HP A5120 EI Configuration Manual

HP A5120 EI Switch Series

Part number: 5998-1791 Software version: Release 2208

Document version: 5W100-20110530

Layer 2 - LAN Switching Configuration Guide

Abstract

This document describes the software features for the HP A Series products and guides you through the software configuration procedures. These configuration guides also provide configuration examples to help you apply software features to different network scenarios.

This documentation is intended for network planners, field technical support and servicing engineers, and network administrators working with the HP A Series products.

Legal and notice information

No part of this documentation may be reproduced or transmitted in any form or by any means without prior written consent of Hewlett-Packard Development Company, L.P.

The information contained herein is subject to change without notice.

HEWLETT-PACKARD COMPANY MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Hewlett-Packard shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material.

The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

Contents

Ethernet interface configuration ····································································································································· 1

Ethernet interface naming conventions ··························································································································· 1 Configuring basic settings of an Ethernet interface ······································································································· 1

Configuring a combo interface ······························································································································· 1 Configuring basic settings of an Ethernet interface ······························································································ 2 Setting speed options for auto negotiation on an Ethernet interface ·································································· 3 Configuring generic flow control on an Ethernet interface ·················································································· 4 Configuring link change suppression on an Ethernet interface ··········································································· 5 Configuring loopback testing on an Ethernet interface ························································································ 6 Configuring a port group ········································································································································ 7 Configuring traffic storm protection························································································································ 7 Setting the statistics polling interval ························································································································ 9 Enabling the auto power-down function on an Ethernet interface ··································································· 10 Configuring jumbo frame support ······················································································································· 10 Enabling single-port loopback detection on an Ethernet interface··································································· 11 Enabling multi-port loopback detection··············································································································· 12 Setting the MDI mode of an Ethernet interface ·································································································· 13 Enabling bridging on an Ethernet interface ······································································································· 14 Testing the cable connection of an Ethernet interface ······················································································· 14

Displaying and maintaining an Ethernet interface ····································································································· 15

Loopback and null interface configuration ················································································································· 17

Loopback interface ························································································································································· 17

Introduction to loopback interface ······················································································································· 17 Configuring a loopback interface ······················································································································· 17

Null interface ·································································································································································· 18

Introduction to null interface ································································································································· 18 Configuring null 0 interface ································································································································· 18

Displaying and maintaining loopback and null interfaces ························································································ 18

MAC address table configuration ································································································································ 20

How a MAC address table entry is created ······································································································· 20 Types of MAC address table entries ··················································································································· 20 MAC address table-based frame forwarding ···································································································· 21

Configuring the MAC address table ···························································································································· 21

Manually configuring MAC address table entries ····························································································· 21 Disabling MAC address learning ························································································································ 22 Configuring the aging timer for dynamic MAC address entries ······································································ 23

Configuring the MAC learning limit on ports ····································································································· 24 Displaying and maintaining MAC address tables ····································································································· 24 MAC address table configuration example ················································································································ 25

MAC Information configuration ··································································································································· 26

Introduction to MAC Information ························································································································· 26

How MAC Information works ······························································································································ 26 Configuring MAC Information ······································································································································ 26

Enabling MAC Information globally ··················································································································· 26

Enabling MAC Information on an interface ······································································································· 26

Configuring MAC Information mode ·················································································································· 27

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Configuring the interval for sending Syslog or trap messages········································································· 27

Configuring the MAC Information queue length································································································ 27 MAC Information configuration example ···················································································································· 28

Ethernet link aggregation configuration ······················································································································ 29

Basic concepts ······················································································································································· 29

Aggregating links in static mode ························································································································· 32

Aggregating links in dynamic mode ··················································································································· 34

Load-sharing criteria for link aggregation groups ····························································································· 36 Ethernet link aggregation configuration task list ········································································································· 36 Configuring an aggregation group ····························································································································· 36

Configuration guidelines ······································································································································ 36

Configuring a static aggregation group ············································································································· 37

Configuring a dynamic aggregation group ······································································································· 37 Configuring an aggregate interface ···························································································································· 38

Configuring the description of an aggregate interface····················································································· 39

Enabling link state traps for an aggregate interface ························································································· 39

Shutting down an aggregate interface ··············································································································· 39 Configuring load sharing for link aggregation groups ······························································································ 40

Configuring load-sharing criteria for link aggregation groups ········································································ 40

Enabling local-first load sharing for link aggregation ······················································································· 41 Enabling link-aggregation traffic redirection··············································································································· 42 Displaying and maintaining Ethernet link aggregation ····························································································· 43 Ethernet link aggregation configuration examples ····································································································· 43

Layer 2 static aggregation configuration example ···························································································· 44

Layer 2 dynamic aggregation configuration example ······················································································ 46

Layer 2 aggregation load sharing configuration example ··············································································· 48

Port isolation configuration ··········································································································································· 51

Introduction to port isolation ········································································································································· 51 Configuring the isolation group ··································································································································· 51 Displaying and maintaining isolation groups ············································································································· 52 Port isolation configuration example ··························································································································· 52

MSTP configuration ······················································································································································· 54

Introduction to STP ························································································································································· 54

Why STP ································································································································································· 54

Protocol packets of STP ········································································································································· 54

Basic concepts in STP ··········································································································································· 55

How STP works ······················································································································································ 56 Introduction to RSTP ······················································································································································· 62 Introduction to MSTP ······················································································································································ 62

Why MSTP ····························································································································································· 62

Basic concepts in MSTP ········································································································································ 63

How MSTP works ·················································································································································· 66

Implementation of MSTP on devices···················································································································· 67

Configuring an MST region ································································································································· 69

Configuring the root bridge or a secondary root bridge ·················································································· 69

Configuring the work mode of an MSTP device ································································································ 70

Configuring the priority of a device ···················································································································· 71

Configuring the maximum hops of an MST region ··························································································· 71

Configuring the network diameter of a switched network ················································································ 72

Configuring timers of MSTP ································································································································· 72

Configuring the timeout factor ····························································································································· 73

Configuring the maximum port rate ···················································································································· 74

Configuring ports as edge ports ·························································································································· 74

Configuring path costs of ports ···························································································································· 75

Configuring port priority ······································································································································· 77

Configuring the link type of ports ························································································································ 78

Configuring the mode a port uses to recognize/send MSTP packets ····························································· 79

Enabling the output of port state transition information ···················································································· 80

Enabling the MSTP feature ··································································································································· 80

Performing mCheck ··············································································································································· 80

Configuring Digest Snooping ······························································································································ 81

Configuring No Agreement Check ····················································································································· 83

Configuring protection functions ·························································································································· 85 Displaying and maintaining MSTP ······························································································································· 88 MSTP configuration example ········································································································································ 89

BPDU tunneling configuration ······································································································································· 94

Introduction to BPDU tunneling ····································································································································· 94

Background ···························································································································································· 94

BPDU tunneling implementation ··························································································································· 95 Configuring BPDU tunneling ········································································································································· 96

Configuration prerequisites ·································································································································· 96

Enabling BPDU tunneling ······································································································································ 97

Configuring destination multicast MAC address for BPDUs ············································································· 97 BPDU tunneling configuration examples······················································································································ 98

BPDU tunneling for STP configuration example ································································································· 98

BPDU tunneling for PVST configuration example ······························································································· 99

VLAN configuration ···················································································································································· 101

Introduction to VLAN ··················································································································································· 101

VLAN overview ···················································································································································· 101

VLAN fundamentals ············································································································································ 101

Types of VLANs ··················································································································································· 102 Configuring basic VLAN settings ······························································································································· 103 Configuring basic settings of a VLAN interface ······································································································· 104 Port-based VLAN configuration ·································································································································· 104

Introduction to port-based VLAN ······················································································································· 104

Assigning an access port to a VLAN ················································································································ 106

Assigning a trunk port to a VLAN ····················································································································· 107

Assigning a hybrid port to a VLAN ··················································································································· 108

Port-based VLAN configuration example ·········································································································· 109 MAC-based VLAN configuration ································································································································ 110

Introduction to MAC-based VLAN ····················································································································· 110

Configuring MAC-based VLAN ························································································································· 112

MAC-based VLAN configuration example ······································································································· 115 Protocol-based VLAN configuration ··························································································································· 118

Introduction to protocol-based VLAN ················································································································ 118

Configuring a protocol-based VLAN ················································································································· 118

Protocol-based VLAN configuration example ·································································································· 120 IP Subnet-based VLAN configuration ························································································································· 122

Introduction ·························································································································································· 122

Configuring an IP subnet-based VLAN ············································································································· 122 Displaying and maintaining VLAN ···························································································································· 124

Isolate-user-VLAN configuration ································································································································ 125

Overview······································································································································································· 125 Configuring isolate-user-VLAN ···································································································································· 125

Configuring an isolate-user-VLAN ····················································································································· 126

Configuring secondary VLANs ·························································································································· 127

Associating secondary VLANs with an isolate-user-VLAN ·············································································· 128 Displaying and maintaining isolate-user-VLAN ········································································································· 128 Isolate-user-VLAN configuration example ·················································································································· 129

Voice VLAN configuration ········································································································································· 132

OUI addresses ····················································································································································· 132

Voice VLAN assignment modes ························································································································· 132

Security mode and normal mode of voice VLANs ··························································································· 135 Configuring a voice VLAN ·········································································································································· 136

Configuring QoS priority settings for voice traffic on an interface ································································ 136

Configuring a port to operate in automatic voice VLAN assignment mode ················································· 137

Configuring a port to operate in manual voice VLAN assignment mode ····················································· 138 Displaying and maintaining voice VLAN ·················································································································· 139 Voice VLAN configuration examples ························································································································· 139

Automatic voice VLAN mode configuration example ····················································································· 139

Manual voice VLAN assignment mode configuration example ····································································· 141

GVRP configuration ···················································································································································· 143

Introduction to GVRP ···················································································································································· 143

GARP ···································································································································································· 143

GVRP ···································································································································································· 146

Protocols and standards ····································································································································· 147 GVRP configuration task list ········································································································································ 147 Configuring GVRP functions ······································································································································· 147 Configuring GARP timers ············································································································································ 148 Displaying and maintaining GVRP····························································································································· 149 GVRP configuration examples ···································································································································· 150

GVRP normal registration mode configuration example ················································································· 150

GVRP fixed registration mode configuration example ···················································································· 151

GVRP forbidden registration mode configuration example ············································································ 152

QinQ configuration ···················································································································································· 155

Introduction to QinQ ··················································································································································· 155

Background and benefits ···································································································································· 155

How QinQ works ················································································································································ 155

QinQ frame structure ·········································································································································· 156

Implementations of QinQ ··································································································································· 157

Modifying the TPID in a VLAN tag ···················································································································· 157

Enabling basic QinQ ·········································································································································· 159

Configuring VLAN transparent transmission ···································································································· 159 Configuring selective QinQ ········································································································································ 160

Configuring an outer VLAN tagging policy ····································································································· 160

Configuring an inner-outer VLAN 802.1p priority mapping·········································································· 161 Configuring the TPID value in VLAN tags ················································································································· 162 QinQ configuration examples ···································································································································· 162

Basic QinQ configuration example··················································································································· 162

Selective QinQ Configuration Example ············································································································ 164

LLDP configuration ······················································································································································ 168

How LLDP works ·················································································································································· 172

Enabling LLDP ······················································································································································ 174

Setting the LLDP operating mode ······················································································································· 174

Setting the LLDP re-initialization delay ·············································································································· 175

Enabling LLDP polling ········································································································································· 175

Configuring the advertisable TLVs ····················································································································· 175

Configuring the management address and its encoding format ···································································· 176

Setting other LLDP parameters ···························································································································· 177

Setting an encapsulation format for LLDPDUs ·································································································· 177 Configuring CDP compatibility ··································································································································· 178

Configuring CDP compatibility ·························································································································· 178 Configuring LLDP trapping ·········································································································································· 179 Displaying and maintaining LLDP ······························································································································· 180 LLDP configuration examples ······································································································································ 180

Basic LLDP configuration example ····················································································································· 180

CDP-compatible LLDP configuration example ··································································································· 183

Support and other resources ····································································································································· 185

Contacting HP ······························································································································································ 185

Subscription service ············································································································································ 185 Related information ······················································································································································ 185

Documents ···························································································································································· 185

Websites ······························································································································································ 185 Conventions ·································································································································································· 186

Index ············································································································································································· 188

vii

Ethernet interface configuration

NOTE:

 For more information about the expansion cards, see the

HP A5120 EI Switch Series Installation Guide.

 The HP A5120-24G EI Switch(JE066A) and the HP A5120-48G EI Switch(JE067A) do not support IRF.

Ethernet interface naming conventions

The GE and 10-GE interfaces on the A5120 EI Switch Series are named in the format of interface-type A/B/C, where the following definitions apply:

 If the switch does not support Intelligent Resilient Framework (IRF), A takes 1. If the switch supports

IRF, A represents the ID of the switch in an IRF fabric. If the switch is not assigned to any IRF fabric, A uses 1.

 B represents a slot number on the switch. It uses 0 for fixed interfaces, 1 for interfaces on interface

expansion card 1, and 2 for interfaces on interface expansion card 2.

 C represents the number of an interface on a slot.

Configuring basic settings of an Ethernet interface

Configuring a combo interface

Introduction to combo interfaces

A combo interface is a logical interface that comprises one optical (fiber) port and one electrical (copper) port. The two ports share one forwarding interface, so they cannot work simultaneously. When you enable one port, the other is automatically disabled.

The fiber combo port and the copper combo port are Layer 2 Ethernet interfaces. They have their own separate interface views, in which you can activate the fiber or copper combo port and configure other port attributes such as the interface rate and duplex mode.

Configuration prerequisites

Before you configure a combo interface, complete the following tasks:

 Use the display port combo command to identify the combo interfaces on your device and identify

the two physical ports that compose each combo interface.

 Use the display interface command to determine, of the two physical ports that compose a combo

interface, which is the fiber combo port and which is the cooper combo port. If the current port is the copper port, the output will include ―Media type is twisted pair, Port hardware type is 1000_BASE_T‖. If the current port is the fiber port, the output will include ―Media type is not sure, Port hardware type is No connector‖.

Changing the active port of a combo interface

Follow these steps to change the active port of a double combo interface:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Activate the current interface

undo shutdown

Optional

By default, of the two ports that compose a combo interface, the one with a smaller port ID is active.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Change the description of the interface

description text

Optional

By default, the description of an interface is the interface name followed by the ―Interface‖ string, GigabitEthernet1/0/1 Interface for example.

Set the duplex mode

duplex { auto | full | half }

Optional

The optical port of an SFP port and the electrical port of an Ethernet port whose port rate is configured as 1000 Mbps do not support the half keyword.

The default duplex mode of a port is auto negotiation.

Configuring basic settings of an Ethernet interface

You can set an Ethernet interface to operate in one of the following duplex modes:

 Full-duplex mode (full): Interfaces that operates in this mode can send and receive packets

simultaneously.

 Half-duplex mode (half): Interfaces that operates in this mode cannot send and receive packets

simultaneously.

 Auto-negotiation mode (auto): Interfaces that operates in this mode negotiate a duplex mode with

their peers.

You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its peer. For a 100-Mbps or 1000-Mbps Layer 2 Ethernet interface, you can also set speed options for auto negotiation. The two ends can select a speed only from the available options. For more information, see ―Setting speed options for auto negotiation on an Ethernet interface.‖

Follow these steps to configure an Ethernet interface:

To do…

Use the command…

Remarks

Set the interface speed

speed { 10 | 100 | 1000 | auto }

Optional

The optical port of an SFP port does not support the 10 and 100 keywords.

By default, the auto option is enabled.

Shut down the Ethernet interface

shutdown

Optional

By default, an Ethernet interface is in the up state.

To bring up an Ethernet interface, use the undo shutdown command.

NOTE:

Optical interfaces do not support this feature.

IP network

Server 1 Server 3Server 2

( Speed 1000 Mbps )

GE1/0/1

GE1/0/2

GE1/0/3

GE1/0/4

( Speed 1000 Mbps )

Setting speed options for auto negotiation on an Ethernet interface

As shown in Figure 1, speed auto negotiation enables an Ethernet interface to negotiate with its peer for the highest speed that both ends support by default. You can narrow down the speed option list for negotiation.

Figure 1 Speed auto negotiation application scenario

All interfaces on the switch are operating in speed auto negotiation mode, with the highest speed of 1000 Mbps. If the transmission rate of each server in the server cluster is 1000 Mbps, their total transmission rate will exceed the capability of interface GigabitEthernet 1/0/4, the interface providing access to the Internet for the servers.

To avoid congestion on GigabitEthernet 1/0/4, set 100 Mbps as the only speed option available for negotiation on interface GigabitEthernet 1/0/1, GigabitEthernet 1/0/2, and GigabitEthernet 1/0/3. As a result, the transmission rate on each interface connected to a server is limited to 100 Mbps.

Follow these steps to configure an auto-negotiation transmission rate:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Set speed options for auto negotiation

speed auto [ 10 | 100 | 1000 ] *

Optional

NOTE:

 This function is only available for Gigabit Layer-2 copper (electrical) Ethernet interfaces that support speed auto

negotiation.

 The speed and speed auto commands supersede each other, and whichever is configured last takes effect.

Port A

Switch A Switch B

Port B

1000Mbps

Port C 100Mbps

1000Mbps

Port D

100Mbps

Switch C

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

— Enable TxRx mode flow control

flow-control

Required

Use either command.

By default, flow control is disabled on an Ethernet interface.

Enable Rx mode flow control

flow-control receive enable

Configuring generic flow control on an Ethernet interface

An interface implements generic flow control by sending and receiving common pause frames. The following generic flow control modes are available:

 TxRx mode enables an interface to both send and receive common pause frames.  Rx mode enables an interface to receive but not send common pause frames.

In Figure 2, when both Port A and Port B forward packets at 1000 Mbps, Port C is congested. To avoid packet loss, enable flow control on Port A and Port B.

Figure 2 Flow control application scenario

Configure Port B to operate in TxRx mode, Port A in Rx mode.

 When congestion occurs on Port C, Switch B buffers frames. When the amount of buffered frames

exceeds a certain value, Switch B sends a common pause frame out of Port B to ask Port A to suspend sending packets. This pause frame also tells Port A for how long it is expected to pause.

 Upon receiving the common pause frame from Port B, Port A suspends sending packets to Port B for

a period.

 If congestion persists, Port B keeps sending common pause frames to Port A until the congestion

condition is removed.

Follow these steps to configure flow control on an interface:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interface-number

—

Set a link-down suppression interval

link-delay delay-time

Required

Link-down suppression is disabled by default.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Set a link-up suppression interval

link-delay delay-time mode up

Required

Link-up suppression is disabled by default.

Configuring link change suppression on an Ethernet interface

An Ethernet interface has two physical link states: up and down. Each time the physical link of an interface goes up or comes down, the physical layer reports the change to the upper layers, and the upper layers handle the change, resulting in increased overhead.

To prevent physical link flapping from affecting system performance, configure link change suppression to delay the reporting of physical link state changes. When the delay expires, the interface reports any detected change.

Link change suppression does not suppress administrative up or down events. When you shut down or bring up an interface by using the shutdown or undo shutdown command, the interface reports the event to the upper layers immediately.

On an A5120 EI switch, you can configure link-down suppression or link-up suppression, but not both.

Link-down suppression enables an interface to suppress link-down events and start a delay timer each time the physical link goes down. During this delay, the interface does not report the link-down event, and the display interface brief or display interface command displays the interface state as UP. If the physical link is still down when the timer expires, the interface reports the link-down event to the upper layers.

Link-up suppression enables an interface to suppress link-up events and start a delay timer each time the physical link goes up. During this delay, the interface does not report the link-up event, and the display interface brief or display interface command displays the interface state as DOWN. If the physical link is still up when the timer expires, the interface reports the link-up event to the upper layers.

Configuring link-down suppression

Follow these steps to enable an Ethernet interface to suppress link-down events:

Configuring link-up suppression

Follow these steps to configure link-up suppression on an Ethernet interface:

NOTE:

The link-delay mode up command and the link-delay command supersedes each other, and whichever is configured last takes effect.

Port 1 Port 2

Switching chip

Switch

Test packets Looped packets

Port 1

Port 2

Switching chip

Switch

Loopback

plug

Test packets Looped packets

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

— Perform loopback testing

loopback { external | internal }

Required

Configuring loopback testing on an Ethernet interface

You can perform loopback testing on an Ethernet interface to determine whether the interface functions properly. The Ethernet interface cannot forward data packets during the testing. Loopback testing falls into the following categories:

 Internal loopback testing, which tests all on-chip functions related to Ethernet interfaces. As shown in

Figure 3, internal loopback testing is performed on Port 1. During internal loopback testing, the

interface sends a certain number of test packets, which are looped back to the interface over the self-loop created on the switching chip.

Figure 3 Internal loopback testing

 External loopback testing, which tests the hardware of Ethernet interfaces. As shown in Figure 4,

external loopback testing is performed on Port 1. To perform external loopback testing on an Ethernet interface, insert a loopback plug into the interface. During external loopback testing, the interface sends a certain number of test packets, which are looped over the plug and back to the interface. If the interface fails to receive any test packet, the hardware of the interface is faulty.

Figure 4 External loopback testing

Follow these steps to perform loopback testing on an Ethernet interface:

NOTE:

 On an interface that is physically down, you can only perform internal loopback testing. On an interface

administratively shut down, you can perform neither internal nor external loopback testing.

 The speed, duplex, mdi, and shutdown commands are not available during loopback testing.  During loopback testing, the Ethernet interface operates in full duplex mode. When you disable loopback testing,

the port returns to its duplex setting.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Create a port group and enter port group view

port-group manual port-groupname

Required

Assign Ethernet interfaces to the port group

group-member interface-list

Required

Shut down all Ethernet interfaces in the port group

shutdown

Optional

By default, all Ethernet interfaces in a port group are up. To bring up all Ethernet interfaces shut down manually in a port group, use the undo shutdown command in port group view.

Configuring a port group

Some interfaces on your switch might use the same set of settings. To configure these interfaces in bulk rather than one by one, you can assign them to a port group.

You create port groups manually. All settings made for a port group apply to all the member ports of the group. For example, you can configure a traffic suppression threshold (see ―Configuring traffic storm

protection‖) for multiple interfaces in bulk by assigning these interfaces to a port group.

Even though the settings are made on the port group, they are saved on each interface basis rather than on a port group basis. You can only view the settings in the view of each interface by using the display current-configuration or display this command.

Follow these steps to configure a port group:

Configuring traffic storm protection

A traffic storm occurs when a large amount of broadcast, multicast, or unknown unicast packets congest a network. The A5120 EI switches provide the following storm protection approaches:

 Storm suppression, which you can use to limit the size of monitored traffic that passes through an

Ethernet interface by setting a traffic threshold. The port discards all traffic that exceeds the threshold.

 Storm control, which you can use to shut down Ethernet interfaces or block traffic when monitored

traffic exceeds the traffic threshold. Depending on your configuration, storm control can also enable an interface to send trap or log messages when monitored traffic reaches a certain traffic threshold.

For a particular type of traffic, configure either storm suppression or storm control, but not both. If you configure both of them, you might fail to achieve the expected storm control effect.

Configuring storm suppression on an Ethernet interface

NOTE:

If one suppression threshold has been set in pps on an Ethernet interface, you must set other suppression thresholds in pps. If one suppression threshold has been set in percentage or kbps, you cannot set other suppression thresholds in pps.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view or port group view

Enter Ethernet interface view

interface interface-type interfacenumber

Use either command.

To configure storm suppression on one Ethernet interface, enter Ethernet interface view.

To configure storm suppression on a group of Ethernet interfaces, enter port group view.

Enter port group view

port-group manual port-group-name Set a broadcast suppression

threshold

broadcast-suppression { ratio | pps max-pps | kbps max-bps }

Optional

By default, all broadcast traffic is allowed to pass through an interface.

Set a multicast suppression threshold

multicast-suppression { ratio | pps max-pps | kbps max-bps }

Optional

By default, all multicast traffic is allowed to pass through an interface.

Set a unknown unicast suppression threshold

unicast-suppression { ratio | pps maxpps | kbps max-bps }

Optional

By default, all unknown unicast traffic is allowed to pass through an interface.

NOTE:

If you set a storm suppression threshold in both Ethernet interface view and port group view, the threshold configured last takes effect.

You can use the following guidelines to set one suppression threshold for broadcast, multicast, and unknown unicast traffic separately on an Ethernet interface.

 Set the threshold as a percentage of the interface transmission capability.  Set the threshold in kbps, limiting the number of kilobits of monitored traffic passing through the

interface per second.

 Set the threshold in pps, limiting the number of monitored packets passing through the interface per

second.

Follow these steps to configure storm suppression on an Ethernet interface:

Configuring storm control on an Ethernet interface

Storm control compares broadcast, multicast, and unknown unicast traffic regularly with their respective traffic thresholds on an Ethernet interface. For each type of traffic, storm control provides a lower threshold and a higher threshold.

For management purposes, you can configure the interface to send threshold event traps and log

To do…

Use the command…

Remarks

Enter system view

system-view

—

Set the traffic polling interval of the storm control module

storm-constrain interval seconds

Optional

10 seconds by default.

Enter Ethernet interface view

interface interface-type interfacenumber

—

Enable storm control, and set the lower and upper thresholds for broadcast, multicast, or unknown unicast traffic

storm-constrain { broadcast | multicast | unicast } { pps | kbps | ratio } max-pps-values min-pps- values

Required

Disabled by default.

Set the control action to take when monitored traffic exceeds the upper threshold

storm-constrain control { block | shutdown }

Optional

Disabled by default.

Enable the interface to send storm control threshold event traps.

storm-constrain enable trap

Optional

By default, the interface sends traps when monitored traffic exceeds the upper threshold or drops below the lower threshold from the upper threshold.

Enable the interface to log storm control threshold events.

storm-constrain enable log

Optional

By default, the interface outputs log messages when monitored traffic exceeds the upper threshold or falls below the lower threshold from the upper threshold.

NOTE:

 For network stability, use the default or set a higher traffic polling interval.  Storm control uses a complete polling cycle to collect traffic data, and analyzes the data in the next cycle. An

interface takes one to two polling intervals to take a storm control action.

messages when monitored traffic exceeds the upper threshold or falls below the lower threshold from the upper threshold.

When the traffic exceeds its higher threshold, the interface does either of the following, depending on your configuration:

 Blocks the particular type of traffic, while forwarding other types of traffic. Even though the interface

does not forward the blocked traffic, it still counts the traffic. When the blocked traffic drops below the threshold, the interface begins to forward the traffic.

 Shuts down automatically. The interface shuts down automatically and stops forwarding any traffic.

To bring up the interface, use the undo shutdown command or disable the storm control function.

Follow these steps to configure the storm control function on an Ethernet interface:

Setting the statistics polling interval

Follow these steps to set the statistics polling interval on an Ethernet interface:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Set the statistics polling interval on the Ethernet interface

flow-interval interval

Optional

The default interface statistics polling interval is 300 seconds.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view or port group view

Enter Ethernet interface view

interface interface-type interfacenumber

Use either command.

To configure auto power-down on one Ethernet interface, enter Ethernet interface view.

To configure auto power-down on a group of Ethernet interfaces, enter port group view.

Enter port group view

port-group manual port-group-name Enable auto power-down on an

Ethernet interface

port auto-power-down

Required

Disabled by default.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interface-number

Use either command.

To display the interface statistics collected in the last polling interval, use the display interface command.

To clear interface statistics, use the reset counters interface command.

Enabling the auto power-down function on an Ethernet interface

To save power, enable the auto power-down function on Ethernet interfaces. An interface enters the power save mode if it has not received any packet for a certain period of time (this interval depends on the specifications of the chip, and is not configurable). When a packet arrives later, the interface enters its normal state.

Follow these steps to enable auto power-down on an Ethernet interface:

Configuring jumbo frame support

Ethernet frames longer than the standard Ethernet frame size (1536 bytes) are called "jumbo frames", which are typical of file transfer.

 If you set an Ethernet interface to accept jumbo frames, it allows frames up to 9216 bytes to pass

through.

 If you disable an Ethernet interface to accept jumbo frames, it allows frames up to 1536 bytes to

pass through.

Follow these steps to configure jumbo frame support in Ethernet interface view:

To do…

Use the command…

Remarks

or port group view

Enter port group view

To configure jumbo frame support on one Ethernet interface, enter Ethernet interface view.

To configure jumbo frame support on a group of Ethernet interfaces, enter port group view.

Enable the interface to accept jumbo frames

jumboframe enable

Required

By default, an Ethernet interface accepts jumbo frames (up to 9216 bytes).

Port type Actions

No protective action is configured

A protective action is configured

Access interface

 Put the interface in controlled mode.

The interface discards all incoming packets, but still forwards outgoing traffic.

 Create traps.  Delete all MAC address entries of

the interface.

 Perform the configured protective

action.

 Create traps and log messages.  Delete all MAC address entries of the

interface.

Hybrid or trunk interface

 Create traps.  If loopback detection control is

enabled, set the interface in controlled mode. The interface discards all incoming packets, but still forwards outgoing packets.

 Delete all MAC address entries of

the interface.

 Create traps and log messages.  If loopback detection control is

enabled, take the configured protective action on the interface.

 Delete all MAC address entries of the

interface.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enable global loopback detection

loopback-detection enable

Required

Disabled by default.

Set the loopback detection interval

loopback-detection interval-time time

Optional

30 seconds by default.

Enabling single-port loopback detection on an Ethernet interface

If an interface receives a packet that it sent, a loop occurs. Loops might cause broadcast storms, degrading network performance. You can use loopback detection to detect loops on an interface and configure the protective action to take on the interface when a loop is detected, for example, to shut down the interface. In addition to the configured protective action, the switch also performs other actions to alleviate the impact of the loop condition, as described in Table 1.

Table 1 Actions to take upon detection of a loop condition

Follow these steps to configure single-port loopback detection:

To do…

Use the command…

Remarks

Enter Ethernet interface view or port group view

Enter Ethernet interface view

interface interface-type interface- number

Use either command.

To configure loopback detection on one interface, enter Ethernet interface view.

To configure loopback detection on a group of Ethernet interfaces, enter port group view.

Enter port group view

port-group manual port-group- name

Enable loopback detection on the interface

loopback-detection enable

Required

Disabled by default.

Enable loopback detection control

loopback-detection control enable

Optional

Disabled by default.

Enable loopback detection in all VLANs on the trunk or hybrid interface

loopback-detection per-vlan enable

Optional

By default, a trunk or hybrid interface performs loopback detection only in its PVID.

Set the protective action to take on the interface when a loop is detected

loopback-detection action { shutdown | semi-block | nolearning }

Optional

By default, a looped interface discards all incoming packets but still forwards outgoing packets. The system generates traps and deletes all MAC address entries of the looped interface.

With the shutdown keyword used, the switch shuts down looped Ethernet interfaces and sets their physical state to Loop down. When a looped interface recovers, you must use the undo shutdown command to restore its forwarding capability.

NOTE:

 To use single-port loopback detection on an Ethernet interface, you must enable the function both globally and

on the interface.

 To disable loopback detection on all interfaces, run the undo loopback-detection enable command in system

view.

 To enable a hybrid or trunk interface to take the administratively specified protective action, you must use the

loopback-detection control enable command on the interface.

 When you change the link type of an Ethernet interface by using the port link-type command, the switch

removes the protective action configured on the interface. For more information about the port link-type command, see the

Layer 2—LAN Switching Command Reference

Enabling multi-port loopback detection

When an interface receives packets sent from another interface on the same switch, a loop occurs between the two interfaces. Such a loop is called a "multi-port loop". As shown in Figure 5, if Port 1 receives packets sent out Port 2, a multi-port loop occurs between the two interfaces, and Port 1 (the

interface that receives the looped packets) is the looped interface. Multi-port loops might also cause

LAN

Port 1 Port 2

Switch A

Loop

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enable multi-port loopback detection

loopback-detection multi-portmode enable

Required

Disabled by default.

NOTE:

 To enable multi-port loopback detection, you must configure the loopback-detection multi-port-mode enable

and loopback-detection enable commands in system view, and configure the loopback-detection enable command in the view of the related interfaces.

 The single-port loopback detection function is available when the switch is performing multi-port loopback

detection.

NOTE:

Optical interfaces do not support the MDI mode setting.

broadcast storms.

Figure 5 Network diagram for multi-port loopback detection

The multi-port loopback detection function detects loops among interfaces on your switch. You can use the loopback-detection action command to configure the protective action to take on looped interfaces— for example, to shut down the interface, eliminating the loops. In addition, the switch also takes other link type-dependant actions on the looped interface (for example, Port 1 in Figure 5) to alleviate the impact of the loop condition. For more information, see ―Setting the statistics polling interval.‖

Multi-port loopback detection is implemented on the basis of single-port loopback detection configurations on Ethernet interfaces. To implement multi-port loopback detection, you must enable singleport loopback detection on one or multiple Ethernet interfaces on the switch.

Follow these steps to configure multi-port loopback detection:

Setting the MDI mode of an Ethernet interface

You can use both crossover and straight-through Ethernet cables to connect copper Ethernet interfaces. To accommodate these types of cables, a copper Ethernet interface can operate in one of the following Medium Dependent Interface (MDI) modes:

 Across mode  Normal mode  Auto mode

A copper Ethernet interface uses an RJ-45 connector, which comprises eight pins, each of which plays a

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Set the MDI mode of the Ethernet interface

mdi { across | auto | normal }

Optional

By default, a copper Ethernet interface operates in auto mode to negotiate pin roles with its peer.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Enable bridging on the Ethernet interface

port bridge enable

Required

Disabled by default.

dedicated role. For example, pins 1 and 2 transmit signals, and pins 3 and 6 receive signals. The pin role varies by the MDI modes as follows:

 In normal mode, pins 1 and 2 are transmit pins, and pins 3 and 6 are receive pins.  In across mode, pins 1 and 2 are receive pins, and pins 3 and 6 are transmit pins.  In auto mode, the interface negotiates pin roles with its peer.

To enable the interface to communicate with its peer, ensure that its transmit pins are connected to the remote receive pins. If the interface can detect the connection cable type, set the interface in auto MDI mode. If not, set its MDI mode by using the following guidelines:

 When a straight-through cable is used, set the interface to work in the MDI mode different than its

peer.

 When a crossover cable is used, set the interface to work in the same MDI mode as its peer, or set

either end to work in auto mode.

Follow these steps to set the MDI mode of an Ethernet interface:

Enabling bridging on an Ethernet interface

When an incoming packet arrives, the switch looks up the destination MAC address of the packet in the MAC address table. If an entry is found, but the outgoing interface is the same as the receiving interface (for example, if the destination and source MAC addresses of the packet are the same), the switch discards the packet.

To enable the switch to return such packets to the sender through the receiving interface rather than drop them, enable the bridging function on the Ethernet interface.

Follow these steps to enable bridging on an Ethernet interface:

Testing the cable connection of an Ethernet interface

NOTE:

 Optical interfaces do not support this feature.  If the link of an Ethernet interface is up, testing its cable connection will cause the link to come down and then go

up.

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter Ethernet interface view

interface interface-type interfacenumber

—

Test the cable connected to the Ethernet interface

virtual-cable-test

Required

To do…

Use the command…

Remarks

Display the current state of an interface and the related information

display interface [ interface-type [ interface- number ] ] [ | { begin | exclude | include } regular-expression ]

Available in any view

Display the summary of an interface

display interface [ interface-type [ interface- number ] ] brief [ | { begin | exclude |

include } regular-expression ]

display interface [ interface-type ] brief down [ | { begin | exclude | include }

regular-expression ]

Available in any view Display the statistics on the

packets that pass through a specific type of interfaces

display counters { inbound | outbound } interface [ interface-type ] [ | { begin | exclude | include } regular-expression ]

Available in any view

Display the statistics on the rate of the packets that pass through the interfaces that are of a specific type and are in the up state in the latest sampling interval

display counters rate { inbound | outbound } interface [ interface-type ] [ | { begin | exclude | include } regular-expression ]

Available in any view Display information about

discarded packets on an interface

display packet-drop interface [ interface-type [ interface-number ] ] [ | { begin | exclude | include } regular-expression ]

Available in any view

Display summary information about discarded packets on all interfaces

display packet-drop summary [ | { begin | exclude | include } regular-expression ]

Available in any view

Display information about a manual port group or all manual port groups

display port-group manual [ all | name port- group-name ] [ | { begin | exclude | include

} regular-expression ]

Available in any view

You can test the cable connection of an Ethernet interface for a short or open circuit. The device displays cable test results within five seconds. If any fault is detected, the test results include the length of the faulty cable segment.

Follow these steps to test the cable connection of an Ethernet interface:

Displaying and maintaining an Ethernet interface

To do…

Use the command…

Remarks

Display information about the loopback function

display loopback-detection [ | { begin | exclude | include } regular-expression ]

Available in any view

Display information about storm control on interfaces

display storm-constrain [ broadcast | multicast | unicast ] [ interface interface-type interface-number ] [ | { begin | exclude | include } regular-expression ]

Available in any view Clear the statistics of an interface

reset counters interface [ interface-type [ interface-number ] ]

Available in user view

Clear the statistics of discarded packets on an interface

reset packet-drop interface [ interface-type [ interface-number ] ]

Available in user view

Display the combo interfaces and the fiber and copper combo ports

display port combo [ | { begin | exclude | include } regular-expression ]

Available in any view

To do…

Use the command…

Remarks

Enter system view

system-view

—

Create a loopback interface and enter loopback interface view

interface loopback interface- number

—

Set a description for the loopback interface

description text

Optional

By default, the description of an interface is the interface name followed by the ―Interface‖ string.

Shut down the loopback interface

shutdown

Optional

By default, a loopback interface is up after it is created.

Loopback and null interface configuration

Loopback interface

Introduction to loopback interface

A loopback interface is a software-only virtual interface. It delivers the following benefits.

 The physical layer state and link-layer protocols of a loopback interface are always up unless the

loopback interface is manually shut down.

 To save IP address resources, you can assign an IP address with an all-F mask to a loopback

interface. When you assign an IPv4 address whose mask is not 32-bit, the system automatically changes the mask into a 32-bit mask. When you assign an IPv6 address whose mask is not 128-bit, the system automatically changes the mask into a 128-bit mask.

 You can enable routing protocols on a loopback interface, and a loopback interface can send and

receive routing protocol packets.

You can configure a loopback interface address as the source address of the IP packets that the switch generates. Because loopback interface addresses are stable unicast addresses, they are usually used as device identifications. When you configure a rule on an authentication or security server to permit or deny packets that a switch generates, you can simplify the rule by configuring it to permit or deny packets that carry the loopback interface address that identifies the switch. When you use a loopback interface address as the source address of IP packets, be sure to perform any necessary routing configuration to ensure that the route from the loopback interface to the peer is reachable. All data packets sent to the loopback interface are treated as packets sent to the switch itself, so the switch does not forward these packets.

Configuring a loopback interface

Follow these steps to configure a loopback interface:

NOTE:

You can configure settings such as IP addresses and IP routes on loopback interfaces. For more information, see the

Layer 3—IP Services Configuration Guide

and

Layer 3—IP Routing Configuration

Guide

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter null interface view

interface null 0

Required

The Null 0 interface is the default null interface on your switch. It cannot be manually created or removed.

Set a description for the null interface

description text

Optional

By default, the description of an interface is

the interface name followed by the ―Interface‖

string.

To do…

Use the command…

Remarks

Display information about loopback interfaces

display interface loopback [ brief [ down ] ] [ | { begin | exclude | include } regular-expression ]

display interface loopback interface-number [ brief ] [ | { begin | exclude | include } regular-expression ]

Available in any view

Null interface

Introduction to null interface

A null interface is a completely software-based logical interface, and is always up. However, you cannot use it to forward data packets or configure an IP address or link-layer protocol on it. With a null interface specified as the next hop of a static route to a specific network segment, any packets routed to the network segment are dropped. The null interface provides a simpler way to filter packets than ACL. You can filter uninteresting traffic by transmitting it to a null interface instead of applying an ACL.

For example, by executing the ip route-static 92.101.0.0 255.255.0.0 null 0 command (which configures a static route that leads to null interface 0), you can have all the packets destined to the network segment

92.101.0.0/16 discarded.

Only one null interface, Null 0, is supported on your switch. You cannot remove or create a null interface.

Configuring null 0 interface

Follow these steps to enter null interface view:

Displaying and maintaining loopback and null interfaces

To do…

Use the command…

Remarks

Display information about the null interface

display interface null [ brief [ down ] ] [ | { begin | exclude | include } regular-expression ]

display interface null 0 [ brief ] [ | { begin | exclude

| include } regular-expression ]

Available in any view Clear the statistics on a

loopback interface

reset counters interface [ loopback [ interface-number ] ]

Available in user view

Clear the statistics on the null interface

reset counters interface [ null [ 0 ] ]

Available in user view

MAC address table configuration

Overview

Every Ethernet switch maintains a MAC address table for forwarding frames through unicast instead of broadcast. This table describes from which port a MAC address (or host) can be reached. When forwarding a frame, the switch first looks up the MAC address of the frame in the MAC address table for a match. If the switch finds an entry, it forwards the frame out of the outgoing port in the entry. If the switch does not find an entry, it broadcasts the frame out of all but the incoming port.

How a MAC address table entry is created

The switch automatically obtains entries in the MAC address table, or you can add them manually.

MAC address learning

The switch can automatically populate its MAC address table by obtaining the source MAC addresses (called ―MAC address learning‖) of incoming frames on each port.

When a frame arrives at a port, Port A for example, the switch performs the following tasks:

1. Verifies the source MAC address (for example, MAC-SOURCE) of the frame.

2. Looks up the MAC address in the MAC address table.

3. Updates an entry if it finds one. If the switch does not find an entry, it adds an entry for MAC-

SOURCE and Port A.

The switch performs the learning process each time it receives a frame from an unknown source MAC address, until the MAC address table is fully populated.

After obtaining the source MAC address of a frame, the switch looks up the destination MAC address in the MAC address table. If the switch finds an entry for the MAC address, it forwards the frame out of the specific outgoing port, Port A in this example.

Manually configuring MAC address entries

With dynamic MAC address learning, a switch does not distinguish between illegitimate and legitimate frames, which can invite security hazards. For example, if a hacker sends frames with a forged source MAC address to a port different from the one that the real MAC address is connected to, the switch will create an entry for the forged MAC address, and forward frames destined for the legal user to the hacker instead.

To enhance the security of a port, you can bind specific user devices to the port by manually adding MAC address entries into the MAC address table of the switch. Because manually configured entries have higher priority than dynamically obtained ones, you can prevent hackers from stealing data using forged MAC addresses.

Types of MAC address table entries

A MAC address table can contain the following types of entries:

 Static entries, which are manually added and never age out.

NOTE:

A static or blackhole MAC address entry can overwrite a dynamic MAC address entry, but not vice versa.

NOTE:

 The MAC address table can contain only Layer 2 Ethernet ports and Layer 2 aggregate interfaces.  This document covers configuring static, dynamic, and blackhole unicast MAC address table entries. For more

information about static multicast MAC address table entries, see the

IP Multicast Configuration Guide

 Dynamic entries, which can be manually added or dynamically obtained and might age out.  Blackhole entries, which are manually configured and never age out. Blackhole entries are

configured for filtering out frames with specific destination MAC addresses. For example, to block all packets destined for a specific user for security concerns, you can configure the MAC address of this user as a blackhole destination MAC address entry.

To adapt to network changes and prevent inactive entries from occupying table space, an aging mechanism is adopted for dynamic MAC address entries. Each time a dynamic MAC address entry obtained or created, an aging time starts. If the entry has not updated when the aging timer expires, the switch deletes the entry. If the entry has updated before the aging timer expires, the aging timer restarts.

MAC address table-based frame forwarding

When forwarding a frame, the switch adopts the following forwarding modes based on the MAC address table:

 Unicast mode: If an entry is available for the destination MAC address, the switch forwards the

frame out of the outgoing interface indicated by the MAC address table entry.

 Broadcast mode: If the switch receives a frame with the destination address as all ones, or no entry

is available for the destination MAC address, the switch broadcasts the frame to all the interfaces except the receiving interface.

Configuring the MAC address table

The MAC address table configuration tasks include:

 Manually configuring MAC address table entries  Disabling MAC address learning  Configuring the aging timer for dynamic MAC address entries  Configuring the MAC learning limit on ports

These configuration tasks are all optional and can be performed in any order.

Manually configuring MAC address table entries

To help prevent MAC address spoofing attacks and improve port security, you can manually add MAC address table entries to bind ports with MAC addresses. You can also configure blackhole MAC address entries to filter out packets with certain source or destination MAC addresses.

Follow these steps to add, modify, or remove entries in the MAC address table in system view:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Configure MAC address table entries

Configure static or dynamic MAC address table entries

mac-address { dynamic | static } macaddress interface interface-type interface-number vlan vlan-id

Required

Use either command.

Make sure that you have created the VLAN and assign the interface to the VLAN.

Configure blackhole MAC address table entries

mac-address blackhole mac-address vlan vlan-id

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enter interface view

interface interface-type interfacenumber

—

Configure a MAC address table entry

mac-address { dynamic | static } mac-address vlan vlan-id

Required

Ensure that you have created the VLAN and assign the interface to the VLAN

To do…

Use the command…

Remarks

Enter system view

system-view

—

Disable global MAC address learning

mac-address mac-learning disable

Required

Enabled by default.

NOTE:

When MAC address learning is disabled, the obtained MAC addresses remain valid until they age out.

Follow these steps to add or modify a MAC address table entry in interface view:

Disabling MAC address learning

Sometimes, you might need to disable MAC address learning to prevent the MAC address table from being saturated, for example, when your switch is being attacked by a large amount of packets with different source MAC addresses.

Disabling global MAC address learning

Disabling global MAC address learning disables the learning function on all ports.

Follow these steps to disable MAC address learning:

Disabling MAC address learning on ports

After enabling global MAC address learning, you can disable the function on a single port, or on all ports in a port group as needed.

Follow these steps to disable MAC address learning on an interface or a port group:

To do…

Use the command…

Remarks

Enter system view

system-view

—

Enable global MAC address learning

undo mac-address mac-learning disable

Optional

Enabled by default.

Enter interface view or port group view

Enter Layer 2 Ethernet interface view or Layer 2 aggregate interface view

interface interface-type interfacenumber

Required

Use either command.

The configuration made in Layer 2 Ethernet or Layer 2 aggregate interface view takes effect on the current interface only. The configuration made in port group view takes effect on all the member ports in the port group.

Enter port group view

port-group manual port-group- name

Disable MAC address learning on the interface or all ports in the port group

mac-address mac-learning disable

Required

Enabled by default.

NOTE:

 When MAC address learning is disabled, the obtained MAC addresses remain valid until they age out.  For more information about port groups, see the chapter ―Ethernet interface configuration.‖

To do…

Use the command…

Remarks

Enter system view

system-view

—

Configure the aging timer for dynamic MAC address entries

mac-address timer { aging seconds | no-aging }

Optional

300 seconds by default.

Configuring the aging timer for dynamic MAC address entries

The MAC address table uses an aging timer for dynamic MAC address entries for security and efficient use of table space. If a dynamic MAC address entry has failed to update before the aging timer expires, the switch deletes the entry. This aging mechanism ensures that the MAC address table can quickly update to accommodate the latest network changes.

Set the aging timer appropriately. A long aging interval might cause the MAC address table to retain outdated entries, exhaust the MAC address table resources, and fail to update its entries to accommodate the latest network changes. A short interval might result in the removal of valid entries and unnecessary broadcasts, which might affect device performance.

Follow these steps to configure the aging timer for dynamic MAC address entries:

You can reduce broadcasts on a stable network by disabling the aging timer to prevent dynamic entries from unnecessarily aging out. By reducing broadcasts, you improve not only network performance, but also security, because you reduce the chances that a data packet will reach unintended destinations.

+ 167 hidden pages

HP A5120 EI Configuration Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Ethernet interface configuration

Ethernet interface naming conventions

Configuring basic settings of an Ethernet interface

Configuring a combo interface

Introduction to combo interfaces

Configuration prerequisites

Changing the active port of a combo interface

Configuring basic settings of an Ethernet interface

Setting speed options for auto negotiation on an Ethernet interface

Configuring generic flow control on an Ethernet interface

Configuring link change suppression on an Ethernet interface

Configuring link-down suppression

Configuring link-up suppression

Configuring loopback testing on an Ethernet interface

Configuring a port group

Configuring traffic storm protection

Configuring storm suppression on an Ethernet interface

Configuring storm control on an Ethernet interface

Setting the statistics polling interval

Enabling the auto power-down function on an Ethernet interface

Configuring jumbo frame support

Enabling single-port loopback detection on an Ethernet interface

Enabling multi-port loopback detection

Setting the MDI mode of an Ethernet interface

Enabling bridging on an Ethernet interface

Testing the cable connection of an Ethernet interface

Displaying and maintaining an Ethernet interface

Loopback and null interface configuration

Loopback interface

Introduction to loopback interface

Configuring a loopback interface

Null interface

Introduction to null interface

Configuring null 0 interface

Displaying and maintaining loopback and null interfaces

MAC address table configuration

Overview

How a MAC address table entry is created

MAC address learning

1. Verifies the source MAC address (for example, MAC-SOURCE) of the frame.

2. Looks up the MAC address in the MAC address table.

Manually configuring MAC address entries

Types of MAC address table entries

MAC address table-based frame forwarding

Configuring the MAC address table

Manually configuring MAC address table entries

Disabling MAC address learning

Disabling global MAC address learning

Disabling MAC address learning on ports

Configuring the aging timer for dynamic MAC address entries