

Symptom

Layer 2 multicast forwarding cannot function on the Layer 2 device.

Solution

To resolve the problem:

1. Use the display igmp-snooping command to display IGMP snooping status.

2. If IGMP snooping is not enabled, use the igmp-snooping command in system view to enable

IGMP snooping globally. Then, use the igmp-snooping enable command in VLAN view to

enable IGMP snooping for the VLAN.

3. If IGMP snooping is enabled globally but not enabled for the VLAN, use the igmp-snooping enable command in VLAN view to enable IGMP snooping for the VLAN.

4. If the problem persists, contact Hewlett Packard Enterprise Support.

Multicast group policy does not work

Symptom

Hosts can receive multicast data from multicast groups that are not permitted by the multicast group policy.

Solution

To resolve the problem:

1. Use the display acl command to verify that the configured ACL meets the multicast group

policy requirements.

2. Use the display this command in IGMP-snooping view or in a corresponding interface view to

verify that the correct multicast group policy has been applied. If the applied multicast group

policy is not correct, use the group-policy or igmp-snooping group-policy command to apply

the correct multicast group policy.

3. Use the display igmp-snooping command to verify that dropping unknown multicast data is enabled. If it is not enabled, use the drop-unknown or igmp-snooping drop-unknown

command to enable dropping unknown multicast data.

4. If the problem persists, contact Hewlett Packard Enterprise Support.

Configuring PIM snooping

Overview

PIM snooping runs on Layer 2 devices. It works with IGMP snooping to analyze received PIM messages, and adds the ports that are interested in specific multicast data to a PIM snooping routing entry. In this way, the multicast data can be forwarded to only the ports that are interested in the data.

Figure 15 Multicast packet transmission without or with PIM snooping

Source 1

PIM

router 1

PIM

router 3

Multicast packet transmission

when only IGMP snooping runs

Source 2

Layer 2 switch

PIM

router 2

PIM

router 4

Multicast packet transmission when

IGMP snooping and PIM snooping both run

Source 1 Source 2

PIM

router 1

Layer 2 switch

PIM

router 3

PIM

router 2

PIM

router 4

Receiver 1 Receiver 2

Multicast packets (S1, G1) Join message (S1, G1)

Multicast packets (S2, G2) Join message (S2, G2)

Receiver 1 Receiver 2

As shown in Figure 15, Source 1 sends multicast data to multicast group G1, and Source 2 sends multicast data to multicast group G2. Receiver 1 belongs to G1, and Receiver 2 belongs to G2. The Layer 2 switch's interfaces that connect to the PIM routers are in the same VLAN.

• When the Layer 2 switch runs only IGMP snooping, it performs the following actions: a. Maintains the router ports according to the received PIM hello messages that PIM routers

send.

b. Floods all other types of received PIM messages except PIM hello messages in the VLAN. c. Forwards all multicast data to all router ports in the VLAN.

Each PIM router in the VLAN, whether interested in the multicast data or not, can receive all multicast data and all PIM messages except PIM hello messages.

• When the Layer 2 switch runs both IGMP snooping and PIM snooping, it performs the following

actions:

a. Examines whether a PIM router is interested in the multicast data addressed to a multicast

group according to the received PIM messages that the router send.

b. Adds only the ports that connect to the router and are interested in the data to a PIM

snooping routing entry.

c. Forwards PIM messages and multicast data to only the routers that are interested in the

data, which saves network bandwidth.

For more information about IGMP snooping and the router port, see "Configuring IGMP snooping."

PIM snoo

ping can run in PIM-SM and PIM-SSM networks. Do not configure PIM snooping in

PIM-DM or BIDIR-PIM networks. For more information about PIM, see "Configuring PIM."

Configuring PIM snooping

IMPORTANT:

• Do not configure PIM snooping in secondary VLANs because PIM snooping does not take effec

in secondary VLANs. For more information about secondary VLANs, see Layer 2—LAN Switching Configuration Guide.

• Make sure the IP packet length of join/prune messages is less than the MTU of receiver-side PIM interfaces that connect to PIM snooping devices. Otherwise, multicast data might not be correctly forwarded. The IP packet length of join/prune messages is the packet length of join/prune messages plus the IP header length. To set the maximum size of join/prune

messages, use the jp-pkt-size command. To set the MTU for an Ethernet interface, use the mtu command. For more information about the command, see Interface Command Reference.

To configure PIM snooping for a VLAN, you must enable IGMP snooping globally on the Layer 2 device, and then enable IGMP snooping and PIM snooping for the VLAN.

After you enable PIM snooping for a VLAN, PIM snooping works only on the member interfaces of the VLAN.

To configure PIM snooping:

Step Command Remarks

1. Enter system view.

2. Enable IGMP snooping

globally and enter IGMP-snooping view.

3. Return to system view.

4. Enter VLAN view.

5. Enable IGMP snooping for

the VLAN.

6. Enable PIM snooping for

the VLAN.

7. (Optional.) Set the aging

time for global neighbor ports on the new active MPU after an active/standby switchover.

system-view

igmp-snooping

quit

vlan-id

interval

vlan

igmp-snooping enable

pim-snooping enable

pim-snooping graceful-restart neighbor-aging-time

N/A

By default, IGMP snooping is

disabled.

N/A

By default, IGMP snooping is disabled in a VLAN.

By default, PIM snooping is disabled in a VLAN.

The default setting is 105 seconds.

A global neighbor port is a Layer 2 aggregate interface that acts as a neighbor port.

Step Command Remarks

8. (Optional.) Set the aging

time for global downstream ports and global router ports on the new active MPU after an active/standby switchover.

pim-snooping graceful-restart join-aging-time

interval

The default setting is 210 seconds.

A global downstream port or a global router port is a Layer 2 aggregate interface that acts as a downstream port or router port.

Displaying and maintaining PIM snooping

Execute display commands in any view and reset commands in user view.

Task Command

Display PIM snooping neighbor information (in standalone mode).

display pim-snooping neighbor

slot

[

slot-number ] [

verbose

]

[

vlan

vlan-id ]

Display PIM snooping neighbor information (in IRF mode).

Display PIM snooping router port information (in standalone mode).

Display PIM snooping router port information (in IRF mode).

Display PIM snooping routing entries (in standalone mode).

Display PIM snooping routing entries (in IRF mode).

Display statistics for the PIM messages learned through PIM snooping.

Clear statistics for the PIM messages learned through PIM snooping.

display pim-snooping neighbor

chassis

[

verbose ]

[

display pim-snooping router-port

slot

[

display pim-snooping router-port

chassis

[

display pim-snooping routing-table

vlan-id ] [

display pim-snooping routing-table

vlan-id ] [ slot-number ] [

display pim-snooping statistics

reset pim-snooping statistics

chassis-number

slot-number ]

chassis-number

slot

slot-number ] [

chassis

verbose ]

chassis-number

PIM snooping configuration example

Network requirements

As shown in Figure 16:

• OSPF runs on the network.

• Source 1 sends multicast data to multicast group 224.1.1.1, and Source 2 sends multicast data

to multicast group 225.1.1.1.

• Receiver 1 belongs to multicast group 224.1.1.1, and Receiver 2 belongs to multicast group

225.1.1.1.

• Router C and Router D run IGMP on GigabitEthernet 1/0/1. Router A, Router B, Router C, and

Router D run PIM-SM.

• GigabitEthernet 1/0/2 on Router A acts as a C-BSR and a C-RP.

[

slot

slot-number ]

slot

slot-number ]

verbose

vlan

[

slot

vlan

vlan-id ]

vlan

[

]

vlan

[

Configure IGMP snooping and PIM snooping on Switch A. Then, Switch A forwards PIM protocol packets and multicast data packets to routers that connect to receivers.

Figure 16 Network diagram

Configuration procedure

1. Assign an IP address and subnet mask to each interface according to Figure 16. (Details not

shown.)

2. Configure OSPF on the routers. (Details not shown.)

3. Configure Router A:

# Enable IP multicast routing.

<RouterA> system-view [RouterA] multicast routing [RouterA-mrib] quit

# Enable PIM-SM on each interface.

[RouterA] interface gigabitethernet 1/0/1 [RouterA-GigabitEthernet1/0/1] pim sm [RouterA-GigabitEthernet1/0/1] quit [RouterA] interface gigabitethernet 1/0/2 [RouterA-GigabitEthernet1/0/2] pim sm [RouterA-GigabitEthernet1/0/2] quit

# Configure GigabitEthernet 1/0/2 as a C-BSR and a C-RP.

[RouterA] pim [RouterA-pim] c-bsr 10.1.1.1 [RouterA-pim] c-rp 10.1.1.1 [RouterA-pim] quit

4. Configure Router B:

# Enable IP multicast routing.

<RouterB> system-view [RouterB] multicast routing [RouterB-mrib] quit

# Enable PIM-SM on each interface.

[RouterB] interface gigabitethernet 1/0/1 [RouterB-GigabitEthernet1/0/1] pim sm [RouterB-GigabitEthernet1/0/1] quit [RouterB] interface gigabitethernet 1/0/2

[RouterB-GigabitEthernet1/0/2] pim sm [RouterB-GigabitEthernet1/0/2] quit

5. Configure Router C:

# Enable IP multicast routing.

<RouterC> system-view [RouterC] multicast routing [RouterC-mrib] quit

# Enable IGMP on GigabitEthernet 1/0/1.

[RouterC] interface gigabitethernet 1/0/1 [RouterC-GigabitEthernet1/0/1] igmp enable [RouterC-GigabitEthernet1/0/1] quit

# Enable PIM-SM on GigabitEthernet 1/0/2.

[RouterC] interface gigabitethernet 1/0/2 [RouterC-GigabitEthernet1/0/2] pim sm [RouterC-GigabitEthernet1/0/2] quit

6. Configure Router D:

# Enable IP multicast routing.

<RouterD> system-view [RouterD] multicast routing [RouterD-mrib] quit

# Enable IGMP on GigabitEthernet 1/0/1.

[RouterD] interface gigabitethernet 1/0/1 [RouterD-GigabitEthernet1/0/1] igmp enable [RouterD-GigabitEthernet1/0/1] quit

# Enable PIM-SM on GigabitEthernet 1/0/2.

[RouterD] interface gigabitethernet 1/0/2 [RouterD-GigabitEthernet1/0/2] pim sm [RouterD-GigabitEthernet1/0/2] quit

7. Configure Switch A:

# Enable IGMP snooping globally.

<SwitchA> system-view [SwitchA] igmp-snooping [SwitchA-igmp-snooping] quit

# Create VLAN 100, assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/4 to the VLAN, and enable IGMP snooping and PIM snooping for the VLAN.

[SwitchA] vlan 100 [SwitchA-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/4 [SwitchA-vlan100] igmp-snooping enable [SwitchA-vlan100] pim-snooping enable [SwitchA-vlan100] quit

Verifying the configuration

# On Switch A, display information about PIM snooping neighbors for VLAN 100.

[SwitchA] display pim-snooping neighbor vlan 100 Total 4 neighbors.

VLAN 100: Total 4 neighbors.

10.1.1.1

Slots (0 in total): Ports (1 in total): GE1/0/1 (00:32:43)

10.1.1.2 Slots (0 in total): Ports (1 in total): GE1/0/2 (00:32:43)

10.1.1.3 Slots (0 in total): Ports (1 in total): GE1/0/3 (00:32:43)

10.1.1.4 Slots (0 in total): Ports (1 in total): GE1/0/4 (00:32:43)

The output shows that Router A, Router B, Router C, and Router D are PIM snooping neighbors.

# On Switch A, display information about PIM snooping routing entries for VLAN 100.

[SwitchA] display pim-snooping routing-table vlan 100 Total 2 entries. FSM Flag: NI-no info, J-join, PP-prune pending

VLAN 100: Total 2 entries. (*, 224.1.1.1) Upstream neighbor: 10.1.1.1 Upstream Slots (0 in total): Upstream Ports (1 in total): GE1/0/1 Downstream Slots (0 in total): Downstream Ports (1 in total): GE1/0/3 Expires: 00:03:01, FSM: J (*, 225.1.1.1) Upstream neighbor: 10.1.1.2 Upstream Slots (0 in total): Upstream Ports (1 in total): GE1/0/2 Downstream Slots (0 in total): Downstream Ports (1 in total): GE1/0/4 Expires: 00:03:11, FSM: J

The output shows that:

• Switch A will forward the multicast data intended for multicast group 224.1.1.1 to only Router C.

• Switch A will forward the multicast data intended for multicast group 225.1.1.1 to only Router D.

Troubleshooting PIM snooping

PIM snooping does not work on a Layer 2 device

Symptom

PIM snooping does not work on a Layer 2 device.

Solution

To resolve the problem:

1. Use the display current-configuration command to display information about IGMP snooping

and PIM snooping.

2. If IGMP snooping is not enabled, enable IGMP snooping globally, and then enable IGMP

snooping and PIM snooping for the VLAN.

3. If PIM snooping is not enabled, enable PIM snooping for the VLAN.

4. If the problem persists, contact Hewlett Packard Enterprise Support.

Configuring multicast VLANs

Overview

As shown in Figure 17, Host A, Host B, and Host C are in three different VLANs and the same multicast group. When Switch A (Layer 3 device) receives multicast data for that group, it sends three copies of the multicast data to Switch B (Layer 2 device). This occupies a large amount of bandwidth and increases the burden on the Layer 3 device.

Figure 17 Multicast transmission without the multicast VLAN feature

Multicast packets

VLAN 2

VLAN 3

VLAN 4

Source

Switch A

IGMP querier

After a multicast VLAN is configured on Switch B, Switch A sends only one copy of the multicast data to the multicast VLAN on Switch B. This method saves network bandwidth and lessens the burden on the Layer 3 device.

Multicast VLANs include sub-VLAN-based multicast VLANs and port-based multicast VLANs.

Sub-VLAN-based multicast VLAN

As shown in Figure 18:

• Host A, Host B, and Host C are in VLAN 2 through VLAN 4, respectively.

• On Switch B, VLAN 10 is a multicast VLAN. VLAN 2 through VLAN 4 are sub-VLANs of VLAN

10.

• IGMP snooping is enabled for the multicast VLAN and its sub-VLANs.

VLAN 2

Receiver

Host A

VLAN 3

Receiver

Host B

Switch B

VLAN 4

Receiver

Host C

Figure 18 Sub-VLAN-based multicast VLAN

IGMP snooping manages router ports in the multicast VLAN and member ports in each sub-VLAN. When Switch A receives multicast data from the multicast source, it sends only one copy of the multicast data to the multicast VLAN on Switch B. Then, Switch B sends a separate copy to each sub-VLAN in the multicast VLAN.

Port-based multicast VLAN

As shown in Figure 19:

• Host A, Host B, and Host C are in VLAN 2 through VLAN 4, respectively.

• On Switch B, VLAN 10 is a multicast VLAN. All the user ports are hybrid ports and are assigned

to VLAN 10.

• IGMP snooping is enabled for the multicast VLAN and VLAN 2 through VLAN 4. Figure 19 Port-based multicast VLAN

Multicast packets

VLAN 10 (Multicast VLAN)

Source

IGMP snooping manages the router ports and member ports in the multicast VLAN. When Switch A receives multicast data from the multicast source, it sends only one copy of the multicast data to the multicast VLAN on Switch B. Switch B sends a separate copy to each user port in the multicast VLAN.

Switch A

IGMP querier

GE1/0/1

Switch B

GE1/0/2

GE1/0/3

GE1/0/4

VLAN 2

Receiver

Host A

VLAN 3

Receiver

Host B

VLAN 4

Receiver

Host C

Multicast VLAN configuration task list

Tasks at a glance

(Required.) Perform one of the following tasks:

• Configuring a sub-VLAN-based multicast VLAN

• Configuring a port-based multicast VLAN:

{ Configuring user port attributes { Assigning user ports to a multicast VLAN

(Optional.) Setting the maximum number of multicast VLAN forwarding entries

When you configure the multicast VLANs, follow these guidelines:

• If you have configured both a sub-VLAN-based multicast VLAN and a port-based multicast

VLAN on a device, the port-based multicast VLAN configuration takes effect.

• Do not configure a VLAN as a multicast VLAN or a multicast sub-VLAN if the VLAN interface is

enabled with PIM or IGMP. Otherwise, the system displays errors.

• Do not enable PIM or IGMP on a VLAN interface if the VLAN interface belongs to a multicast

VLAN or a multicast sub-VLAN. Otherwise, multicast forwarding exceptions occur.

• The multicast VLAN feature does not take effect on secondary VLANs. As a best practice, do

not configure the multicast VLAN feature for secondary VLANs. For more information about

—

secondary VLANs, see Layer 2

LAN Switching Configuration Guide.

Configuring a sub-VLAN-based multicast VLAN

To configure a sub-VLAN-based multicast VLAN, configure a VLAN as a multicast VLAN, and assign the VLANs that contain multicast receivers to the multicast VLAN as sub-VLANs.

Configuration prerequisites

Before you configure a sub-VLAN-based multicast VLAN, complete the following tasks:

• Create VLANs as required.

• Enable IGMP snooping for the VLAN to be configured as the multicast VLAN, and for the

VLANs to be configured as sub-VLANs.

Configuration guidelines

When you configure a sub-VLAN-based multicast VLAN, follow these guidelines:

• The VLAN to be configured as the multicast VLAN must exist.

• The VLANs to be configured as sub-VLANs of the multicast VLAN must exist and cannot be

multicast VLANs or sub-VLANs of any other multicast VLAN.

Configuration procedure

To configure a sub-VLAN-based multicast VLAN:

Step Command Remarks

1. Enter system view.

system-view

N/A

Step Command Remarks

2. Configure a VLAN as a

multicast VLAN and enter its view.

3. Assign the specified

VLANs to the multicast VLAN as sub-VLANs.

multicast-vlan

subvlan

vlan-list

vlan-id

By default, a VLAN is not a multicast VLAN.

By default, a multicast VLAN does not have any sub-VLANs.

Configuring a port-based multicast VLAN

To configure a port-based multicast VLAN, perform the following tasks:

1. Configure a VLAN as a multicast VLAN.

2. Configure the attributes for user ports that are connected to the multicast receivers.

3. Assign the user ports to the multicast VLAN.

You can assign only Layer 2 Ethernet interfaces or Layer 2 aggregate interfaces as user ports to a multicast VLAN.

Configuration prerequisites

Before you configure a port-based multicast VLAN, complete the following tasks:

• Create VLANs as required.

• Enable IGMP snooping for the VLAN to be configured as the multicast VLAN.

• Enable IGMP snooping for all the VLANs that contain the multicast receivers.

Configuring user port attributes

Step Command Remarks

1. Enter system view.

2. Enter interface view.

3. Configure the link type of

the user port as hybrid.

4. Specify the PVID of the

current user port as the VLAN to which the user port belongs.

5. Configure the current

user port to permit multicast VLAN and to untag the packets.

system-view interface

interface-number

port link-type hybrid

port hybrid pvid vlan

port hybrid vlan untagged

interface-type

vlan-id

vlan-id-list

N/A

The default setting is

For more information about this

command, see Layer 2—LAN Switching Command Reference.

By default, the PVID for a hybrid port is VLAN 1.

For more information about this

command, see Layer 2—LAN Switching Command Reference.

By default, a hybrid port permits only VLAN 1.

For more information about this

command, see Layer 2—LAN Switching Command Reference.

access

Assigning user ports to a multicast VLAN

You can assign multiple user ports to a multicast VLAN in multicast VLAN view, or assign one user port to a multicast VLAN in interface view.

When you perform this task, follow these guidelines:

• The VLAN to be configured as a multicast VLAN must exist.

• A port can be assigned to only one multicast VLAN.

Assigning ports to a multicast VLAN in multicast VLAN view

Step Command Remarks

1. Enter system view.

2. Configure a VLAN as a

multicast VLAN and enter its view.

3. Assign ports to the

multicast VLAN.

Assigning a port to a multicast VLAN in interface view

system-view

multicast-vlan

port

interface-list

vlan-id

N/A

By default, a VLAN is not a multicast VLAN.

By default, a multicast VLAN does not have any user ports.

Step Command Remarks

1. Enter system view.

2. Configure a VLAN as a

multicast VLAN and enter its view.

3. Return to system view.

4. Enter interface view.

5. Assign the current port to

the multicast VLAN.

system-view

multicast-vlan

quit interface

interface-number

port multicast-vlan

vlan-id

interface-type

vlan-id

N/A

By default, a VLAN is not a multicast VLAN.

N/A

By default, a user port does not belong to any multicast VLAN.

Setting the maximum number of multicast VLAN forwarding entries

You can set the maximum number of multicast VLAN forwarding entries on the device. When the upper limit is reached, the device does not create multicast VLAN forwarding entries until some entries age out or are manually removed.

If the total number of the entries exceeds the upper limit value that you are setting, the system does not automatically remove existing entries or create new entries. As a best practice, manually remove some entries to allow new entries to be created.

To set the maximum number of multicast VLAN forwarding entries:

Step Command Remarks

1. Enter system view.

2. Set the maximum number of

multicast VLAN forwarding entries.

system-view

multicast-vlan entry-limit

N/A

limit

By default, no limit is placed on the maximum number of multicast VLAN forwarding entries.

Displaying and maintaining multicast VLANs

Execute display commands in any view and reset commands in user view.

Task Command

Display information about multicast VLANs.

display multicast-vlan

[ vlan-id ]

Display information about multicast groups in multicast VLANs (in standalone mode).

Display information about multicast groups in multicast VLANs (in IRF mode).

Display information about multicast VLAN forwarding entries (in standalone mode).

Display information about multicast VLAN forwarding entries (in IRF mode).

Clear multicast groups in multicast VLANs.

display multicast-vlan group

vlan

subvlan

vlan

slot

slot-number |

chassis

vlan-id ] *

vlan-id |

group-address |

display multicast-vlan group

group-address |

verbose display multicast-vlan forwarding-table

mask

[

{ mask-length | mask } ] |

vlan display multicast-vlan forwarding-table

mask

[

{ mask-length | mask } ] | slot-number |

reset multicast-vlan group

{ mask-length | mask } ] | group-address [ | mask } ] |

{ mask-length | mask } ] | source-address [

vlan-id ] *

{ mask-length | mask } ] | source-address [

[ source-address |

verbose

[ source-address |

chassis-number

slot

slot-number |

chassis

chassis-number

vlan

vlan-id ] *

[ source-address [

vlan

vlan-id ] *

slot

slot-number |

[ group-address

mask

subvlan

[ group-address

mask

vlan-id |

mask

slot

mask

{ mask-length

Multicast VLAN configuration examples

Sub-VLAN-based multicast VLAN configuration example

Network requirements

As shown in Figure 20:

• IGMPv2 runs on Layer 3 device Switch A, and IGMPv2 snooping runs on Layer 2 device Switch

• Switch A acts as the IGMP querier.

• The multicast source sends multicast data to multicast group 224.1.1.1. Receivers Host A, Host

B, and Host C belong to VLAN 2, VLAN 3, and VLAN 4, respectively.

Configure a sub-VLAN-based multicast VLAN on Switch B to meet the following requirements:

• Switch A sends the multicast data to Switch B through the multicast VLAN.

• Switch B forwards the multicast data to the receivers in different user VLANs.

Figure 20 Network diagram

Configuration procedure

1. Configure Switch A:

# Enable IP multicast routing.

<SwitchA> system-view [SwitchA] multicast routing [SwitchA-mrib] quit

# Create VLAN 20, and assign GigabitEthernet 1/0/2 to the VLAN.

[SwitchA] vlan 20 [SwitchA-vlan20] port gigabitethernet 1/0/2 [SwitchA-vlan20] quit

# Assign an IP address to VLAN-interface 20, and enable PIM-DM on the interface.

[SwitchA] interface vlan-interface 20 [SwitchA-Vlan-interface20] ip address 1.1.1.2 24 [SwitchA-Vlan-interface20] pim dm [SwitchA-Vlan-interface20] quit

# Create VLAN 10.

[SwitchA] vlan 10 [SwitchA-vlan10] quit

# Configure GigabitEthernet 1/0/1 as a hybrid port, and assign it to VLAN 10 as a tagged VLAN member.

[SwitchA] interface gigabitethernet 1/0/1 [SwitchA-GigabitEthernet1/0/1] port link-type hybrid [SwitchA-GigabitEthernet1/0/1] port hybrid vlan 10 tagged [SwitchA-GigabitEthernet1/0/1] quit

# Assign an IP address to VLAN-interface 10, and enable IGMP on the interface.

[SwitchA] interface vlan-interface 10 [SwitchA-Vlan-interface10] ip address 10.110.1.1 24 [SwitchA-Vlan-interface10] igmp enable [SwitchA-Vlan-interface10] quit

2. Configure Switch B:

# Enable IGMP snooping globally.

<SwitchB> system-view [SwitchB] igmp-snooping [SwitchB-igmp-snooping] quit

# Create VLAN 2, assign GigabitEthernet 1/0/2 to the VLAN, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 2 [SwitchB-vlan2] port gigabitethernet 1/0/2 [SwitchB-vlan2] igmp-snooping enable [SwitchB-vlan2] quit

# Create VLAN 3, assign GigabitEthernet 1/0/3 to the VLAN, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 3 [SwitchB-vlan3] port gigabitethernet 1/0/3 [SwitchB-vlan3] igmp-snooping enable [SwitchB-vlan3] quit

# Create VLAN 4, assign GigabitEthernet 1/0/4 to the VLAN, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 4 [SwitchB-vlan4] port gigabitethernet 1/0/4 [SwitchB-vlan4] igmp-snooping enable [SwitchB-vlan4] quit

# Create VLAN 10, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 10 [SwitchB-vlan10] igmp-snooping enable [SwitchB-vlan10] quit

# Configure GigabitEthernet 1/0/1 as a hybrid port, and assign it to VLAN 10 as a tagged VLAN member.

[SwitchB] interface gigabitethernet 1/0/1 [SwitchB-GigabitEthernet1/0/1] port link-type hybrid [SwitchB-GigabitEthernet1/0/1] port hybrid vlan 10 tagged [SwitchB-GigabitEthernet1/0/1] quit

# Configure VLAN 10 as a multicast VLAN, and configure VLAN 2 through VLAN 4 as sub-VLANs.

[SwitchB] multicast-vlan 10 [SwitchB-mvlan-10] subvlan 2 to 4 [SwitchB-mvlan-10] quit

Verifying the configuration

# Display information about all multicast VLANs on Switch B.

[SwitchB] display multicast-vlan Total 1 multicast VLANs.

Multicast VLAN 10: Sub-VLAN list(3 in total): 2-4 Port list(0 in total):

# Display information about multicast groups in multicast VLANs on Switch B.

[SwitchB] display multicast-vlan group Total 1 entries.

Multicast VLAN 10: Total 1 entries. (0.0.0.0, 224.1.1.1) Sub-VLANs (3 in total): VLAN 2 VLAN 3 VLAN 4

The output shows that multicast group 224.1.1.1 belongs to multicast VLAN 10. Multicast VLAN 10 contains sub-VLANs VLAN 2 through VLAN 4. Switch B will replicate the multicast data of VLAN 10 to VLAN 2 through VLAN 4.

Port-based multicast VLAN configuration example

Network requirements

As shown in Figure 21:

• IGMPv2 runs on Switch A. IGMPv2 snooping runs on Switch B.

• Switch A acts as the IGMP querier.

• The multicast source sends multicast data to multicast group 224.1.1.1. Receivers Host A, Host

B, and Host C belong to VLAN 2, VLAN 3, and VLAN 4, respectively.

Configure a port-based multicast VLAN on Switch B to meet the following requirements:

• Switch A sends multicast data to Switch B through the multicast VLAN.

• Switch B forwards the multicast data to the receivers in different user VLANs.

Figure 21 Network diagram

Configuration procedure

1. Configure Switch A:

# Enable IP multicast routing globally.

<SwitchA> system-view

[SwitchA] multicast routing [SwitchA-mrib] quit

# Create VLAN 20, and assign GigabitEthernet 1/0/2 to the VLAN.

[SwitchA] vlan 20 [SwitchA-vlan20] port gigabitethernet 1/0/2 [SwitchA-vlan20] quit

# Assign an IP address to VLAN-interface 20, and enable PIM-DM on the interface.

[SwitchA] interface vlan-interface 20 [SwitchA-Vlan-interface20] ip address 1.1.1.2 24 [SwitchA-Vlan-interface20] pim dm [SwitchA-Vlan-interface20] quit

# Create VLAN 10.

[SwitchA] vlan 10 [SwitchA-vlan10] quit

# Configure GigabitEthernet 1/0/1 as a hybrid port, and assign it to VLAN 10 as a tagged VLAN member.

[SwitchA] interface gigabitethernet 1/0/1 [SwitchA-GigabitEthernet1/0/1] port link-type hybrid [SwitchA-GigabitEthernet1/0/1] port hybrid vlan 10 tagged

# Assign an IP address to VLAN-interface 10, and enable IGMP on the interface.

[SwitchA] interface vlan-interface 10 [SwitchA-Vlan-interface10] ip address 10.110.1.1 24 [SwitchA-Vlan-interface10] igmp enable [SwitchA-Vlan-interface10] quit

2. Configure Switch B:

# Enable IGMP snooping globally.

<SwitchB> system-view [SwitchB] igmp-snooping [SwitchB-igmp-snooping] quit

# Create VLAN 10, assign GigabitEthernet 1/0/1 to VLAN 10, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 10 [SwitchB-vlan10] port gigabitethernet 1/0/1 [SwitchB-vlan10] igmp-snooping enable [SwitchB-vlan10] quit

# Create VLAN 2, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 2 [SwitchB-vlan2] igmp-snooping enable [SwitchB-vlan2] quit

# Create VLAN 3, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 3 [SwitchB-vlan3] igmp-snooping enable [SwitchB-vlan3] quit

# Create VLAN 4, and enable IGMP snooping for the VLAN.

[SwitchB] vlan 4 [SwitchB-vlan4] igmp-snooping enable [SwitchB-vlan4] quit

# Configure GigabitEthernet 1/0/2 as a hybrid port, and configure VLAN 2 as the PVID of the hybrid port.

[SwitchB] interface gigabitethernet 1/0/2 [SwitchB-GigabitEthernet1/0/2] port link-type hybrid [SwitchB-GigabitEthernet1/0/2] port hybrid pvid vlan 2

# Assign GigabitEthernet 1/0/2 to VLAN 2 and VLAN 10 as an untagged VLAN member.

[SwitchB-GigabitEthernet1/0/2] port hybrid vlan 2 untagged [SwitchB-GigabitEthernet1/0/2] port hybrid vlan 10 untagged [SwitchB-GigabitEthernet1/0/2] quit

# Configure GigabitEthernet 1/0/3 as a hybrid port, and configure VLAN 3 as the PVID of the hybrid port.

[SwitchB] interface gigabitethernet 1/0/3 [SwitchB-GigabitEthernet1/0/3] port link-type hybrid [SwitchB-GigabitEthernet1/0/3] port hybrid pvid vlan 3

# Assign GigabitEthernet 1/0/3 to VLAN 3 and VLAN 10 as an untagged VLAN member.

[SwitchB-GigabitEthernet1/0/3] port hybrid vlan 3 untagged [SwitchB-GigabitEthernet1/0/3] port hybrid vlan 10 untagged [SwitchB-GigabitEthernet1/0/3] quit

# Configure GigabitEthernet 1/0/4 as a hybrid port, and configure VLAN 4 as the PVID of the hybrid port.

[SwitchB] interface gigabitethernet 1/0/4 [SwitchB-GigabitEthernet1/0/4] port link-type hybrid [SwitchB-GigabitEthernet1/0/4] port hybrid pvid vlan 4

# Assign GigabitEthernet 1/0/4 to VLAN 4 and VLAN 10 as an untagged VLAN member.

[SwitchB-GigabitEthernet1/0/4] port hybrid vlan 4 untagged [SwitchB-GigabitEthernet1/0/4] port hybrid vlan 10 untagged [SwitchB-GigabitEthernet1/0/4] quit

# Configure VLAN 10 as a multicast VLAN.

[SwitchB] multicast-vlan 10

# Assign GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3 to VLAN 10.

[SwitchB-mvlan-10] port gigabitethernet 1/0/2 to gigabitethernet 1/0/3 [SwitchB-mvlan-10] quit

# Assign GigabitEthernet 1/0/4 to VLAN 10.

[SwitchB] interface gigabitethernet 1/0/4 [SwitchB-GigabitEthernet1/0/4] port multicast-vlan 10 [SwitchB-GigabitEthernet1/0/4] quit

Verifying the configuration

# Display information about multicast VLANs on Switch B.

[SwitchB] display multicast-vlan Total 1 multicast VLANs.

Multicast VLAN 10: Sub-VLAN list(0 in total): Port list(0 in total): GE1/0/2 GE1/0/3 GE1/0/4

# Display dynamic IGMP snooping forwarding entries on Switch B.

[SwitchB] display igmp-snooping group Total 1 entries.

VLAN 10: Total 1 entries. (0.0.0.0, 224.1.1.1) Host slots (0 in total): Host ports (3 in total): GE1/0/2 (00:03:23) GE1/0/3 (00:04:07) GE1/0/4 (00:04:16)

The output shows that IGMP snooping maintains the user ports in multicast VLAN 10. Switch B will forward the multicast data of VLAN 10 through these user ports.

Configuring multicast routing and forwarding

Overview

The following tables are involved in multicast routing and forwarding:

• Multicast routing table of each multicast routing protocol, such as the PIM routing table.

• General multicast routing table that summarizes multicast routing information generated by

different multicast routing protocols. The multicast routing information from multicast sources to multicast groups are stored in a set of (S, G) routing entries.

• Multicast forwarding table that guides multicast forwarding. The optimal routing entries in the

multicast routing table are added to the multicast forwarding table.

RPF check mechanism

A multicast routing protocol relies on the existing unicast routes, MBGP routes, or static multicast routes to create multicast routing entries. When creating multicast routing entries, the multicast routing protocol uses reverse path forwarding (RPF) check to ensure the multicast data delivery along the correct path. The RPF check also helps avoid data loops.

A multicast routing protocol uses the following tables to perform an RPF check:

• Unicast routing table—Contains unicast routing information.

• MBGP multicast routing table—Contains MBGP multicast routing information.

• Static multicast routing table—Contains RPF routes that are manually configured.

MBGP multicast routing table and static multicast routing table are used for RPF check rather than

multicast routing.

RPF check process

The router performs the RPF check on a multicast packet as follows:

1. The router chooses an optimal route back to the packet source separately from the unicast,

MBGP, and static multicast routing tables.

The term "packet source" means different things in different situations:

{ For a packet that travels along the SPT, the packet source is the multicast source.

{ For a packet that travels along the RPT, the packet source is the RP.

{ For a bootstrap message originated from the BSR, the packet source is the BSR.

For more information about the concepts of SPT, RPT, source-side RPT, RP, and BSR, see "Configuring PIM."

2. The router selects one of the three optimal routes as the RPF route as follows:

{ If the router uses the longest prefix match principle, the route with the highest subnet mask

becomes the RPF route. If the routes have the same mask, the route with the highest route preference becomes the RPF route. If the routes have the same route preference, the unicast route becomes the RPF route.

For more information about the route preference, see Layer 3—IP Routing Configuration Guide.

{ If the router does not use the longest prefix match principle, the route with the highest route

preference becomes the RPF route. If the routes have the same preference, the unicast route becomes the RPF route.

The RPF route contains the RPF interface and RPF neighbor information.

{ If the RPF route is a unicast route or MBGP route, the outgoing interface is the RPF

interface and the next hop is the RPF neighbor.

{ If the RPF route is a static multicast route, the RPF interface and RPF neighbor are

specified in the route.

3. The router checks whether the packet arrived at the RPF interface. If yes, the RPF check

succeeds and the packet is forwarded. If not, the RPF check fails and the packet is discarded.

RPF check implementation in multicast

Implementing an RPF check on each received multicast packet brings a big burden to the router. The use of a multicast forwarding table is the solution to this issue. When the router creates a multicast forwarding entry for an (S, G) packet, it sets the RPF interface of the packet as the incoming interface of the (S, G) entry. After the router receives another (S, G) packet, it looks up the multicast forwarding table for a matching (S, G) entry:

• If no match is found, the router first determines the RPF route back to the packet source and the

RPF interface. Then, it creates a forwarding entry with the RPF interface as the incoming interface and makes the following judgments:

{ If the receiving interface is the RPF interface, the RPF check succeeds and the router

forwards the packet out of all the outgoing interfaces.

{ If the receiving interface is not the RPF interface, the RPF check fails and the router

discards the packet.

• If a match is found and the matching forwarding entry contains the receiving interface, the

router forwards the packet out of all the outgoing interfaces.

• If a match is found but the matching forwarding entry does not contain the receiving interface,

the router determines the RPF route back to the packet source. Then, the router performs one of the following actions:

{ If the RPF interface is the incoming interface, it means that the forwarding entry is correct

but the packet traveled along a wrong path. The packet fails the RPF check, and the router discards the packet.

{ If the RPF interface is not the incoming interface, it means that the forwarding entry has

expired. The router replaces the incoming interface with the RPF interface and matches the receiving interface against the RPF interface. If the receiving interface is the RPF interface, the router forwards the packet out of all outgoing interfaces. Otherwise, it discards the packet.

Figure 22 RPF check process

IP Routing Table on Router C

Destination/Mask

192.168.0.0/24

Source

192.168.0.1/24

Multicast packets

Interface

GE1/0/2

Router A

GE1/0/2

Router B

Router C

GE1/0/1

Receiver

As shown in Figure 22, assume that unicast routes are available on the network, MBGP is not configured, and no static multicast routes have been configured on Router C. Multicast packets travel along the SPT from the multicast source to the receivers. The multicast forwarding table on Router C contains the (S, G) entry, with GigabitEthernet 1/0/2 as the incoming interface.

• If a multicast packet arrives at Router C on GigabitEthernet 1/0/2, the receiving interface is the

incoming interface of the (S, G) entry. Router C forwards the packet out of all outgoing interfaces.

• If a multicast packet arrives at Router C on GigabitEthernet 1/0/1, the receiving interface is not

the incoming interface of the (S, G) entry. Router C searches its unicast routing table and finds that the outgoing interface to the source (the RPF interface) is GigabitEthernet 1/0/2. In this case, the (S, G) entry is correct, but the packet traveled along a wrong path. The packet fails the RPF check, and Router C discards the packet.

Static multicast routes

Depending on the application environment, a static multicast route can change an RPF route or create an RPF route.

Changing an RPF route

Typically, the topology structure of a multicast network is the same as that of a unicast network, and multicast traffic follows the same transmission path as unicast traffic does. You can configure a static multicast route for a multicast source to change the RPF route. As a result, the router creates a transmission path for multicast traffic that is different from the transmission path for unicast traffic.

Figure 23 Changing an RPF route

As shown in Figure 23, when no static multicast route is configured, Router C's RPF neighbor on the path back to the source is Router A. The multicast data from the source travels through Router A to Router C. You can configure a static multicast route on Router C and specify Router B as Router C's RPF neighbor on the path back to the source. The multicast data from the source travels along the path: Router A to Router B and then to Router C.

Creating an RPF route

When a unicast route is blocked, multicast forwarding might be stopped due to lack of an RPF route. You can configure a static multicast route to create an RPF route. In this way, a multicast routing entry is created to guide multicast forwarding.

Figure 24 Creating an RPF route

Multicast Routing Table Static on Router C

Source/Mask

Interface

RPF neighbor/Mask

OSPF domain

192.168.0.0/24

Multicast Routing Table Static on Router D

Source/Mask

192.168.0.0/24

Source

192.168.0.1/24

Multicast packets Multicast static route

GE1/0/1

Interface

GE1/0/1

RIP domain

Router A Router B Router C

1.1.1.1/24

RPF neighbor/Mask

2.2.2.2/24

GE1/0/2

1.1.1.1/24

GE1/0/1

1.1.1.2/24

Router D

GE1/0/1

2.2.2.1/24

GE1/0/2

2.2.2.2/24

Receiver

As shown in Figure 24, the RIP domain and the OSPF domain are unicast isolated from each other. The receiver hosts in the OSPF domain cannot receive the multicast packets from the multicast source in the RIP domain. You can configure a static multicast route on Router C and Router D, and specify Router B and Router C as the RPF neighbors of Router C and Router D, respectively. In this way, the receiver hosts can receive the multicast data from the multicast source.

NOTE:

static multicast route takes effect only on the multicast router on which it is configured, and will not

be advertised throughout the network or redistributed to other routers.

Multicast forwarding across unicast subnets

A network might have routers that do not support multicast protocols. When multicast data is forwarded to a router of which the next hop supports only unicast protocols, the forwarding path is blocked. To implement multicast forwarding across unicast subnets, you can establish a tunnel between the multicast routers at the edges of the two unicast subnets.

Figure 25 Multicast data transmission through a tunnel

As shown in Figure 25, a tunnel is established between multicast routers Router A and Router B. Router A encapsulates multicast data in unicast IP packets, and forwards them to Router B across

the tunnel through unicast routers. Then, Router B strips off the unicast IP header and continues to forward the multicast data to the receiver.

To use this tunnel only for multicast traffic, configure static multicast routes instead of static unicast routes at the two ends of the tunnel.

Configuration task list

Tasks at a glance

(Required.) Enabling IP multicast routing

(Optional.) Configuring multicast routing and forwarding:

• (Optional.) Configuring static multicast routes

• (Optional.) Specifying the longest prefix match principle

• (Optiona

• (Optional.) Configuring a multicast forwarding boundary

• (Optional.) Configuring static multicast MAC address entries

• (Optiona

NOTE:

The device can route and forward multicast data only through the primary IP addresses of interfaces, rather than their secondary addresses or unnumbered IP addresses. For more

information about primary and secondary IP addresses, and IP unnumbered, see Layer 3—IP Services Configuration Guide.

l.) Configuring multicast load splitting

l.) Enabling multicast forwarding between sub-VLANs of a super VLAN

Enabling IP multicast routing

Enable IP multicast routing before you configure any Layer 3 multicast functionality on the public network or VPN instance.

To enable IP multicast routing:

Step Command Remarks

1. Enter system view.

2. Enable IP multicast routing

and enter MRIB view.

system-view multicast routing

vpn-instance

[

vpn-instance-name ]

N/A

By default, IP multicast routing is disabled.

Configuring multicast routing and forwarding

Before you configure multicast routing and forwarding, complete the following tasks:

• Configure a unicast routing protocol so that all devices in the domain are interoperable at the

network layer.

• Enable PIM-DM or PIM-SM.

Configuring static multicast routes

To configure a static multicast route for a given multicast source, you can specify an RPF interface or an RPF neighbor for the multicast traffic from that source.

To configure a static multicast route:

Step Command Remarks

1. Enter system view.

system-view

N/A

2. Configure a static

multicast route.

3. (Optional.) Delete static

multicast routes.

ip rpf-route-static

vpn-instance-name ] source-address { mask-length | mask } { rpf-nbr-address | interface-type interface-number }

preference

[

• Delete a specific static multicast route:

undo ip rpf-route-static [ vpn-instance

vpn-instance-name ] source-address { mask-length | mask } { rpf-nbr-address | interface-type interface-number }

• Delete all static multicast routes:

delete ip rpf-route-static [ vpn-instance

vpn-instance-name ]

preference ]

vpn-instance

[

Specifying the longest prefix match principle

You can enable the device to use the longest prefix match principle for RPF route selection. For more information about RPF route selection, see "RPF check process."

o specify the longest prefix match principle:

By default, static multicast routes do not exist.

N/A

Step Command Remarks

1. Enter system view.

2. Enter MRIB view.

3. Specify the longest prefix

match principle.

system-view multicast routing

vpn-instance

[

vpn-instance-name ]

longest-match

Configuring multicast load splitting

You can enable the device to split multiple data flows on a per-source basis or on a per-source-and-group basis. This optimizes the traffic delivery.

To configure multicast load splitting:

Step Command Remarks

1. Enter system view.

2. Enter MRIB view.

system-view multicast routing

vpn-instance

[

vpn-instance-name ]

N/A

By default, the route preference principle is used.

N/A

Step Command Remarks

By default, load splitting is

3. Configure multicast load

splitting.

load-splitting source-group

source

{

}

disabled.

This command does not take effect on BIDIR-PIM.

Configuring a multicast forwarding boundary

You can configure an interface as a multicast forwarding boundary for a multicast group range. The interface cannot receive or forward multicast packets for the group range.

To configure a multicast forwarding boundary:

Step Command Remarks

1. Enter system view.

system-view

N/A

2. Enter interface view.

3. Configure the interface as a

multicast forwarding boundary for a multicast group range.

interface

interface-number

multicast boundary

group-address { mask-length | mask }

interface-type

N/A

By default, the interface is not configured as a multicast forwarding boundary.

Configuring static multicast MAC address entries

In Layer 2 multicast, multicast MAC address entries can be dynamically created or added through Layer 2 multicast protocols (such as IGMP snooping). You can also manually configure static multicast MAC address entries by binding multicast MAC addresses and ports to control the destination ports of the multicast data.

TIP:

The multicast MAC address that can be manually configured in the multicast MAC address entry must be unused. (A multicast MAC address is the MAC address in which the least significant bit of the most significant octet is 1.)

You can configure static multicast MAC address entries on the specified interfaces in system view or on the current interface in interface view.

Configuring a static multicast MAC address entry in system view

Step Command Remarks

1. Enter system view.

2. Configure a static multicast

MAC address entry.

system-view mac-address multicast

mac-address interface-list

interface

vlan

vlan-id

N/A

By default, static multicast MAC address entries do not exist.

Configuring a static multicast MAC address entry in interface view

Step Command Remarks

1. Enter system view.

system-view

N/A

Step Command Remarks

2. Enter Layer 2 Ethernet

interface/Layer 2 aggregate interface view.

interface

interface-number

interface-type

N/A

3. Configure a static multicast

MAC address entry.

mac-address multicast

mac-address

vlan

vlan-id

By default, static multicast MAC address entries do not exist.

Enabling multicast forwarding between sub-VLANs of a super VLAN

A super VLAN is associated with multiple sub-VLANs. Sub-VLANs are isolated with each other at

Layer 2. For information about the super VLAN and sub-VLANs, see Layer 2—LAN Switching Configuration Guide.

To enable multicast forwarding between sub-VLANs that are associated with a super VLAN:

Step Command Remarks

1. Enter system view.

2. Enter VLAN interface view.

3. Enable multicast forwarding

between sub-VLANs that are associated with a super VLAN.

4. Clear all multicast

forwarding entries with the super VLAN interface as the incoming interface.

system-view interface vlan-interface

interface-number

multicast forwarding supervlan community

reset multicast [ vpn-instance

vpn-instance-name ]

forwarding-table

{ { source-address [ { mask-length | mask } ] | group-address [ { mask-length | mask } ] |

incoming-interface

{ interface-type interface-number } } * |

mask

all

N/A

By default, multicast data cannot be forwarded among sub-VLANs of a super VLAN.

N/A

}

Displaying and maintaining multicast routing and forwarding

CAUTION:

The reset commands might cause multicast data transmission failures.

Execute display commands in any view and reset commands in user view.

Task Command

Display static multicast MAC address entries.

Display information about interfaces maintained by the MRIB.

display mac-address

multicast

[

display mrib [ vpn-instance

[ interface-type interface-number ]

] [

vlan

[ mac-address [

vlan-id ] [

count

vpn-instance-name ]

vlan

vlan-id ] |

] ]

interface

Task Command

Display multicast boundary information.

Display DF information (in standalone mode).

Display DF information (in IRF mode).

Display statistics for multicast forwarding events (in standalone mode).

Display statistics for multicast forwarding events (in IRF mode).

Display multicast forwarding entries (in standalone mode).

Display multicast forwarding entries (in IRF mode).

display multicast [ vpn-instance boundary

interface-type interface-number ]

display multicast forwarding df-info

slot-number ]

display multicast forwarding df-info

chassis-number

display multicast [ vpn-instance forwarding event [ slot

display multicast [ vpn-instance forwarding event [ chassis

slot-number ]

display multicast forwarding-table

mask } ] | group-address [

incoming-interface outgoing-interface

interface-type interface-number |

statistics display multicast

forwarding-table

mask } ] | group-address [

chassis incoming-interface outgoing-interface

interface-type interface-number |

[ group-address [ mask-length | mask ] ] [

vpn-instance

[

[ rp-address ] [

vpn-instance

[

[ rp-address ] [

slot

slot-number ]

chassis-number

vpn-instance

[

[ source-address [

mask

{ mask-length | mask } ] |

interface-type interface-number |

exclude | include | match

{

] *

vpn-instance

[

[ source-address [

mask

{ mask-length | mask } ] |

chassis-number

slot

slot-number |

interface-type interface-number |

exclude | include | match

{

vpn-instance-name ]

interface

vpn-instance-name ]

verbose

vpn-instance-name ]

verbose

vpn-instance-name ]

mask

slot

slot-number |

vpn-instance-name ]

mask

statistics

slot

] [

chassis

] [

slot

{ mask-length |

}

{ mask-length |

}

] *

Display information about the DF list in the multicast forwarding table (in standalone mode).

Display information about the DF list in the multicast forwarding table (in IRF mode).

Display multicast routing entries.

Display static multicast routing entries.

Display RPF information for a multicast source.

Clear statistics for multicast forwarding events.

Clear multicast forwarding entries.

display multicast forwarding-table df-list

slot-number ]

display multicast forwarding-table df-list

chassis

[

display multicast [ vpn-instance routing-table

mask } ] | group-address [

incoming-interface outgoing-interface

interface-type interface-number ] *

display multicast [ vpn-instance routing-table static

mask } ]

display multicast [ vpn-instance rpf-info

reset multicast forwarding event

reset multicast forwarding-table

mask } ] | group-address [

incoming-interface all

chassis-number

source-address [ group-address ]

}

vpn-instance

[

[ group-address ] [

vpn-instance

[

[ group-address ] [

slot

slot-number ]

[ source-address [

mask

{ mask-length | mask } ] |

interface-type interface-number |

exclude | include | match

{

[ source-address { mask-length |

vpn-instance

[

vpn-instance

[

{ { source-address [

{ interface-type interface-number } } * |

vpn-instance-name ]

mask

{ mask-length | mask } ] |

vpn-instance-name ]

verbose

vpn-instance-name ]

verbose

vpn-instance-name ]

mask

{ mask-length |

}

vpn-instance-name ]

mask

{ mask-length |

] [

]

slot

Task Command

Clear multicast routing entries.

NOTE:

reset multicast routing-table

mask } ] | group-address [

incoming-interface

vpn-instance

[

{ { source-address [

interface-type interface-number } * |

vpn-instance-name ]

mask

{ mask-length |

mask

{ mask-length | mask } ] |

• When a routing entry is cleared, the associated forwarding entry is also cleared.

• When a forwarding entry is cleared, the associated routing entry is also cleared.

Multicast routing and forwarding configuration examples

Changing an RPF route

Network requirements

As shown in Figure 26:

• PIM-DM runs on the network.

• All switches on the network support multicast.

• Switch A, Switch B and Switch C run OSPF.

• Typically, the receiver host can receive the multicast data from Source through the path: Switch

A to Switch B, which is the same as the unicast route.

all

}

Configure the switches so that the multicast data from Source travels to the receiver through the path: Switch A to Switch C to Switch B. This is different from the unicast route.

Figure 26 Network diagram

Switch C

Vlan-int103

40.1.1.1/24

Vlan-int103

40.1.1.2/24

Switch A Switch B

Vlan-int200

50.1.1.1/24

Multicast static route

Vlan-int102

30.1.1.2/24

Source Receiver

50.1.1.100/24 10.1.1.100/24

PIM-DM

Vlan-int101

20.1.1.2/24

Vlan-int102

30.1.1.1/24

Vlan-int101

20.1.1.1/24

Vlan-int100

10.1.1.1/24

Configuration procedure

1. Assign an IP address and subnet mask for each interface according to Figure 26. (Details not

shown.)

2. Configure OSPF on the switches in the PIM-DM domain. (Details not shown.)

3. Enable IP multicast routing, and enable IGMP and PIM-DM:

# On Switch B, enable IP multicast routing.

<SwitchB> system-view [SwitchB] multicast routing [SwitchB-mrib] quit

# Enable IGMP on the receiver-side interface (VLAN-interface 100).

[SwitchB] interface vlan-interface 100 [SwitchB-Vlan-interface100] igmp enable [SwitchB-Vlan-interface100] quit

# Enable PIM-DM on other interfaces.

[SwitchB] interface vlan-interface 101 [SwitchB-Vlan-interface101] pim dm [SwitchB-Vlan-interface101] quit [SwitchB] interface vlan-interface 102 [SwitchB-Vlan-interface102] pim dm [SwitchB-Vlan-interface102] quit

# On Switch A, enable IP multicast routing, and enable PIM-DM on each interface.

<SwitchA> system-view [SwitchA] multicast routing [SwitchA-mrib] quit [SwitchA] interface vlan-interface 200 [SwitchA-Vlan-interface200] pim dm [SwitchA-Vlan-interface200] quit [SwitchA] interface vlan-interface 102 [SwitchA-Vlan-interface102] pim dm [SwitchA-Vlan-interface102] quit [SwitchA] interface vlan-interface 103 [SwitchA-Vlan-interface103] pim dm [SwitchA-Vlan-interface103] quit

# Enable IP multicast routing and PIM-DM on Switch C in the same way Switch A is configured. (Details not shown.)

4. Display the RPF route to Source on Switch B.

[SwitchB] display multicast rpf-info 50.1.1.100 RPF information about source 50.1.1.100: RPF interface: Vlan-interface102, RPF neighbor: 30.1.1.2 Referenced route/mask: 50.1.1.0/24 Referenced route type: igp Route selection rule: preference-preferred Load splitting rule: disable

The output shows that the current RPF route on Switch B is contributed by a unicast routing protocol and the RPF neighbor is Switch A.

5. On Switch B, configure a static multicast route to multicast source 50.1.1.100 and specify

VLAN-interface 101 on Switch C as the RPF neighbor.

[SwitchB] ip rpf-route-static 50.1.1.100 24 20.1.1.2

Verifying the configuration

# Display RPF information for the source on Switch B.

[SwitchB] display multicast rpf-info 50.1.1.100 RPF information about source 50.1.1.100: RPF interface: Vlan-interface101, RPF neighbor: 20.1.1.2 Referenced route/mask: 50.1.1.0/24 Referenced route type: multicast static Route selection rule: preference-preferred Load splitting rule: disable

The output shows that:

• The RPF route on Switch B is the configured static multicast route.

• The RPF neighbor of Switch B is Switch C.

Creating an RPF route

Network requirements

As shown in Figure 27:

• PIM-DM runs on the network.

• All switches on the network support IP multicast.

• Switch B and Switch C run OSPF, and have no unicast routes to Switch A.

• Typically, the receiver host receives the multicast data from Source 1 in the OSPF domain.

Configure the switches so that the receiver host receives multicast data from Source 2, which is outside the OSPF domain.

Figure 27 Network diagram

Configuration procedure

1. Assign an IP address and subnet mask for each interface according to Figure 27. (Details not

shown.)

2. Configure OSPF on Switch B and Switch C. (Details not shown.)

3. Enable IP multicast routing, and enable IGMP and PIM-DM:

# On Switch C, enable IP multicast routing.

<SwitchC> system-view [SwitchC] multicast routing [SwitchC-mrib] quit

# Enable IGMP on the receiver-side interface (VLAN-interface 100).

[SwitchC] interface vlan-interface 100 [SwitchC-Vlan-interface100] igmp enable [SwitchC-Vlan-interface100] quit

# Enable PIM-DM on VLAN-interface 101.

[SwitchC] interface vlan-interface 101 [SwitchC-Vlan-interface101] pim dm [SwitchC-Vlan-interface101] quit

# On Switch A, enable IP multicast routing, and enable PIM-DM on each interface.

<SwitchA> system-view [SwitchA] multicast routing [SwitchA-mrib] quit [SwitchA] interface vlan-interface 300 [SwitchA-Vlan-interface300] pim dm [SwitchA-Vlan-interface300] quit [SwitchA] interface vlan-interface 102 [SwitchA-Vlan-interface102] pim dm [SwitchA-Vlan-interface102] quit

# Enable IP multicast routing and PIM-DM on Switch B in the same way Switch A is configured. (Details not shown.)

4. Display information about their RPF routes to Source 2 on Switch B and Switch C.

[SwitchB] display multicast rpf-info 50.1.1.100 [SwitchC] display multicast rpf-info 50.1.1.100

No output is displayed because no RPF routes to Source 2 exist on Switch B or Switch C.

5. Configure a static multicast route:

# On Switch B, configure a static multicast route to Source 2 and specify VLAN-interface 102 on Switch A as the RPF neighbor.

[SwitchB] ip rpf-route-static 50.1.1.100 24 30.1.1.2

# On Switch B, configure a static multicast route to Source 2 and specify VLAN-interface 101 on Switch B as the RPF neighbor.

[SwitchC] ip rpf-route-static 50.1.1.100 24 20.1.1.2

Verifying the configuration

# Display RPF information for Source 2 on Switch B.

[SwitchB] display multicast rpf-info 50.1.1.100 RPF information about source 50.1.1.100: RPF interface: Vlan-interface102, RPF neighbor: 30.1.1.2 Referenced route/mask: 50.1.1.0/24 Referenced route type: multicast static Route selection rule: preference-preferred Load splitting rule: disable

# Display RPF information for Source 2 on Switch C.

[SwitchC] display multicast rpf-info 50.1.1.100 RPF information about source 50.1.1.100: RPF interface: Vlan-interface101, RPF neighbor: 20.1.1.2

Referenced route/mask: 50.1.1.0/24 Referenced route type: multicast static Route selection rule: preference-preferred Load splitting rule: disable

The output shows that the RPF routes to Source 2 exist on Switch B and Switch C. The routes are the configured static routes.

Multicast forwarding over a GRE tunnel

Network requirements

As shown in Figure 28:

• Multicast routing and PIM-DM are enabled on Switch A and Switch C.

• Switch B does not support multicast.

• Switch A, Switch B, and Switch C run OSPF.

Configure the switches so that the receiver host can receive the multicast data from the source.

Figure 28 Network diagram

Configuration procedure

1. Assign an IP address and subnet mask for each interface, as shown in Figure 28. (Details not

shown.)

2. Configure OSPF on all the switches. (Details not shown.)

3. Configure a GRE tunnel:

# On Switch A, create service loopback group 1, and specify the unicast tunnel service for the group.

<SwitchA> system-view [SwitchA] service-loopback group 1 type tunnel

# Add GigabitEthernet 1/0/3 to service loopback group 1. (GigabitEthernet 1/0/3 does not belong to VLAN 100 or VLAN 101.)

[SwitchA] interface gigabitethernet 1/0/3 [SwitchA-GigabitEthernet1/0/3] port service-loopback group 1 [SwitchA-GigabitEthernet1/0/3] quit

# Create a GRE tunnel interface Tunnel 1, and specify the tunnel mode as GRE/IPv4.

[SwitchA] interface tunnel 1 mode gre

# Assign an IP address to interface Tunnel 1, and specify its source and destination addresses.

[SwitchA-Tunnel1] ip address 50.1.1.1 24

[SwitchA-Tunnel1] source 20.1.1.1 [SwitchA-Tunnel1] destination 30.1.1.2 [SwitchA-Tunnel1] quit

# On Switch C, create service loopback group 1, and specify the unicast tunnel service for the group.

<SwitchC> system-view [SwitchC] service-loopback group 1 type tunnel

# Add GigabitEthernet 1/0/3 to service loopback group 1. GigabitEthernet 1/0/3 does not belong to VLAN 200 or VLAN 102.

[SwitchC] interface gigabitethernet 1/0/3 [SwitchC-GigabitEthernet1/0/3] port service-loopback group 1 [SwitchC-GigabitEthernet1/0/3] quit

# Create a GRE tunnel interface Tunnel 1, and specify the tunnel mode as GRE/IPv4.

[SwitchC] interface tunnel 1 mode gre

# Assign an IP address for interface Tunnel 1, and specify its source and destination addresses.

[SwitchC-Tunnel1] ip address 50.1.1.2 24 [SwitchC-Tunnel1] source 30.1.1.2 [SwitchC-Tunnel1] destination 20.1.1.1 [SwitchC-Tunnel1] quit

4. Enable IP multicast routing, PIM-DM, and IGMP:

# On Switch A, enable IP multicast routing.

[SwitchA] multicast routing [SwitchA-mrib] quit

# Enable PIM-DM on each interface.

[SwitchA] interface vlan-interface 100 [SwitchA-Vlan-interface100] pim dm [SwitchA-Vlan-interface100] quit [SwitchA] interface vlan-interface 101 [SwitchA-Vlan-interface101] pim dm [SwitchA-Vlan-interface101] quit [SwitchA] interface tunnel 1 [SwitchA-Tunnel1] pim dm [SwitchA-Tunnel1] quit

# On Switch C, enable IP multicast routing.

[SwitchC] multicast routing [SwitchC-mrib] quit

# Enable IGMP on the receiver-side interface (VLAN-interface 200).

[SwitchC] interface vlan-interface 200 [SwitchC-Vlan-interface200] igmp enable [SwitchC-Vlan-interface200] quit

# Enable PIM-DM on VLAN-interface 102.

[SwitchC] interface vlan-interface 102 [SwitchC-Vlan-interface102] pim dm [SwitchC-Vlan-interface102] quit

# Enable PIM-DM on Tunnel 1.

[SwitchC] interface tunnel 1 [SwitchC-Tunnel1] pim dm [SwitchC-Tunnel1] quit

5. On Switch C, configure a static multicast route to the source and specify Switch A as the RPF

neighbor.

[SwitchC] ip rpf-route-static 50.1.1.0 24 50.1.1.1

Verifying the configuration

# Send an IGMP report from Receiver to join multicast group 225.1.1.1. (Details not shown.)

# Send multicast data from Source to multicast group 225.1.1.1. (Details not shown.)

# Display PIM routing entries on Switch C.

[SwitchC] display pim routing-table Total 1 (*, G) entry; 1 (S, G) entry

(*, 225.1.1.1) Protocol: pim-dm, Flag: WC UpTime: 00:04:25 Upstream interface: NULL Upstream neighbor: NULL RPF prime neighbor: NULL Downstream interface(s) information: Total number of downstreams: 1 1: Vlan-interface200 Protocol: igmp, UpTime: 00:04:25, Expires: -

(10.1.1.100, 225.1.1.1) Protocol: pim-dm, Flag: ACT UpTime: 00:06:14 Upstream interface: Tunnel1 Upstream neighbor: 50.1.1.1 RPF prime neighbor: 50.1.1.1 Downstream interface(s) information: Total number of downstreams: 1 1: Vlan-interface200 Protocol: pim-dm, UpTime: 00:04:25, Expires: -

The output shows that Switch A is the RPF neighbor of Switch C and the multicast data from Switch A is delivered over the GRE tunnel to Switch C.

Troubleshooting multicast routing and forwarding

Static multicast route failure

Symptom

No dynamic routing protocol is enabled on the routers, and the physical status and link layer status of interfaces are both up, but the static multicast route fails.

Solution

To resolve the problem:

1. Use the display multicast routing-table static command to display information about static

multicast routes. Verify that the static multicast route has been correctly configured and that the route entry exists in the static multicast routing table.

2. Check the type of the interface that connects the static multicast route to the RPF neighbor. If

the interface is not a point-to-point interface, make sure that you specify the address of the RPF neighbor.

3. If the problem persists, contact Hewlett Packard Enterprise Support.

Configuring IGMP

Overview

Internet Group Management Protocol (IGMP) establishes and maintains the multicast group memberships between a Layer 3 multicast device and the hosts on the directly connected subnet.

IGMP has the following versions:

• IGMPv1 (defined by RFC 1112).

• IGMPv2 (defined by RFC 2236).

• IGMPv3 (defined by RFC 3376).

All IGMP versions support the ASM model. IGMPv3 can directly implement the SSM model. IGMPv1 and IGMPv2 must work with the IGMP SSM mapping feature to implement the SSM model. For more information about the ASM and SSM models, see "Multicast overview."

IGMPv1 overview

IGMPv1 manages multicast group memberships based on the query and response mechanism.

All routers that run IGMP on the same subnet can get IGMP membership report messages (often called reports) from hosts. However, only one router can act as the IGMP querier to send IGMP query messages (often called queries). The querier election mechanism determines which router acts as the IGMP querier on the subnet.

In IGMPv1, the DR elected by the multicast routing protocol (such as PIM) acts as the IGMP querier. For more information about DR, see "Configuring PIM."

Figure 29

IGMP queries and reports

As shown in Figure 29, Host B and Host C are interested in the multicast data addressed to the multicast group G1. Host A is interested in the multicast data addressed to G2. The following process describes how the hosts join the multicast groups and how the IGMP querier (Router B in Figure 29) maintains the multicast g

roup memberships:

1. The hosts send unsolicited IGMP reports to the multicast groups they want to join without

having to wait for the IGMP queries from the IGMP querier.

2. The IGMP querier periodically multicasts IGMP queries (with the destination address of

224.0.0.1) to all hosts and routers on the local subnet.

After receiving a query message, the host whose delay timer expires first sends an IGMP report to the multicast group G1 to announce its membership for G1. In this example, Host B sends the report message. Host C suppresses its own report for G1 after receiving the report from Host B. Because IGMP routers already know that G1 has at least one member, other members do not need to report their memberships. This host IGMP report suppression mechanism helps reduce traffic on the local subnet.

3. At the same time, Host A sends a report to the multicast group G2 after receiving a query.

4. Through the query and response process, the IGMP routers (Router A and Router B) determine

that the local subnet has members of G1 and G2. The multicast routing protocol (PIM, for example) on the routers generates (*, G1) and (*, G2) multicast forwarding entries, where asterisk (*) represents any multicast source. These entries are the basis for subsequent multicast forwarding.

5. When the multicast data addressed to G1 or G2 reaches an IGMP router, the router looks up

the multicast forwarding table. Based on the (*, G1) or (*, G2) entries, the router forwards the multicast data to the local subnet. Then, the receivers on the subnet can receive the data.

IGMPv1 does not define a leave group message (often called a leave message). When an IGMPv1 host is leaving a multicast group, it stops sending reports to that multicast group. If the subnet has no members for a multicast group, the IGMP routers will not receive any report addressed to that multicast group. In this case, the routers clear the information for that multicast group after a period of time.

IGMPv2 enhancements

Backwards-compatible with IGMPv1, IGMPv2 has introduced a querier election mechanism and a leave-group mechanism.

Querier election mechanism

In IGMPv1, the DR elected by the Layer 3 multicast routing protocol (such as PIM) acts as the querier.

IGMPv2 introduced an independent querier election mechanism. The querier election process is as follows:

1. Initially, every IGMPv2 router assumes itself to be the querier. Each router sends IGMP general

query messages (often called general queries) to all hosts and routers on the local subnet. The destination address of general queries is 224.0.0.1.

2. After receiving a general query, every IGMPv2 router compares the source IP address of the

query message with its own interface address. The router with the lowest IP address becomes the querier. All the other IGMPv2 routers become non-queriers.

3. All the non-queriers start the other querier present timer. If a router receives an IGMP query

from the querier before the timer expires, it resets this timer. Otherwise, the router considers that the querier has timed out. In this case, the router initiates a new querier election process.

"Leave group" mechanism

In IGMPv1, when a host leaves a multicast group, it does not send any notification to the multicast routers. The multicast routers determine whether a group has members by using the maximum response time. This adds to the leave latency.

In IGMPv2, when a host is leaving a multicast group, the following process occurs:

1. The host sends a leave message to all routers on the local subnet. The destination address of

leave messages is 224.0.0.2.

2. After receiving the leave message, the querier sends a configurable number of IGMP

group-specific queries to the group that the host is leaving. Both the destination address field and the group address field of the message are the address of the multicast group that is being queried.

3. One of the remaining members (if any on the subnet) in the group should send a report within

the maximum response time advertised in the group-specific queries.

4. If the querier receives a report for the group before the maximum response timer expires, it

maintains the memberships for the group. Otherwise, the querier assumes that the local subnet has no member hosts for the group and stops maintaining the memberships for the group.

IGMPv3 enhancements

IGMPv3 is based on and is compatible with IGMPv1 and IGMPv2. It enhances the control capabilities of hosts and the query and report capabilities of IGMP routers.

Enhancements in control capability of hosts

IGMPv3 introduced two source filtering modes (Include and Exclude). These modes allow a host to join a designated multicast group and to choose whether to receive or reject multicast data from the specified multicast sources. When a host joins a multicast group, one of the following occurs:

• If the host expects to receive multicast data from specific sources like S1, S2, …, it sends a

report with the Filter-Mode denoted as "Include Sources (S1, S2, …)."

• If the host expects to reject multicast data from specific sources like S1, S2, …, it sends a report

with the Filter-Mode denoted as "Exclude Sources (S1, S2, …)."

As shown in Figure 30, the network ha Both of these sources can send multicast data to the multicast group G. Host B wants to receive the multicast data addressed to G from Source 1 but not from Source 2.

Figure 30 Flow paths of source-and-group-specific multicast traffic

In IGMPv1 or IGMPv2, Host B cannot select multicast sources when it joins the multicast group G. The multicast streams from both Source 1 and Source 2 flow to Host B whether or not it needs them.

s two multicast sources: Source 1 (S1) and Source 2 (S2).

In IGMPv3, Host B can explicitly express that it needs to receive the multicast data that Source 1 sends to the multicast group G (denoted as (S1, G)). It also can explicitly express that it does not want to receive the multicast data that Source 2 sends to multicast group G (denoted as (S2, G)). As a result, Host B receives only multicast data from Source 1.

Enhancements in query and report capabilities

IGMPv3 introduces IGMP group-and-source queries and IGMP reports carrying group records.

• Query message carrying the source addresses

IGMPv3 is compatible with IGMPv1 and IGMPv2 and supports IGMP general queries and IGMP group-specific queries. It also introduces IGMP group-and-source-specific queries.

{ A general query does not carry a group address or a source address.

{ A group-specific query carries a group address, but no source address.

{ A group-and-source-specific query carries a group address and one or more source

addresses.

• Reports containing multiple group records

Unlike an IGMPv1 or IGMPv2 report, an IGMPv3 report is destined to 224.0.0.22 and contains one or more group records. Each group record contains a multicast group address and a multicast source address list.

Group records include the following categories:

{ IS_IN—The current filtering mode is Include. The report sender requests the multicast data

only from the sources specified in the Source Address field.

{ IS_EX—The current filtering mode is Exclude. The report sender requests the multicast

data from any sources except those specified in the Source Address field.

{ TO_IN—The filtering mode has changed from Exclude to Include. { TO_EX—The filtering mode has changed from Include to Exclude. { ALLOW—The Source Address field contains a list of additional sources from which the

receiver wants to obtain data. If the current filtering mode is Include, these sources are added to the multicast source list. If the current filtering mode is Exclude, these sources are deleted from the multicast source list.

{ BLOCK—The Source Address field contains a list of the sources from which the receiver no

longer wants to obtain data. If the current filtering mode is Include, these sources are deleted from the multicast source list. If the current filtering mode is Exclude, these sources are added to the multicast source list.

IGMP SSM mapping

An IGMPv3 host can explicitly specify multicast sources in its IGMPv3 reports. From the reports, the IGMP router can obtain the multicast source addresses and directly provide the SSM service. However, an IGMPv1 or IGMPv2 host cannot specify multicast sources in its IGMPv1 or IGMPv2 reports.

The IGMP SSM mapping feature enables the IGMP router to provide SSM support for IGMPv1 or IGMPv2 receiver hosts. The router translates (*, G) in IGMPv1 or IGMPv2 reports into (G, INCLUDE, (S1, S2...)) based on the configured IGMP SSM mappings.

The IGMP SSM mapping feature does not process IGMPv3 reports.

Figure 31 IGMP SSM mapping

As shown in Figure 31, on an SSM network, Host A, Host B, and Host C run IGMPv1, IGMPv2, and IGMPv3, respectively. To provide the SSM service for Host A and Host B, you must configure the IGMP SSM mapping feature on Router A.

After IGMP SSM mappings are configured, Router A checks the multicast group address G in the received IGMPv1 or IGMPv2 report, and performs the following operations:

• If G is not in the SSM group range, Router A provides the ASM service.

• If G is in the SSM group range but does not match any IGMP SSM mappings, Router A drops

the message.

• If G is in the SSM group range and matches IGMP SSM mappings, Router A translates (*, G) in

the report into (G, INCLUDE, (S1, S2...)) to provide SSM services.

For more information about SSM group ranges, see "Configuring PIM."

IGMP support for VPNs

IGMP maintains group memberships on a per-interface base. After receiving an IGMP message on an interface, IGMP processes the packet within the VPN to which the interface belongs. IGMP only communicates with other multicast protocols within the same VPN instance.

Protocols and standards

• RFC 1112, Host Extensions for IP Multicasting

• RFC 2236, Internet Group Management Protocol, V ersion 2

• RFC 3376, Internet Group Management Protocol, V ersion 3

IGMP configuration task list

Tasks at a glance

Configuring basic IGMP features:

• (Required.) Enabling IGMP

• (Optiona

• (Optional.) Configuring a static group member

• (Optional.) Configuring a multicast group policy

Adjusting IGMP performance:

(Optional.) Configuring IGMP query and response parameters

(Optional.) Enabling fast-leave processing

(Optional.) Enabling IGMP NSR

(Optional.) Configuring IGMP SSM mappings

l.) Specifying an IGMP version

Configuring basic IGMP features

Before you configure basic IGMP features, complete the following tasks:

• Configure any unicast routing protocol so that all devices can interoperate at the network layer.

• Configure PIM.

• Determine the IGMP version.

• Determine the multicast group and multicast source addresses for static group member

configuration.

• Determine the ACL to be used by the multicast group policy.

Enabling IGMP

Enable IGMP on the interface where the multicast group memberships are established and maintained.

To enable IGMP:

Step Command Remarks

1. Enter system view.

2. Enable IP multicast routing

and enter MRIB view.

3. Return to system view.

system-view multicast routing

vpn-instance

[

vpn-instance-name ]

quit

N/A

By default, IP multicast is disabled.

N/A

4. Enter interface view.

5. Enable IGMP.

interface

interface-number

igmp enable

interface-type

N/A

By default, IGMP is disabled.

Specifying an IGMP version

For IGMP to operate correctly, you must specify the same IGMP version for all routers on the same subnet.

To specify an IGMP version:

Step Command Remarks

1. Enter system view.

system-view

N/A

2. Enter interface view.

3. Specify an IGMP version.

interface

interface-number

igmp version

interface-type

version-number

Configuring a static group member

You can configure an interface as a static group member of a multicast group. The interface can always receive multicast data addressed to the specified multicast group.

A static group member does not respond to IGMP queries. When you complete or cancel this configuration on an interface, the interface does not send an unsolicited IGMP report or leave message. This is because the interface is not a real member host of the multicast group.

Configuration restrictions and guidelines

The interface to be configured as a static group member has the following restrictions:

• If the interface is IGMP and PIM-SM enabled, it must be a PIM-SM DR.

• If the interface is IGMP enabled but not PIM-SM enabled, it must be an IGMP querier.

For more information about PIM-SM and DR, see "Configuring PIM."

Configuration procedure

To configure a static group member:

N/A

The default setting is 2.

Step Command Remarks

1. Enter system view.

2. Enter interface view.

3. Configure the interface as a

static group member.

system-view interface

interface-number

igmp static-group

group-address [ source-address ]

interface-type

source

Configuring a multicast group policy

This feature enables an interface to filter IGMP reports by using an ACL that specifies multicast groups and the optional sources. It is used to control the multicast groups that the hosts attached to an interface can join.

To configure a multicast group policy:

Step Command Remarks

1. Enter system view.

system-view

N/A

By default, an interface is not a static group member of any multicast groups.

N/A

Step Command Remarks

2. Enter interface view.

3. Configure a multicast group

policy.

NOTE:

interface

interface-number

igmp group-policy

[ version-number ]

interface-type

acl-number

N/A

By default, an interface is not configured with a multicast group policy. Hosts attached to the interface can join any multicast groups.

This configuration cannot control a static group member.

Adjusting IGMP performance

Before adjusting IGMP performance, complete the following tasks:

• Configure any unicast routing protocol so that all devices can interoperate at the network layer.

• Configure basic IGMP features.

Configuring IGMP query and response parameters

The following are IGMP query and response parameters:

• IGMP querier's robustness variable—Number of times for retransmitting IGMP queries in

case of packet loss. A higher robustness variable makes the IGMP querier more robust, but it increases the timeout time for multicast groups.

• IGMP startup query interval—Interval at which an IGMP querier sends IGMP general queries

at startup.

• IGMP startup query count—Number of IGMP general queries that an IGMP querier sends at

startup.

• IGMP general query interval—Interval at which an IGMP querier sends IGMP general queries

to check for multicast group members on the network.

• IGMP last member query interval—In IGMPv2, it sets the interval at which a querier sends

group-specific queries after receiving a leave message. In IGMPv3, it sets the interval at which a querier sends group-and-source-specific queries after receiving a report that changes multicast source and group mappings.

• IGMP last member query count—In IGMPv2, it sets the number of group-specific queries that

a querier sends after receiving a leave message. In IGMPv3, it sets the number of group-and-source-specific queries that a querier sends after receiving a report that changes multicast source and group mappings.

• IGMP maximum response time—Maximum time before a receiver responds with a report to

an IGMP general query. This per-group timer is initialized to a random value in the range of 0 to the maximum response time specified in the IGMP query. When the timer value for a group decreases to 0, the receiver sends an IGMP report to the group.

• IGMP other querier present timer—Lifetime for an IGMP querier after a non-querier receives

an IGMP general query. If the non-querier does not receive a new query from the querier when this timer expires, the non-querier considers that the querier has failed and starts a new querier election.

Configuration restrictions and guidelines

When you configure the IGMP query and response parameters, follow these guidelines:

• You can configure the IGMP query and response parameters either for the current port in

interface view or globally for all ports in IGMP view. The configuration made in interface view takes priority over the configuration made in IGMP view.

• To avoid frequent IGMP querier changes, set the IGMP other querier present timer greater than

the IGMP general query interval. In addition, configure the same IGMP other querier present timer for all IGMP routers on the same subnet.

• To avoid mistakenly deleting multicast receivers, set the IGMP general query interval greater

than the maximum response time for IGMP general queries.

• To speed up the response to IGMP queries and avoid simultaneous timer expirations that cause

IGMP report traffic bursts, set an appropriate maximum response time.

{ For IGMP general queries, the maximum response time is set by the max-response-time

command.

{ For IGMP group-specific queries and IGMP group-and-source-specific queries, the

maximum response time equals the IGMP last member query interval.

• The following configurations take effect only on the devices that run IGMPv2 and IGMPv3:

{ Maximum response time for IGMP general queries.

{ IGMP last member query interval.

{ IGMP last member query count.

{ IGMP other querier present interval.

Configuring the IGMP query and response parameters globally

Step Command Remarks

1. Enter system view.

2. Enter IGMP view.

3. Set the IGMP querier's

robustness variable.

4. Set the IGMP startup query

interval.

5. Set the IGMP startup query

count.

6. Set the IGMP general query

interval.

7. Set the IGMP last member

query interval.

8. Set the IGMP last member

query count.

9. Set the maximum response

time for IGMP general queries.

system-view igmp

vpn-instance

[

vpn-instance-name ]

robust-count

startup-query-interval

startup-query-count

query-interval

last-member-query-interval

interval

last-member-query-count

max-response-time

count

interval

count

time

interval

count

N/A

By default, the IGMP querier's robustness variable is 2.

By default, the IGMP startup query interval equals one quarter of the IGMP general query interval.

By default, the IGMP startup query count equals the IGMP querier's robustness variable.

By default, the IGMP general query interval is 125 seconds.

By default, the IGMP last member query interval is 1 second.

By default, the IGMP last member query count equals the IGMP querier's robustness variable.

By default, the maximum response time for IGMP general queries is 10 seconds.

10. Set the IGMP other querier

present timer.

other-querier-present-interval

interval

By default, the IGMP other querier present timer is [ IGMP general query interval ] × [ IGMP robustness variable ] + [ maximum response time for IGMP general queries ] / 2.

Configuring the IGMP query and response parameters on an interface

Step Command Remarks

1. Enter system view.

system-view

N/A

2. Enter interface view.

3. Set the IGMP querier's

robustness variable.

4. Set the IGMP startup query

interval.

5. Set the IGMP startup query

count.

6. Set the IGMP general query

interval.

7. Set the IGMP last member

query interval.

8. Set the IGMP last member

query count.

9. Set the maximum response

time for IGMP general queries.

10. Set the IGMP other querier

present timer.

interface

interface-number

igmp robust-count

igmp startup-query-interval

interval

igmp startup-query-count

igmp query-interval

igmp last-member-query-interval

interval

igmp last-member-query-count

count

igmp max-response-time

igmp other-querier-present-interval

interval

interface-type

count

interval

count

time

N/A

By default, the IGMP querier's robustness variable is 2.

By default, the IGMP startup query interval equals one quarter of the IGMP general query interval.

By default, the IGMP startup query count equals the IGMP querier's robustness variable.

By default, the IGMP general query interval is 125 seconds.

By default, the IGMP last member query interval is 1 second.

By default, the IGMP last member query count equals the IGMP querier's robustness variable.

By default, the maximum response time for IGMP general queries is 10 seconds.

By default, the IGMP other querier present timer is [ IGMP general query interval ] × [ IGMP robustness variable ] + [ maximum response time for IGMP general queries ] / 2.

Enabling fast-leave processing

This feature enables an IGMP querier to send a leave notification directly to the upstream without sending group-specific queries or group-and-source-specific queries after receiving a leave message. This reduces leave latency and preserves the network bandwidth.

The fast-leave processing configuration takes effect only when the switch runs IGMPv2 or IGMPv3.

To enable fast-leave processing:

Step Command Remarks

1. Enter system view.

2. Enter interface view.

3. Enable fast-leave

processing.

system-view interface

interface-number

igmp fast-leave [ group-policy

acl-number ]

interface-type

N/A

By default, fast-leave processing is disabled.

Enabling IGMP NSR

This feature enables the switch to back up information about IGMP interfaces and IGMP forwarding entries to the standby process. After an active/standby switchover, the switch can recover the information without cooperation of other devices. This prevents the active/standby switchover from affecting the multicast service.

To enable IGMP NSR:

Step Command Remarks

1. Enter system view.

system-view

N/A

2. Enable IGMP NSR.

igmp non-stop-routing

Configuring IGMP SSM mappings

This feature enables the switch to provide SSM services for IGMPv1 or IGMPv2 hosts.

This feature does not process IGMPv3 messages. As a best practice, enable IGMPv3 on the receiver-side interface to ensure that IGMPv3 reports can be processed.

Configuration prerequisites

Before you configure IGMP SSM mappings, complete the following tasks:

• Configure any unicast routing protocol so that all devices in the domain can interoperate at the

network layer.

• Configure basic IGMP features.

Configuration procedure

To configure an IGMP SSM mapping:

By default, IGMP NSR is disabled.

Step Command Remarks

1. Enter system view.

2. Enter IGMP view.

3. Configure an IGMP

SSM mapping.

system-view igmp

[

vpn-instance-name ]

ssm-mapping

acl-number

N/A

vpn-instance

source-address

Displaying and maintaining IGMP

CAUTION:

The reset igmp group command might cause multicast data transmission failures.

Execute display commands in any view and reset commands in user view.

N/A

By default, IGMP SSM mappings are not configured.

Task Command

Display IGMP information about multicast groups.

Display IGMP information for interfaces.

Display IGMP SSM mappings.

Clear dynamic IGMP group entries.

display igmp [ vpn-instance

[ group-address |

static

[

display igmp[ vpn-instance

[ interface-type interface-number ] [

display igmp ssm-mapping

reset igmp interface

group-address [ [ source-address [

verbose

interface-type interface-number {

interface

]

vpn-instance

[

group-address

vpn-instance

[

mask

vpn-instance-name ]

interface-type interface-number ]

vpn-instance-name ]

{ mask | mask-length } ]

{ mask | mask-length } ] ] } }

IGMP configuration examples

Basic IGMP features configuration examples

Network requirements

As shown in Figure 32:

• OSPF and PIM-DM run on the network.

• VOD streams are sent to receiver hosts in multicast. Receiver hosts of different organizations

form stub networks N1 and N2. Host A and Host C are receiver hosts in N1 and N2, respectively.

• IGMPv2 runs between Switch A and N1, and between the other two switches and N2. Switch A

acts as the IGMP querier in N1. Switch B acts as the IGMP querier in N2 because it has a lower IP address.

group

interface

host

verbose

] [

all

]

group { all

Configure the routers to meet the following requirements:

• The hosts in N1 can join only multicast group 224.1.1.1.

• The hosts in N2 can join any multicast groups.

Figure 32 Network diagram

PIM-DM

Switch A

Querier

Switch B

Switch C

Configuration procedure

1. Assign an IP address and subnet mask to each interface according to Figure 32. (Details not

shown.)

2. Configure OSPF on the switches in the PIM-DM domain. (Details not shown.)

3. Enable IP multicast routing, IGMP, and PIM-DM:

# On Switch A, enable IP multicast routing.

<SwitchA> system-view [SwitchA] multicast routing [SwitchA-mrib] quit

# Enable IGMP on VLAN-interface 100.

[SwitchA] interface vlan-interface 100 [SwitchA-Vlan-interface100] igmp enable [SwitchA-Vlan-interface100] quit

# Enable PIM-DM on VLAN-interface 101.

[SwitchA] interface vlan-interface 101 [SwitchA-Vlan-interface101] pim dm [SwitchA-Vlan-interface101] quit

# On Switch B, enable IP multicast routing.

<SwitchB> system-view [SwitchB] multicast routing [SwitchB-mrib] quit

# Enable IGMP on VLAN-interface 200.

[SwitchB] interface vlan-interface 200 [SwitchB-Vlan-interface200] igmp enable [SwitchB-Vlan-interface200] quit

# Enable PIM-DM on VLAN-interface 201.

[SwitchB] interface vlan-interface 201 [SwitchB-Vlan-interface201] pim dm

Vlan-int100

10.110.1.1/24

Vlan-int200

10.110.2.1/24

Vlan-int200

10.110.2.2/24

Receiver

Host A

Host B

Receiver

Host C

Host D

[SwitchB-Vlan-interface201] quit

# On Switch C, enable IP multicast routing.

<SwitchC> system-view [SwitchC] multicast routing [SwitchC-mrib] quit

# Enable IGMP on VLAN-interface 200.

[SwitchC] interface vlan-interface 200 [SwitchC-Vlan-interface200] igmp enable [SwitchC-Vlan-interface200] quit

# Enable PIM-DM on VLAN-interface 202.

[SwitchC] interface vlan-interface 202 [SwitchC-Vlan-interface202] pim dm [SwitchC-Vlan-interface202] quit

4. Configure a multicast group policy on Switch A so that the hosts connected to VLAN-interface

100 can join only multicast group 224.1.1.1.

[SwitchA] acl number 2001 [SwitchA-acl-basic-2001] rule permit source 224.1.1.1 0 [SwitchA-acl-basic-2001] quit [SwitchA] interface vlan-interface 100 [SwitchA-Vlan-interface100] igmp group-policy 2001 [SwitchA-Vlan-interface100] quit

Verifying the configuration

# Display IGMP information on VLAN-interface 200 of Switch B.

[SwitchB] display igmp interface vlan-interface 200 Vlan-interface200(10.110.2.1): IGMP is enabled. IGMP version: 2 Query interval for IGMP: 125s Other querier present time for IGMP: 255s Maximum query response time for IGMP: 10s Querier for IGMP: 10.110.2.1 (This router) IGMP groups reported in total: 1

IGMP SSM mapping configuration example

Network requirements

As shown in Figure 33:

• OSPF runs on the network.

• The PIM-SM domain uses both the ASM model and SSM model for multicast delivery.

VLAN-interface 104 on Switch D acts as the C-BSR and C-RP. The SSM group range is

232.1.1.0/24.

• IGMPv3 runs on VLAN-interface 400 of Switch D. The receiver host runs IGMPv2, and does not

support IGMPv3. Therefore, the receiver host cannot specify expected multicast sources in its membership reports.

• Source 1, Source 2, and Source 3 send multicast packets to multicast groups in the SSM group

range.

Configure the IGMP SSM mapping feature on Switch D so that the receiver host can receive multicast data from Source 1 and Source 3 only.

Figure 33 Network diagram

Source 2

Source 1

Switch B Switch C

Vlan-int200 Vlan-int300

Vlan-int100

Switch A

Vlan-int102

Vlan-int101

Vlan-int104

Vlan-int102

Vlan-int103

PIM-SM

Vlan-int103

Vlan-int400

Vlan-int104

Switch D

Source 3

Receiver

Table 6 Interface and IP address assignment

Device Interface IP address Device Interface IP address

Source 1 — 133.133.1.1/24 Source 3 — 133.133.3.1/24

Source 2 — 133.133.2.1/24 Receiver — 133.133.4.1/24

Switch A Vlan-int100 133.133.1.2/24 Switch C Vlan-int300 133.133.3.2/24

Switch A Vlan-int101 192.168.1.1/24 Switch C

Switch A Vlan-int104 192.168.4.2/24 Switch C

Vlan-int103 192.168.3.1/24

Vlan-int102 192.168.2.2/24

Switch B Vlan-int200 133.133.2.2/24 Switch D Vlan-int400 133.133.4.2/24

Switch B Vlan-int101 192.168.1.2/24 Switch D

Switch B Vlan-int102 192.168.2.1/24 Switch D

Configuration procedure

1. Assign an IP address and subnet mask to each interface according to Table 6. (Details not

shown.)

2. Configure OSPF on the switches in the PIM-SM domain. (Details not shown.)

3. Enable IP multicast routing, PIM-SM, and IGMP:

# On Switch D, enable IP multicast routing.

<SwitchD> system-view [SwitchD] multicast routing [SwitchD-mrib] quit

# Enable IGMPv3 on the receiver-side interface (VLAN-interface 400).

[SwitchD] interface vlan-interface 400 [SwitchD-Vlan-interface400] igmp enable [SwitchD-Vlan-interface400] igmp version 3 [SwitchD-Vlan-interface400] quit

# Enable PIM-SM on the other interfaces.

[SwitchD] interface vlan-interface 103 [SwitchD-Vlan-interface103] pim sm [SwitchD-Vlan-interface103] quit

Vlan-int103 192.168.3.2/24

Vlan-int104 192.168.4.1/24

[SwitchD] interface vlan-interface 104 [SwitchD-Vlan-interface104] pim sm [SwitchD-Vlan-interface104] quit

# On Switch A, enable IP multicast routing, and enable PIM-SM on each interface.

<SwitchA> system-view [SwitchA] multicast routing [SwitchA-mrib] quit [SwitchA] interface vlan-interface 100 [SwitchA-Vlan-interface100] pim sm [SwitchA-Vlan-interface100] quit [SwitchA] interface vlan-interface 101 [SwitchA-Vlan-interface101] pim sm [SwitchA-Vlan-interface101] quit [SwitchA] interface vlan-interface 104 [SwitchA-Vlan-interface104] pim sm [SwitchA-Vlan-interface104] quit

# Configure Switch B and Switch C in the same way Switch A is configured. (Details not shown.)

4. Configure a C-BSR and a C-RP on Switch D.

[SwitchD] pim [SwitchD-pim] c-bsr 192.168.4.1 [SwitchD-pim] c-rp 192.168.4.1 [SwitchD-pim] quit

5. Configure the SSM group range:

# Configure the SSM group range as 232.1.1.0/24 on Switch D.

[SwitchD] acl number 2000 [SwitchD-acl-basic-2000] rule permit source 232.1.1.0 0.0.0.255 [SwitchD-acl-basic-2000] quit [SwitchD] pim [SwitchD-pim] ssm-policy 2000 [SwitchD-pim] quit

# Configure the SSM group range on Switch A, Switch B, and Switch C in the same way Switch D is configured. (Details not shown.)

6. Configure IGMP SSM mappings on Switch D.

[SwitchD] igmp [SwitchD-igmp] ssm-mapping 133.133.1.1 2000 [SwitchD-igmp] ssm-mapping 133.133.3.1 2000 [SwitchD-igmp] quit

Verifying the configuration

# Display IGMP SSM mappings for multicast group 232.1.1.1 on Switch D.

[SwitchD] display igmp ssm-mapping 232.1.1.1 Group: 232.1.1.1 Source list:

133.133.1.1

133.133.3.1

# Display information about IGMP multicast groups that hosts have dynamically joined on Switch D.

[SwitchD] display igmp group IGMP groups in total: 1

HP FlexNetwork 7500 Configuration Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents

Multicast overview

Introduction to multicast

Information transmission techniques

Broadcast

Multicast

Multicast features

Common notations in multicast

Multicast benefits and applications

Multicast benefits

Multicast applications

Multicast models

ASM model

SFM model

SSM model

Multicast architecture

Multicast addresses

IP multicast addresses

Ethernet multicast MAC addresses

Multicast protocols

Layer 3 multicast protocols

Layer 2 multicast protocols

Multicast packet forwarding mechanism

Configuring IGMP snooping

Overview

IGMP snooping ports

Router ports

Member ports

How IGMP snooping works

General query

IGMP report

Leave message

Protocols and standards

General configuration restrictions and guidelines

IGMP snooping configuration task list

Configuring basic IGMP snooping features

Enabling IGMP snooping

Enabling IGMP snooping for the specified VLANs

Enabling IGMP snooping for a VLAN

Specifying an IGMP snooping version

Specifying an IGMP snooping version for the specified VLANs

Specifying an IGMP snooping version for a VLAN

Setting the maximum number of IGMP snooping forwarding entries

Setting the IGMP last member query interval

Configuration restrictions and guidelines

Setting the IGMP last member query interval globally

Setting the IGMP last member query interval in a VLAN

Configuring IGMP snooping port features

Setting aging timers for dynamic ports

Setting the aging timers for dynamic ports globally

Setting the aging timers for dynamic ports in a VLAN

Configuring static ports

Configuring a port as a simulated member host

Enabling fast-leave processing

Configuration restrictions and guidelines

Enabling fast-leave processing globally

Enabling fast-leave processing on a port

Disabling a port from becoming a dynamic router port

Configuring the IGMP snooping querier

Configuration prerequisites

Enabling the IGMP snooping querier

Configuring parameters for IGMP general queries and responses

Configuration restrictions and guidelines

Configuring the parameters for IGMP general queries and responses globally

Configuring parameters for IGMP general queries and responses in a VLAN

Configuring parameters for IGMP messages

Configuration prerequisites

Configuring source IP addresses for IGMP messages

Setting the 802.1p priority for IGMP messages

Setting the 802.1p priority for IGMP messages globally

Setting the 802.1p priority for IGMP messages in a VLAN

Configuring IGMP snooping policies

Configuring a multicast group policy

Configuration restrictions and guidelines

Configuring a multicast group policy globally

Configuring a multicast group policy on a port