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Brocade Communications Systems
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ICX 7250 Series
Configuration Manual
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Brocade Communications Systems ICX 7250 Series, ICX 7450 Series, ICX 7750 Series Configuration Manual

CONFIGURATION GUIDE
Brocade FastIron Layer 3 Routing Conguration Guide
Supporting FastIron Software Release 8.0.40a
53-1003903-04 20 December 2016
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Preface................................................................................................................................................................................................................................17
Document conventions.........................................................................................................................................................................................................................17
Text formatting conventions......................................................................................................................................................................................................17
Command syntax conventions.................................................................................................................................................................................................17
Notes, cautions, and warnings..................................................................................................................................................................................................18
Brocade resources..................................................................................................................................................................................................................................18
Contacting Brocade Technical Support......................................................................................................................................................................................... 19
Brocade customers.......................................................................................................................................................................................................................19
Brocade OEM customers..........................................................................................................................................................................................................19
Document feedback.............................................................................................................................................................................................................................. 19
About This Document..................................................................................................................................................................................................... 21
Supported hardware and software...................................................................................................................................................................................................21
What’s new in this document............................................................................................................................................................................................................. 21
How command information is presented in this guide............................................................................................................................................................22
ARP - Address Resolution Protocol............................................................................................................................................................................. 23
ARP parameter conguration............................................................................................................................................................................................................ 23
How ARP works.............................................................................................................................................................................................................................23
Rate limiting ARP packets..........................................................................................................................................................................................................24
Changing the ARP aging period..............................................................................................................................................................................................25
Enabling proxy ARP......................................................................................................................................................................................................................25
Creating static ARP entries........................................................................................................................................................................................................26
ARP Packet Validation.................................................................................................................................................................................................................28
Ingress ARP packet priority.......................................................................................................................................................................................................28
Displaying the ARP table ....................................................................................................................................................................................................................29
Reverse Address Resolution Protocol conguration................................................................................................................................................................29
How RARP Diers from BootP and DHCP....................................................................................................................................................................... 29
Disabling RARP..............................................................................................................................................................................................................................30
Creating static RARP entries.....................................................................................................................................................................................................30
Changing the maximum number of static RARP entries supported....................................................................................................................... 30
Dynamic ARP inspection ....................................................................................................................................................................................................................31
ARP poisoning................................................................................................................................................................................................................................31
Dynamic ARP Inspection........................................................................................................................................................................................................... 31
Conguration notes and feature limitations for DAI........................................................................................................................................................32
Dynamic ARP Inspection conguration...............................................................................................................................................................................33
Multi-VRF support for DAI........................................................................................................................................................................................................34
Displaying ARP inspection status and ports......................................................................................................................................................................35
IP Addressing.................................................................................................................................................................................................................... 37
IP addressing overview.........................................................................................................................................................................................................................37
IP conguration overview.....................................................................................................................................................................................................................37
Full Layer 3 support.....................................................................................................................................................................................................................37
IP interfaces......................................................................................................................................................................................................................................38
IP packet ow through a Layer 3 switch.............................................................................................................................................................................. 39
IP route exchange protocols......................................................................................................................................................................................................42
IP multicast protocols...................................................................................................................................................................................................................43
IP interface redundancy protocols..........................................................................................................................................................................................43
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ACLs and IP access policies.....................................................................................................................................................................................................43
Basic IP parameters and defaults - Layer 3 switches.............................................................................................................................................................44
When parameter changes take eect....................................................................................................................................................................................44
IP global parameters - Layer 3 switches.............................................................................................................................................................................44
IP interface parameters - Layer 3 switches........................................................................................................................................................................48
Basic IP parameters and defaults - Layer 2 switches.............................................................................................................................................................49
IP global parameters - Layer 2 switches.............................................................................................................................................................................49
Interface IP parameters - Layer 2 switches........................................................................................................................................................................51
Basic IP conguration........................................................................................................................................................................................................................... 51
Conguring IP parameters - Layer 3 switches...........................................................................................................................................................................51
Conguring IP addresses...........................................................................................................................................................................................................51
Conguring 31-bit subnet masks on point-to-point networks..................................................................................................................................55
Conguring DNS resolver..........................................................................................................................................................................................................56
Conguring packet parameters................................................................................................................................................................................................59
Changing the router ID................................................................................................................................................................................................................62
Specifying a single source interface for specied packet types.................................................................................................................................62
Conguring delay time for notifying VE down event......................................................................................................................................................65
Conguring forwarding parameters....................................................................................................................................................................................... 66
Disabling ICMP messages........................................................................................................................................................................................................ 68
Enabling ICMP redirect messages.........................................................................................................................................................................................70
Conguring a default network route.......................................................................................................................................................................................70
Conguring IP load sharing.......................................................................................................................................................................................................71
ECMP load sharing for IPv6.....................................................................................................................................................................................................75
ICMP Router Discovery Protocol conguration................................................................................................................................................................76
IRDP parameters........................................................................................................................................................................................................................... 77
Conguring UDP broadcast and IP helper parameters.................................................................................................................................................78
Conguring IP parameters - Layer 2 switches...........................................................................................................................................................................80
Conguring the management IP address and specifying the default gateway................................................................................................... 80
Conguring Domain Name System resolver.....................................................................................................................................................................81
Changing the TTL threshold.....................................................................................................................................................................................................83
IPv4 point-to-point GRE tunnels ....................................................................................................................................................................................................84
IPv4 GRE tunnel overview.........................................................................................................................................................................................................84
GRE packet structure and header format............................................................................................................................................................................84
Path MTU Discovery support...................................................................................................................................................................................................85
Support for IPv4 multicast routing over GRE tunnels....................................................................................................................................................86
Conguration considerations for GRE IP tunnels.............................................................................................................................................................86
Conguration tasks for GRE tunnels.....................................................................................................................................................................................87
Example point-to-point GRE tunnel conguration..........................................................................................................................................................93
Displaying GRE tunneling information..................................................................................................................................................................................94
Clearing GRE statistics................................................................................................................................................................................................................98
Bandwidth for IP interfaces.................................................................................................................................................................................................................99
Limitations and pre-requisites...............................................................................................................................................................................................100
OSPF cost calculation with interface bandwidth...........................................................................................................................................................100
Setting the bandwidth value for an Ethernet interface.................................................................................................................................................100
Setting the bandwidth value for a VE interface..............................................................................................................................................................101
Setting the bandwidth value for a tunnel interface........................................................................................................................................................102
User-congurable MAC address per IP interface.................................................................................................................................................................. 102
Manually conguring an IP MAC address........................................................................................................................................................................103
Modifying and displaying Layer 3 system parameter limits..............................................................................................................................................104
Layer 3 conguration notes...................................................................................................................................................................................................104
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Displaying Layer 3 system parameter limits...................................................................................................................................................................104
Enabling or disabling routing protocols...................................................................................................................................................................................... 105
Enabling or disabling Layer 2 switching.....................................................................................................................................................................................106
Conguration notes and feature limitations for Layer 2 switching.........................................................................................................................106
Command syntax for Layer 2 switching...........................................................................................................................................................................106
Conguring a Layer 3 Link Aggregration Group (LAG).......................................................................................................................................................106
Disabling IP checksum check.........................................................................................................................................................................................................107
Displaying IP conguration information and statistics..........................................................................................................................................................108
Changing the network mask display to prex format.................................................................................................................................................. 108
Displaying IP information - Layer 3 switches.................................................................................................................................................................108
Displaying IP information - Layer 2 switches.................................................................................................................................................................119
IPv6 Addressing.............................................................................................................................................................................................................125
IPv6 addressing overview................................................................................................................................................................................................................125
IPv6 address types....................................................................................................................................................................................................................126
IPv6 stateless auto-conguration........................................................................................................................................................................................127
Full Layer 3 IPv6 feature support.................................................................................................................................................................................................128
IPv6 CLI command support ..........................................................................................................................................................................................................128
IPv6 host address on a Layer 2 switch.......................................................................................................................................................................................130
Conguring a global or site-local IPv6 address with a manually congured interface ID............................................................................131
Conguring a link-local IPv6 address as a system-wide address for a switch.................................................................................................131
Conguring the management port for an IPv6 automatic address conguration....................................................................................................132
Conguring basic IPv6 connectivity on a Layer 3 switch...................................................................................................................................................132
Enabling IPv6 routing............................................................................................................................................................................................................... 132
IPv6 conguration on each router interface.................................................................................................................................................................... 132
Conguring IPv4 and IPv6 protocol stacks.....................................................................................................................................................................135
IPv6 over IPv4 tunnels......................................................................................................................................................................................................................136
IPv6 over IPv4 tunnel conguration notes...................................................................................................................................................................... 136
Conguring a manual IPv6 tunnel.......................................................................................................................................................................................136
Clearing IPv6 tunnel statistics............................................................................................................................................................................................... 137
Displaying IPv6 tunnel information.....................................................................................................................................................................................138
Displaying a summary of tunnel information..................................................................................................................................................................138
Displaying interface level IPv6 settings.............................................................................................................................................................................138
IPv6 management (IPv6 host support)......................................................................................................................................................................................139
Conguring IPv6 management ACLs...............................................................................................................................................................................139
Restricting SNMP access to an IPv6 node..................................................................................................................................................................... 139
Specifying an IPv6 SNMP trap receiver...........................................................................................................................................................................140
Conguring SNMP V3 over IPv6........................................................................................................................................................................................140
Secure Shell, SCP, and IPv6..................................................................................................................................................................................................140
IPv6 Telnet.....................................................................................................................................................................................................................................140
IPv6 traceroute............................................................................................................................................................................................................................141
IPv6 Web management using HTTP and HTTPS.......................................................................................................................................................141
Restricting Web management access................................................................................................................................................................................142
Restricting Web management access by specifying an IPv6 ACL.......................................................................................................................142
Restricting Web management access to an IPv6 host...............................................................................................................................................142
Conguring name-to-IPv6 address resolution using IPv6 DNS resolver..........................................................................................................142
Dening an IPv6 DNS entry.................................................................................................................................................................................................. 142
Pinging an IPv6 address......................................................................................................................................................................................................... 143
Conguring an IPv6 Syslog server......................................................................................................................................................................................144
Viewing IPv6 SNMP server addresses.............................................................................................................................................................................144
Disabling router advertisement and solicitation messages.......................................................................................................................................145
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Disabling IPv6 on a Layer 2 switch.................................................................................................................................................................................... 145
IPv6 ICMP feature conguration...................................................................................................................................................................................................145
Conguring ICMP rate limiting..............................................................................................................................................................................................146
Enabling IPv6 ICMP redirect messages...........................................................................................................................................................................146
IPv6 neighbor discovery conguration.......................................................................................................................................................................................147
IPv6 neighbor discovery conguration notes.................................................................................................................................................................147
Neighbor solicitation and advertisement messages....................................................................................................................................................147
Router advertisement and solicitation messages......................................................................................................................................................... 148
Neighbor redirect messages..................................................................................................................................................................................................148
Setting neighbor solicitation parameters for duplicate address detection..........................................................................................................148
Setting IPv6 router advertisement parameters..............................................................................................................................................................149
Prexes advertised in IPv6 router advertisement messages...................................................................................................................................150
Setting ags in IPv6 router advertisement messages................................................................................................................................................ 151
Enabling and disabling IPv6 router advertisements....................................................................................................................................................152
IPv6 router advertisement preference support..............................................................................................................................................................152
Conguring reachable time for remote IPv6 nodes.....................................................................................................................................................152
IPv6 neighbor discovery inspection.............................................................................................................................................................................................153
Neighbor discovery inspection conguration................................................................................................................................................................. 156
Syslog message for ND inspection.................................................................................................................................................................................... 156
IPv6 MTU............................................................................................................................................................................................................................................... 156
Conguration notes and feature limitations for IPv6 MTU.......................................................................................................................................156
Changing the IPv6 MTU......................................................................................................................................................................................................... 157
Static neighbor entries conguration...........................................................................................................................................................................................157
Limiting the number of hops an IPv6 packet can traverse.................................................................................................................................................158
IPv6 source routing security enhancements............................................................................................................................................................................158
TCAM space conguration.............................................................................................................................................................................................................. 158
Allocating TCAM space............................................................................................................................................................................................................159
Allocating TCAM space for GRE tunnels.........................................................................................................................................................................160
Displaying global IPv6 information..............................................................................................................................................................................................161
Displaying IPv6 cache information.....................................................................................................................................................................................161
Displaying IPv6 interface information................................................................................................................................................................................162
Displaying IPv6 neighbor information...............................................................................................................................................................................163
Displaying the IPv6 route table ............................................................................................................................................................................................164
Displaying local IPv6 routers.................................................................................................................................................................................................166
Displaying IPv6 TCP information........................................................................................................................................................................................166
Displaying IPv6 trac statistics............................................................................................................................................................................................169
Clearing global IPv6 information...................................................................................................................................................................................................172
Clearing the IPv6 cache...........................................................................................................................................................................................................172
Clearing IPv6 neighbor information....................................................................................................................................................................................172
Clearing IPv6 routes from the IPv6 route table.............................................................................................................................................................173
Clearing IPv6 trac statistics................................................................................................................................................................................................ 173
IPv4 Static Routing....................................................................................................................................................................................................... 175
Static routes conguration................................................................................................................................................................................................................175
Static route types........................................................................................................................................................................................................................ 175
Static IP route parameters.......................................................................................................................................................................................................175
Multiple static routes to the same destination provide load sharing and redundancy...................................................................................176
Static route states follow port states................................................................................................................................................................................... 176
Conguring a static IP route...................................................................................................................................................................................................177
Static route next hop resolution............................................................................................................................................................................................ 178
Naming a static IP route...........................................................................................................................................................................................................178
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Removing a name or a static route..................................................................................................................................................................................... 179
Static route recursive lookup..................................................................................................................................................................................................180
Static route resolve by default route....................................................................................................................................................................................180
Conguring a "Null" route........................................................................................................................................................................................................180
Conguring load balancing and redundancy using multiple static routes to the same destination......................................................... 181
Conguring standard static IP routes and interface or null static routes to the same destination............................................................ 182
IPv6 Static Routing....................................................................................................................................................................................................... 185
Static IPv6 route conguration.......................................................................................................................................................................................................185
Conguring a static IPv6 route.......................................................................................................................................................................................................185
Conguring a static route in a non-default VRF or User VRF.......................................................................................................................................... 186
RIP.....................................................................................................................................................................................................................................189
RIP overview.......................................................................................................................................................................................................................................... 189
RIP parameters and defaults...........................................................................................................................................................................................................189
RIP global parameters..............................................................................................................................................................................................................189
RIP interface parameters.........................................................................................................................................................................................................191
Conguring RIP parameters............................................................................................................................................................................................................191
Enabling RIP.................................................................................................................................................................................................................................191
Conguring route costs............................................................................................................................................................................................................192
Changing the administrative distance................................................................................................................................................................................192
Conguring redistribution........................................................................................................................................................................................................192
Conguring route learning and advertising parameters............................................................................................................................................. 194
Changing the route loop prevention method..................................................................................................................................................................195
Suppressing RIP route advertisement on a VRRP or VRRPE backup interface.............................................................................................196
Conguring RIP route lters using prex-lists and route maps...............................................................................................................................196
Setting RIP timers.......................................................................................................................................................................................................................198
Displaying RIP Information..............................................................................................................................................................................................................198
Displaying CPU utilization statistics.............................................................................................................................................................................................200
RIPng................................................................................................................................................................................................................................203
RIPng Overview....................................................................................................................................................................................................................................203
Conguring RIPng...............................................................................................................................................................................................................................203
Enabling RIPng............................................................................................................................................................................................................................203
Conguring RIPng timers........................................................................................................................................................................................................204
Conguring route learning and advertising parameters............................................................................................................................................. 205
Redistributing routes into RIPng...........................................................................................................................................................................................206
Controlling distribution of routes through RIPng...........................................................................................................................................................207
Conguring poison reverse parameters............................................................................................................................................................................207
Clearing RIPng routes from IPv6 route table...........................................................................................................................................................................208
Displaying RIPng information.........................................................................................................................................................................................................208
Displaying RIPng conguration............................................................................................................................................................................................208
Displaying RIPng routing table..............................................................................................................................................................................................209
OSPFv2........................................................................................................................................................................................................................... 211
OSPFv2 overview................................................................................................................................................................................................................................211
Autonomous System..........................................................................................................................................................................................................................211
OSPFv2 components and roles....................................................................................................................................................................................................212
Area Border Routers..................................................................................................................................................................................................................212
Autonomous System Boundary Routers......................................................................................................................................................................... 212
Designated routers.....................................................................................................................................................................................................................213
Reduction of equivalent AS external LSAs................................................................................................................................................................................214
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Algorithm for AS external LSA reduction...................................................................................................................................................................................216
OSPFv2 areas.......................................................................................................................................................................................................................................216
Backbone area.............................................................................................................................................................................................................................216
Area types......................................................................................................................................................................................................................................216
Area range..................................................................................................................................................................................................................................... 217
Stub area and totally stubby area.........................................................................................................................................................................................217
Not-so-stubby area (NSSA)...................................................................................................................................................................................................217
Link state advertisements....................................................................................................................................................................................................... 218
Virtual links..............................................................................................................................................................................................................................................219
Default route origination....................................................................................................................................................................................................................220
External route summarization.........................................................................................................................................................................................................220
SPF timers..............................................................................................................................................................................................................................................221
OSPFv2 LSA refreshes.................................................................................................................................................................................................................... 221
Support for OSPF RFC 2328 Appendix E..............................................................................................................................................................................222
OSPFv2 graceful restart................................................................................................................................................................................................................... 223
OSPFv2 stub router advertisement.............................................................................................................................................................................................223
OSPFv2 Shortest Path First throttling........................................................................................................................................................................................224
IETF RFC and internet draft support...........................................................................................................................................................................................224
OSPFv2 non-stop routing...............................................................................................................................................................................................................224
Limitations of NSR.....................................................................................................................................................................................................................225
Synchronization of critical OSPFv2 elements.........................................................................................................................................................................225
Link state database synchronization...................................................................................................................................................................................225
LSA delayed acknowledging..................................................................................................................................................................................................225
LSA syncing and packing ...................................................................................................................................................................................................... 226
Neighbor device synchronization.........................................................................................................................................................................................226
Synchronization limitations.....................................................................................................................................................................................................226
Interface synchronization.........................................................................................................................................................................................................226
Standby module operations............................................................................................................................................................................................................ 226
Neighbor database.....................................................................................................................................................................................................................227
LSA database...............................................................................................................................................................................................................................227
OSPFv2 distribute list........................................................................................................................................................................................................................227
Conguring an OSPFv2 distribution list using ACLs .................................................................................................................................................227
Conguring an OSPFv2 distribution list using route maps .....................................................................................................................................228
OSPFv2 route redistribution...........................................................................................................................................................................................................229
Load sharing.......................................................................................................................................................................................................................................... 230
Interface types to which the reference bandwidth does not apply...................................................................................................................................232
Changing the reference bandwidth for the cost on OSPFv2 interfaces....................................................................................................................... 232
OSPFv2 over VRF..............................................................................................................................................................................................................................233
Conguring OSPFv2..........................................................................................................................................................................................................................233
Enabling OSPFv2......................................................................................................................................................................................................................233
Assigning OSPFv2 areas........................................................................................................................................................................................................233
Conguring an NSSA................................................................................................................................................................................................................234
Conguring a summary-address for the NSSA............................................................................................................................................................ 234
Disabling summary LSAs for a stub area.........................................................................................................................................................................235
Assigning an area range...........................................................................................................................................................................................................235
Assigning interfaces to an area.............................................................................................................................................................................................236
Conguring virtual links............................................................................................................................................................................................................236
Modifying Shortest Path First timers..................................................................................................................................................................................237
Conguring the OSPFv2 LSA pacing interval............................................................................................................................................................... 238
Disabling OSPFv2 graceful restart..................................................................................................................................................................................... 238
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Re-enabling OSPFv2 graceful restart............................................................................................................................................................................... 238
Disabling OSPFv2 graceful restart helper....................................................................................................................................................................... 239
Redistributing routes into OSPFv2.....................................................................................................................................................................................239
Conguring the OSPFv2 Max-Metric Router LSA...................................................................................................................................................... 240
Enabling OSPFv2 in a non-default VRF..........................................................................................................................................................................240
Changing default settings........................................................................................................................................................................................................241
Disabling and re-enabling OSPFv2 event logging...................................................................................................................................................... 241
Disabling OSPFv2 on the device........................................................................................................................................................................................241
OSPFv3........................................................................................................................................................................................................................... 243
OSPFv3 overview................................................................................................................................................................................................................................243
OSPFv3 areas.......................................................................................................................................................................................................................................244
Backbone area.............................................................................................................................................................................................................................244
Area types......................................................................................................................................................................................................................................244
Area range..................................................................................................................................................................................................................................... 245
Stub area and totally stubby area.........................................................................................................................................................................................245
Not-so-stubby area...................................................................................................................................................................................................................245
LSA types for OSPFv3............................................................................................................................................................................................................246
Virtual links..............................................................................................................................................................................................................................................246
Virtual link source address assignment.............................................................................................................................................................................248
OSPFv3 route redistribution...........................................................................................................................................................................................................248
Default route origination....................................................................................................................................................................................................................249
Filtering OSPFv3 routes...................................................................................................................................................................................................................249
SPF timers..............................................................................................................................................................................................................................................249
OSPFv3 administrative distance...................................................................................................................................................................................................250
OSPFv3 LSA refreshes.................................................................................................................................................................................................................... 250
External route summarization.........................................................................................................................................................................................................251
OSPFv3 over VRF..............................................................................................................................................................................................................................251
OSPFv3 graceful restart helper.....................................................................................................................................................................................................251
OSPFv3 non-stop routing...............................................................................................................................................................................................................252
IPsec for OSPFv3...............................................................................................................................................................................................................................252
IPsec for OSPFv3 conguration..........................................................................................................................................................................................253
IPsec for OSPFv3 considerations.......................................................................................................................................................................................253
Conguring OSPFv3..........................................................................................................................................................................................................................254
Conguring the router ID.........................................................................................................................................................................................................254
Enabling OSPFv3......................................................................................................................................................................................................................254
Enabling OSPFv3 in a non-default VRF..........................................................................................................................................................................255
Assigning OSPFv3 areas........................................................................................................................................................................................................256
Assigning OSPFv3 areas in a non-default VRF........................................................................................................................................................... 256
Assigning OSPFv3 areas to interfaces............................................................................................................................................................................. 257
Assigning a stub area................................................................................................................................................................................................................258
Conguring an NSSA................................................................................................................................................................................................................259
Conguring virtual links............................................................................................................................................................................................................259
Redistributing routes into OSPFv3.....................................................................................................................................................................................260
Modifying SPF timers...............................................................................................................................................................................................................261
Conguring the OSPFv3 LSA pacing interval............................................................................................................................................................... 261
Conguring default external routes..................................................................................................................................................................................... 262
Disabling and re-enabling OSPFv3 event logging...................................................................................................................................................... 262
Conguring administrative distance based on route type......................................................................................................................................... 263
Changing the reference bandwidth for the cost on OSPFv3 interfaces..............................................................................................................263
Setting all OSPFv3 interfaces to the passive state.......................................................................................................................................................264
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Disabling OSPFv3 graceful restart helper....................................................................................................................................................................... 264
Re-enabling OSPFv3 graceful restart helper................................................................................................................................................................. 265
Conguring IPsec on an OSPFv3 area.............................................................................................................................................................................265
Conguring IPsec on an OSPFv3 interface....................................................................................................................................................................266
Conguring IPsec on OSPFv3 virtual links.....................................................................................................................................................................267
Specifying the key rollover timer..........................................................................................................................................................................................267
Clearing IPsec statistics........................................................................................................................................................................................................... 268
Displaying OSPFv3 results.................................................................................................................................................................................................... 269
Conguring BGP4 (IPv4).............................................................................................................................................................................................273
BGP4 overview.....................................................................................................................................................................................................................................273
Relationship between the BGP4 route table and the IP route table......................................................................................................................274
How BGP4 selects a path for a route (BGP best path selection algorithm)......................................................................................................275
BGP4 message types.............................................................................................................................................................................................................. 276
Grouping of RIB-out peers.....................................................................................................................................................................................................278
Implementation of BGP4.................................................................................................................................................................................................................278
BGP4 restart..........................................................................................................................................................................................................................................278
BGP4 Peer notication during a management module switchover......................................................................................................................279
BGP4 neighbor local AS.........................................................................................................................................................................................................280
Basic conguration and activation for BGP4...........................................................................................................................................................................282
Disabling BGP4.......................................................................................................................................................................................................................... 283
BGP4 parameters................................................................................................................................................................................................................................283
Parameter changes that take eect immediately.......................................................................................................................................................... 285
Parameter changes that take eect after resetting neighbor sessions.................................................................................................................285
Parameter changes that take eect after disabling and re-enabling redistribution.........................................................................................286
Memory considerations.....................................................................................................................................................................................................................286
Memory conguration options obsoleted by dynamic memory............................................................................................................................286
Basic conguration tasks required for BGP4...........................................................................................................................................................................286
Enabling BGP4 on the device...............................................................................................................................................................................................286
Changing the device ID............................................................................................................................................................................................................287
Setting the local AS number.................................................................................................................................................................................................. 287
Adding a loopback interface...................................................................................................................................................................................................288
Adding BGP4 neighbors.........................................................................................................................................................................................................289
Adding a BGP4 peer group...................................................................................................................................................................................................296
Optional BGP4 conguration tasks.............................................................................................................................................................................................299
Changing the Keep Alive Time and Hold Time..............................................................................................................................................................299
Changing the BGP4 next-hop update timer...................................................................................................................................................................299
Enabling fast external fallover................................................................................................................................................................................................300
Changing the maximum number of paths for BGP4 Multipath load sharing...................................................................................................300
Customizing BGP4 Multipath load sharing.....................................................................................................................................................................301
Specifying a list of networks to advertise......................................................................................................................................................................... 302
Changing the default local preference................................................................................................................................................................................303
Using the IP default route as a valid next-hop for a BGP4 route...........................................................................................................................303
Changing the default MED (Metric) used for route redistribution...........................................................................................................................304
Enabling next-hop recursion..................................................................................................................................................................................................304
Changing administrative distances......................................................................................................................................................................................306
Requiring the rst AS to be the neighbor AS..................................................................................................................................................................307
Disabling or re-enabling comparison of the AS-Path length...................................................................................................................................308
Enabling or disabling comparison of device IDs...........................................................................................................................................................308
Conguring the device to always compare Multi-Exit Discriminators..................................................................................................................309
Treating missing MEDs as the worst MEDs....................................................................................................................................................................310
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Conguring route reection parameters........................................................................................................................................................................... 310
Conguring confederations.................................................................................................................................................................................................... 312
Aggregating routes advertised to BGP4 neighbors.....................................................................................................................................................315
Conguring BGP4 restart.................................................................................................................................................................................................................316
Conguring BGP4 Restart for the global routing instance....................................................................................................................................... 316
Conguring BGP4 Restart for a VRF................................................................................................................................................................................316
Conguring timers for BGP4 Restart (optional).............................................................................................................................................................316
BGP4 null0 routing....................................................................................................................................................................................................................317
Conguring BGP4 null0 routing..........................................................................................................................................................................................318
Modifying redistribution parameters............................................................................................................................................................................................321
Redistributing connected routes...........................................................................................................................................................................................321
Redistributing RIP routes.........................................................................................................................................................................................................322
Redistributing OSPF external routes..................................................................................................................................................................................322
Redistributing static routes......................................................................................................................................................................................................323
Redistributing IBGP routes.....................................................................................................................................................................................................323
Filtering.....................................................................................................................................................................................................................................................323
AS-path ltering..........................................................................................................................................................................................................................323
BGP4 ltering communities.................................................................................................................................................................................................. 326
Dening and applying IP prex lists....................................................................................................................................................................................327
Dening neighbor distribute lists..........................................................................................................................................................................................328
Dening route maps..................................................................................................................................................................................................................329
Using a table map to set the tag value...............................................................................................................................................................................336
Conguring cooperative BGP4 route ltering................................................................................................................................................................337
Four-byte Autonomous System Numbers (AS4).................................................................................................................................................................. 339
Enabling AS4 numbers............................................................................................................................................................................................................340
BGP4 AS4 attribute errors.............................................................................................................................................................................................................. 344
Error logs........................................................................................................................................................................................................................................344
Conguring route ap dampening................................................................................................................................................................................................344
Globally conguring route ap dampening......................................................................................................................................................................345
Using a route map to congure route ap dampening for a specic neighbor................................................................................................346
Removing route dampening from a route........................................................................................................................................................................347
Displaying and clearing route ap dampening statistics............................................................................................................................................347
Generating traps for BGP4..............................................................................................................................................................................................................348
Conguring BGP4...............................................................................................................................................................................................................................349
Entering and exiting the address family conguration level...............................................................................................................................................350
BGP route reector.............................................................................................................................................................................................................................350
Conguring BGP route reector...........................................................................................................................................................................................351
Specifying a maximum AS path length......................................................................................................................................................................................353
Setting a global maximum AS path limit.......................................................................................................................................................................... 354
Setting a maximum AS path limit for a peer group or neighbor.............................................................................................................................354
BGP4 max-as error messages......................................................................................................................................................................................................355
Maximum AS path limit error.................................................................................................................................................................................................355
Memory limit error......................................................................................................................................................................................................................355
Originating the default route............................................................................................................................................................................................................355
Changing the default metric used for route cost.....................................................................................................................................................................355
Conguring a static BGP4 network ............................................................................................................................................................................................ 356
Setting an administrative distance for a static BGP4 network.................................................................................................................................356
Limiting advertisement of a static BGP4 network to selected neighbors.......................................................................................................... 357
Dynamic route lter update....................................................................................................................................................................................................357
Generalized TTL Security Mechanism support...................................................................................................................................................................... 359
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Displaying BGP4 information.........................................................................................................................................................................................................359
Displaying summary BGP4 information.......................................................................................................................................................................... 359
Displaying the active BGP4 conguration.......................................................................................................................................................................362
Displaying summary neighbor information.....................................................................................................................................................................362
Displaying BGP4 neighbor information............................................................................................................................................................................364
Displaying peer group information......................................................................................................................................................................................372
Displaying summary route information.............................................................................................................................................................................372
Displaying VRF instance information.................................................................................................................................................................................373
Displaying the BGP4 route table.........................................................................................................................................................................................373
Displaying BGP4 route-attribute entries..........................................................................................................................................................................380
Displaying the routes BGP4 has placed in the IP route table..................................................................................................................................381
Displaying route ap dampening statistics...................................................................................................................................................................... 381
Displaying the active route map conguration...............................................................................................................................................................382
Displaying BGP4 graceful restart neighbor information............................................................................................................................................383
Displaying AS4 details............................................................................................................................................................................................................. 383
Updating route information and resetting a neighbor session.................................................................................................................................390
Using soft reconguration.......................................................................................................................................................................................................390
Dynamically requesting a route refresh from a BGP4 neighbor............................................................................................................................392
Closing or resetting a neighbor session............................................................................................................................................................................394
Clearing and resetting BGP4 routes in the IP route table..........................................................................................................................................395
Clearing trac counters.....................................................................................................................................................................................................................395
Clearing diagnostic buers.............................................................................................................................................................................................................. 396
BGP4+..............................................................................................................................................................................................................................397
BGP4+ overview..................................................................................................................................................................................................................................397
BGP global mode ...............................................................................................................................................................................................................................397
IPv6 unicast address family.............................................................................................................................................................................................................398
BGP4+ neighbors................................................................................................................................................................................................................................399
BGP4+ peer groups............................................................................................................................................................................................................................399
BGP4+ next hop recursion.............................................................................................................................................................................................................. 400
BGP4+ NLRIs and next hop attributes.......................................................................................................................................................................................400
BGP4+ route reection......................................................................................................................................................................................................................401
BGP4+ route aggregation................................................................................................................................................................................................................401
BGP4+ multipath................................................................................................................................................................................................................................. 401
Route maps............................................................................................................................................................................................................................................402
BGP4+ outbound route ltering.................................................................................................................................................................................................... 402
BGP4+ confederations......................................................................................................................................................................................................................402
BGP4+ extended community.........................................................................................................................................................................................................403
BGP4+ graceful restart......................................................................................................................................................................................................................403
Conguring BGP4+............................................................................................................................................................................................................................ 403
Conguring BGP4+ neighbors using global IPv6 addresses..................................................................................................................................404
Conguring BGP4+ neighbors using link-local addresses.......................................................................................................................................404
Conguring BGP4+ peer groups.........................................................................................................................................................................................405
Conguring a peer group with IPv4 and IPv6 peers...................................................................................................................................................406
Importing routes into BGP4+................................................................................................................................................................................................407
Advertising the default BGP4+ route.................................................................................................................................................................................408
Advertising the default BGP4+ route to a specic neighbor....................................................................................................................................408
Using the IPv6 default route as a valid next hop for a BGP4+ route....................................................................................................................409
Enabling next-hop recursion..................................................................................................................................................................................................409
Conguring a cluster ID for a route reector...................................................................................................................................................................410
Conguring a route reector client.......................................................................................................................................................................................410
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Aggregating routes advertised to BGP neighbors........................................................................................................................................................411
Enabling load-balancing across dierent paths.............................................................................................................................................................411
Conguring a route map for BGP4+ prexes.................................................................................................................................................................412
Redistributing prexes into BGP4+.....................................................................................................................................................................................413
Conguring BGP4+ outbound route ltering..................................................................................................................................................................414
Conguring BGP4+ confederations................................................................................................................................................................................... 415
Dening a community ACL....................................................................................................................................................................................................415
Applying a BGP extended community lter....................................................................................................................................................................416
Disabling BGP4+ graceful restart........................................................................................................................................................................................417
Re-enabling BGP4+ graceful restart..................................................................................................................................................................................418
Disabling the BGP AS_PATH check function................................................................................................................................................................ 420
Displaying BGP4+ statistics...................................................................................................................................................................................................420
Displaying BGP4+ neighbor statistics...............................................................................................................................................................................423
Clearing BGP4+ dampened paths......................................................................................................................................................................................425
VRRPv2........................................................................................................................................................................................................................... 427
VRRPv2 overview................................................................................................................................................................................................................................427
VRRP terminology..................................................................................................................................................................................................................... 429
VRRP hold timer.........................................................................................................................................................................................................................430
VRRP interval timers.................................................................................................................................................................................................................430
VRRP authentication.................................................................................................................................................................................................................431
VRRP master device abdication to backup device.......................................................................................................................................................432
ARP and VRRP control packets...........................................................................................................................................................................................432
Enabling an owner VRRP device...................................................................................................................................................................................................432
Enabling a backup VRRP device...................................................................................................................................................................................................434
Conguring simple text authentication on VRRP interfaces..............................................................................................................................................435
Conguring MD5 authentication on VRRP interfaces......................................................................................................................................................... 436
Abdicating VRRP master device status......................................................................................................................................................................................437
Tracked ports and track priority with VRRP and VRRP-E..................................................................................................................................................439
Tracking ports and setting the VRRP priority..................................................................................................................................................................439
VRRP backup preemption...............................................................................................................................................................................................................440
Disabling VRRP backup preemption................................................................................................................................................................................. 440
Accept mode for backup VRRP devices....................................................................................................................................................................................441
Enabling accept mode on a backup VRRP device.......................................................................................................................................................441
Suppressing RIP route advertisements on VRRP backup devices................................................................................................................................ 443
VRRP-Ev2 overview...........................................................................................................................................................................................................................443
Enabling a VRRP-E device..............................................................................................................................................................................................................444
VRRP-E load-balancing using short-path forwarding.........................................................................................................................................................445
Packet routing with short-path forwarding to balance trac load..........................................................................................................................445
Short-path forwarding with revert priority.........................................................................................................................................................................446
Conguring VRRP-E load-balancing using short-path forwarding...................................................................................................................... 447
VRRP-E slow start timer...................................................................................................................................................................................................................448
Conguring a VRRP-E slow-start timer............................................................................................................................................................................448
Conguration example: ISSU upgrade using VRRP-E........................................................................................................................................................449
Displaying VRRPv2 information................................................................................................................................................................................................... 450
Clearing VRRPv2 statistics..............................................................................................................................................................................................................451
VRRPv3........................................................................................................................................................................................................................... 453
VRRPv3 overview................................................................................................................................................................................................................................453
Enabling an IPv6 VRRPv3 owner device..................................................................................................................................................................................454
Enabling an IPv6 VRRPv3 backup device................................................................................................................................................................................455
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Enabling an IPv4 VRRPv3 owner device..................................................................................................................................................................................456
Enabling an IPv4 VRRPv3 backup device................................................................................................................................................................................457
Tracked ports and track priority with VRRP and VRRP-E..................................................................................................................................................458
Tracking ports and setting VRRP priority using VRRPv3......................................................................................................................................... 459
Accept mode for backup VRRP devices....................................................................................................................................................................................459
Enabling accept mode on a backup VRRP device.......................................................................................................................................................460
Alternate VRRPv2 checksum for VRRPv3 IPv4 sessions................................................................................................................................................ 461
Enabling the VRRPv2 checksum computation method in a VRRPv3 IPv4 session....................................................................................461
Displaying alternate VRRPv2 checksum settings........................................................................................................................................................ 462
Automatic generation of a virtual link-local address for VRRPv3...................................................................................................................................463
Assigning an auto-generated link-local IPv6 address for a VRRPv3 cluster................................................................................................... 464
Displaying VRRPv3 statistics......................................................................................................................................................................................................... 465
Clearing VRRPv3 statistics..............................................................................................................................................................................................................466
VRRP-Ev3 Overview......................................................................................................................................................................................................................... 466
Enabling an IPv6 VRRP-Ev3 device...........................................................................................................................................................................................467
Displaying and clearing VRRP-Ev3 statistics.......................................................................................................................................................................... 468
Multi-VRF........................................................................................................................................................................................................................471
Multi-VRF overview............................................................................................................................................................................................................................ 471
FastIron considerations for Multi-VRF...............................................................................................................................................................................473
VRF-related system-max values.........................................................................................................................................................................................473
Additional features to support Multi-VRF........................................................................................................................................................................ 475
Conguring Multi-VRF...................................................................................................................................................................................................................... 476
Conguring VRF system-max values ...............................................................................................................................................................................476
Creating VLANs as links on a tagged port for security...............................................................................................................................................478
Conguring a VRF instance...................................................................................................................................................................................................478
Starting a routing process for a VRF..................................................................................................................................................................................479
Assigning a Layer 3 interface to a VRF.............................................................................................................................................................................480
Assigning a loopback interface to a VRF..........................................................................................................................................................................480
Verifying a Multi-VRF conguration................................................................................................................................................................................... 481
Removing a VRF conguration............................................................................................................................................................................................482
Conguring static ARP for Multi-VRF............................................................................................................................................................................... 482
Conguring additional ARP features for Multi-VRF.....................................................................................................................................................483
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Brocade FastIron Layer 3 Routing Conguration Guide
Copyright Statement
©
2016, Brocade Communications Systems, Inc. All Rights Reserved.
Brocade, Brocade Assurance, the B-wing symbol, ClearLink, DCX, Fabric OS, HyperEdge, ICX, MLX, MyBrocade, OpenScript, VCS, VDX, Vplane, and Vyatta are registered trademarks, and Fabric Vision is a trademark of Brocade Communications Systems, Inc., in the United States and/or in other countries. Other brands, products, or service names mentioned may be trademarks of others.
Notice: This document is for informational purposes only and does not set forth any warranty, expressed or implied, concerning any equipment, equipment feature, or service oered or to be oered by Brocade. Brocade reserves the right to make changes to this document at any time, without notice, and assumes no responsibility for its use. This informational document describes features that may not be currently available. Contact a Brocade sales oce for information on feature and product availability. Export of technical data contained in this document may require an export license from the United States government.
The authors and Brocade Communications Systems, Inc. assume no liability or responsibility to any person or entity with respect to the accuracy of this document or any loss, cost, liability, or damages arising from the information contained herein or the computer programs that accompany it.
The product described by this document may contain open source software covered by the GNU General Public License or other open source license agreements. To nd out which open source software is included in Brocade products, view the licensing terms applicable to the open source software, and obtain a copy of the programming source code, please visit http://www.brocade.com/support/oscd.
Brocade FastIron Layer 3 Routing Conguration Guide 53-1003903-04 15
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Preface

• Document conventions...................................................................................................................................................................................17
• Brocade resources............................................................................................................................................................................................ 18
• Contacting Brocade Technical Support....................................................................................................................................................19
• Document feedback.........................................................................................................................................................................................19

Document conventions

The document conventions describe text formatting conventions, command syntax conventions, and important notice formats used in Brocade technical documentation.

Text formatting conventions

Text formatting conventions such as boldface, italic, or Courier font may be used in the ow of the text to highlight specic words or phrases.
Format Description bold text Identies command names
Identies keywords and operands
Identies the names of user-manipulated GUI elements
Identies text to enter at the GUI
italic text Identies emphasis
Identies variables
Identies document titles
Courier font
Identies CLI output
Identies command syntax examples

Command syntax conventions

Bold and italic text identify command syntax components. Delimiters and operators dene groupings of parameters and their logical relationships.
Convention Description bold text Identies command names, keywords, and command options.
italic text Identies a variable.
value In Fibre Channel products, a xed value provided as input to a command option is printed in plain text, for
example, --show WWN.
[ ] Syntax components displayed within square brackets are optional.
Default responses to system prompts are enclosed in square brackets.
{ x | y | z } A choice of required parameters is enclosed in curly brackets separated by vertical bars. You must select
one of the options.
In Fibre Channel products, square brackets may be used instead for this purpose.
x | y A vertical bar separates mutually exclusive elements.
Brocade FastIron Layer 3 Routing Conguration Guide 53-1003903-04 17

Brocade resources

Convention Description
< > Nonprinting characters, for example, passwords, are enclosed in angle brackets.
... Repeat the previous element, for example, member[member...].
\ Indicates a “soft” line break in command examples. If a backslash separates two lines of a command
input, enter the entire command at the prompt without the backslash.

Notes, cautions, and warnings

Notes, cautions, and warning statements may be used in this document. They are listed in the order of increasing severity of potential hazards.
NOTE
A Note provides a tip, guidance, or advice, emphasizes important information, or provides a reference to related information.
ATTENTION
An Attention statement indicates a stronger note, for example, to alert you when trac might be interrupted or the device might
reboot.
CAUTION
A Caution statement alerts you to situations that can be potentially hazardous to you or cause damage to hardware,
rmware, software, or data.
DANGER
A Danger statement indicates conditions or situations that can be potentially lethal or extremely hazardous to you. Safety
labels are also attached directly to products to warn of these conditions or situations.
Brocade resources
Visit the Brocade website to locate related documentation for your product and additional Brocade resources.
You can download additional publications supporting your product at www.brocade.com. Select the Brocade Products tab to locate your product, then click the Brocade product name or image to open the individual product page. The user manuals are available in the resources module at the bottom of the page under the Documentation category.
To get up-to-the-minute information on Brocade products and resources, go to MyBrocade. You can register at no cost to obtain a user ID and password.
Release notes are available on MyBrocade under Product Downloads.
White papers, online demonstrations, and data sheets are available through the Brocade website.
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Brocade FastIron Layer 3 Routing Conguration Guide

Document feedback

Contacting Brocade Technical Support

As a Brocade customer, you can contact Brocade Technical Support 24x7 online, by telephone, or by e-mail. Brocade OEM customers contact their OEM/Solutions provider.

Brocade customers

For product support information and the latest information on contacting the Technical Assistance Center, go to http://www.brocade.com/
services-support/index.html.
If you have purchased Brocade product support directly from Brocade, use one of the following methods to contact the Brocade Technical Assistance Center 24x7.
Online Telephone E-mail
Preferred method of contact for non-urgent issues:
• My Cases through MyBrocade
• Software downloads and licensing tools
• Knowledge Base
Required for Sev 1-Critical and Sev 2-High issues:
• Continental US: 1-800-752-8061
• Europe, Middle East, Africa, and Asia Pacic: +800-AT FIBREE (+800 28 34 27 33)
• For areas unable to access toll free number: +1-408-333-6061
• Toll-free numbers are available in many countries.
support@brocade.com
Please include:
• Problem summary
• Serial number
• Installation details
• Environment description

Brocade OEM customers

If you have purchased Brocade product support from a Brocade OEM/Solution Provider, contact your OEM/Solution Provider for all of your product support needs.
• OEM/Solution Providers are trained and
• Brocade provides backline support for issues that cannot be resolved by the OEM/Solution Provider.
• Brocade Supplemental Support augments your existing OEM support contract, providing direct access to Brocade expertise. For more information, contact Brocade or your OEM.
• For questions regarding service levels and response times, contact your OEM/Solution Provider.
certied by Brocade to support Brocade® products.
Document feedback
To send feedback and report errors in the documentation you can use the feedback form posted with the document or you can e-mail the documentation team.
Quality is our rst concern at Brocade and we have made every eort to ensure the accuracy and completeness of this document. However, if you nd an error or an omission, or you think that a topic needs further development, we want to hear from you. You can provide feedback in two ways:
• Through the online feedback form in the HTML documents posted on www.brocade.com.
• By sending your feedback to documentation@brocade.com.
Provide the publication title, part number, and as much detail as possible, including the topic heading and page number if applicable, as well as your suggestions for improvement.
Brocade FastIron Layer 3 Routing Conguration Guide 53-1003903-04 19
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About This Document

• Supported hardware and software..............................................................................................................................................................21
• What’s new in this document........................................................................................................................................................................21
• How command information is presented in this guide......................................................................................................................22

Supported hardware and software

This guide supports the following product families for FastIron release 8.0.40:
• Brocade ICX 7250 Series (ICX 7250)
• Brocade ICX 7450 Series (ICX 7450)
• Brocade ICX 7750 Series (ICX 7750)
For information about the product family.
specic models and modules supported in a product family, refer to the hardware installation guide for that

What’s new in this document

The following tables describe information added or
TABLE 1 Summary of enhancements in FastIron release 8.0.40a
Feature Description Location
Updated content for defect x. Removed unsupported sections.
TABLE 2 Summary of enhancements in FastIron release 8.0.40
Feature Description Location
DHCP auto-provisioning DHCP auto-provisioning allows you to
DHCP client link layer option You can now specify the client link layer option in
DHCP options DHCP server options 176, 242, and 252 have
User-congurable MAC address per IP interface
Information taxonomy applied To improve consistency and access, this guide has
modied in this guide for FastIron software releases 8.0.40 and 8.0.40a.
The chapter BGP4 has been updated as part of a defect x.
automatically deploy devices with management IP addresses and le upgrades.
the DHCP relay-option messages.
been introduced.
Manual conguration of an IP MAC address for each Layer 3 physical or virtual ethernet (VE) interface on a device is permitted. The congured MAC address is used by routing protocols or hardware communications related to IPv4 or IPv6 addresses on the interface.
been restructured according to approved Brocade information taxonomy.
BGP4
"DHCP auto-provisioning" in the Brocade FastIron DHCP Conguration Guide.
"DHCP relay include options" in the Brocade FastIron DHCP Conguration Guide.
"Conguring WPAD" in the Brocade FastIron DHCP Conguration Guide.
"Conguring Avaya IP telephony" in the Brocade FastIron DHCP Conguration Guide.
User-congurable MAC address per IP interface
on page 102
These changes occur throughout the text.
Brocade FastIron Layer 3 Routing Conguration Guide 53-1003903-04 21

How command information is presented in this guide

How command information is presented in this guide
For all new content supported in FastIron Release 8.0.20 and later, command information is documented in a standalone command reference guide.
To provide consistent CLI documentation for all products, there is now a standalone command reference for the FastIron platforms.
In the Brocade FastIron Command Reference, the command pages are in alphabetical order and follow a standard format to present syntax, parameters, mode, usage guidelines, examples, and command history.
NOTE
Many commands from previous FastIron releases are also included in the command reference.
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Brocade FastIron Layer 3 Routing Conguration Guide

ARP - Address Resolution Protocol

• ARP parameter conguration.......................................................................................................................................................................23
• Displaying the ARP table ...............................................................................................................................................................................29
• Reverse Address Resolution Protocol conguration...........................................................................................................................29
• Dynamic ARP inspection ..............................................................................................................................................................................31
ARP parameter conguration
Address Resolution Protocol (ARP) is a standard IP protocol that enables an IP Layer 3 switch to obtain the MAC address of another device interface when the Layer 3 switch knows the IP address of the interface. ARP is enabled by default and cannot be disabled.
NOTE
Brocade Layer 2 switches also support ARP. However, the conguration options described later in this section apply only to Layer 3 switches, not to Layer 2 switches.

How ARP works

A Layer 3 switch needs to know a destination MAC address when forwarding trac, because the Layer 3 switch encapsulates the IP packet in a Layer 2 packet (MAC layer packet) and sends the Layer 2 packet to a MAC interface on a device directly attached to the Layer 3 switch. The device can be the packet nal destination or the next-hop router toward the destination.
The Layer 3 switch encapsulates IP packets in Layer 2 packets regardless of whether the ultimate destination is locally attached or is multiple router hops away. Because the Layer 3 switch IP route table and IP forwarding cache contain IP address information but not MAC address information, the Layer 3 switch cannot forward IP packets based solely on the information in the route table or forwarding cache. The Layer 3 switch needs to know the MAC address that corresponds with the IP address of either the packet locally attached destination or the next-hop router that leads to the destination.
For example, to forward a packet whose destination is multiple router hops away, the Layer 3 switch must send the packet to the next­hop router toward its destination, or to a default route or default network route if the IP route table does not contain a route to the packet destination. In each case, the Layer 3 switch must encapsulate the packet and address it to the MAC address of a locally attached device, the next-hop router toward the IP packet destination.
To obtain the MAC address required for forwarding a datagram, the Layer 3 switch rst looks in the ARP cache (not the static ARP table) for an entry that lists the MAC address for the IP address. The ARP cache maps IP addresses to MAC addresses. The cache also lists the port attached to the device and, if the entry is dynamic, the age of the entry. A dynamic ARP entry enters the cache when the Layer 3 switch receives an ARP reply or receives an ARP request (which contains the sender IP address and MAC address). A static entry enters the ARP cache from the separate static ARP table when the interface for the entry comes up.
To ensure the accuracy of the ARP cache, each dynamic entry has its own age timer. The timer is reset to zero each time the Layer 3 switch receives an ARP reply or ARP request containing the IP address and MAC address of the entry. If a dynamic entry reaches its maximum allowable age, the entry times out and the software removes the entry from the table. Static entries do not age out and can be removed only by you.
If the ARP cache does not contain an entry for the destination IP address, the Layer 3 switch broadcasts an ARP request out all its IP interfaces. The ARP request contains the IP address of the destination. If the device with the IP address is directly attached to the Layer 3 switch, the device sends an ARP response containing its MAC address. The response is a unicast packet addressed directly to the Layer 3 switch. The Layer 3 switch places the information from the ARP response into the ARP cache.
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ARP parameter conguration
ARP requests contain the IP address and MAC address of the sender, so all devices that receive the request learn the MAC address and IP address of the sender and can update their own ARP caches accordingly.
NOTE
The ARP request broadcast is a MAC broadcast, which means the broadcast goes only to devices that are directly attached to the Layer 3 switch. A MAC broadcast is not routed to other networks. However, some routers, including Brocade Layer 3 switches, can be congured to reply to ARP requests from one network on behalf of devices on another network.
NOTE
If the router receives an ARP request packet that it is unable to deliver to the nal destination because of the ARP timeout and no ARP response is received (the Layer 3 switch knows of no route to the destination address), the router sends an ICMP Host Unreachable message to the source.
FIGURE 1 ARP supplies the MAC address corresponding to an IP address
If Device A wants to communicate with Device B, knowing the IP address of Device B is not sucient; the MAC address is also required. ARP supplies the MAC address.

Rate limiting ARP packets

You can limit the number of ARP packets the Brocade device accepts during each second. By default, the software does not limit the number of ARP packets the device can receive. Since the device sends ARP packets to the CPU for processing, if a device in a busy network receives a high number of ARP packets in a short period of time, some CPU processing might be deferred while the CPU processes the ARP packets.
To prevent the CPU from becoming will accept each second. When you congure an ARP rate limit, the device accepts up to the maximum number of packets you specify, but drops additional ARP packets received during the one-second interval. When a new one-second interval starts, the counter restarts at zero, so the device again accepts up to the maximum number of ARP packets you specied, but drops additional packets received within the interval.
24 53-1003903-04
ooded by ARP packets in a busy network, you can restrict the number of ARP packets the device
Brocade FastIron Layer 3 Routing Conguration Guide
ARP parameter conguration
To limit the number of ARP packets the device will accept each second, enter the rate-limit-arp command at the global CONFIG level of the CLI.
device(config)# rate-limit-arp 100
This command during a one-second interval, the device drops the additional ARP packets during the remainder of that one-second interval.
Syntax:[no] rate-limit-arp num
The num variable species the number of ARP packets and can be from 0 through 100. If you specify 0, the device will not accept any ARP packets.
congures the device to accept up to 100 ARP packets each second. If the device receives more than 100 ARP packets
NOTE
If you want to change a previously congured the ARP rate limiting policy, you must remove the previously congured policy using the no rate-limit-arp command before entering the new policy.

Changing the ARP aging period

When the Layer 3 switch places an entry in the ARP cache, the Layer 3 switch also starts an aging timer for the entry. The aging timer ensures that the ARP cache does not retain learned entries that are no longer valid. An entry can become invalid when the device with the MAC address of the entry is no longer on the network.
The ARP age change the ARP age to a value from 0 through 240 minutes. You cannot change the ARP age on Layer 2 switches. If you set the ARP age to zero, aging is disabled and entries do not age out.
aects dynamic (learned) entries only, not static entries. The default ARP age is ten minutes. On Layer 3 switches, you can
NOTE
Host devices connected to an ICX 7750 that also have a valid IP address and reply periodically to the arp request are not timed out, even if no trac is destined for the device. This behavior is restricted to only ICX 7750 devices.
To globally change the ARP aging parameter to 20 minutes, enter the ip arp-age command.
device(config)# ip arp-age 20
Syntax: [no] ip arp-age num
The num parameter species the number of minutes, which can be from 0 through 240. The default is 10. If you specify 0, aging is disabled.
To override the globally congured IP ARP age on an individual interface, enter the ip arp-age command followed by the new value at the interface conguration level.
device(config-if-e1000-1/1/1)# ip arp-age 30

Enabling proxy ARP

Proxy ARP allows a Layer 3 switch to answer ARP requests from devices on one network on behalf of devices in another network. Because ARP requests are MAC-layer broadcasts, they reach only the devices that are directly connected to the sender of the ARP request. Thus, ARP requests do not cross routers.
For example, if Proxy ARP is enabled on a Layer 3 switch connected to two subnets, 10.10.10.0/24 and 10.20.20.0/24, the Layer 3 switch can respond to an ARP request from 10.10.10.69 for the MAC address of the device with IP address 10.20.20.69. In standard ARP, a request from a device in the 10.10.10.0/24 subnet cannot reach a device in the 10.20.20.0 subnet if the subnets are on dierent network cables, and thus is not answered.
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ARP parameter conguration
NOTE
An ARP request from one subnet can reach another subnet when both subnets are on the same physical segment (Ethernet cable), because MAC-layer broadcasts reach all the devices on the segment.
Proxy ARP is disabled by default on Brocade Layer 3 switches. This feature is not supported on Brocade Layer 2 switches.
You can enable proxy ARP at the Interface level, as well as at the Global CONFIG level, of the CLI.
NOTE
Conguring proxy ARP at the Interface level overrides the global conguration.
Enabling proxy ARP globally
To enable IP proxy ARP on a global basis, enter the ip proxy-arp command.
device(config)# ip proxy-arp
To again disable IP proxy ARP on a global basis, enter the no ip proxy-arp command.
device(config)# no ip proxy-arp
Syntax: [no] ip proxy-arp
Enabling IP ARP on an interface
NOTE
Conguring proxy ARP at the Interface level overrides the global conguration.
To enable IP proxy ARP on an interface, enter the following commands.
device(config)# interface ethernet 5 device(config-if-e1000-5)# ip proxy-arp enable
To again disable IP proxy ARP on an interface, enter the following command.
device(config)# interface ethernet 5 device(config-if-e1000-5)# ip proxy-arp disable
Syntax: [no] ip proxy-arp { enable | disable }
NOTE
By default, gratuitous ARP is disabled for local proxy ARP.

Creating static ARP entries

Static ARP entries are added to the ARP cache when they are congured. Static ARP entries are useful in cases where you want to pre­congure an entry for a device that is not connected to the Layer 3 switch, or you want to prevent a particular entry from aging out.
Brocade Layer 3 switches have a static ARP table, in addition to the regular ARP cache. Unlike static ARP entries, dynamic ARP entries are removed from the ARP cache if the ARP aging interval expires before the entry is refreshed. Static entries do not age out, regardless of whether the Brocade device receives an ARP request from the device that has the entry address.
NOTE
You cannot create static ARP entries on a Layer 2 switch.
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Brocade FastIron Layer 3 Routing Conguration Guide
ARP parameter conguration
The maximum number of static ARP entries you can congure depends on the software version running on the device.
To create a static ARP entry, enter a command such as the following.
device(config)# arp 1 10.53.4.2 0000.0054.2348 ethernet 1/1/2
Syntax: arp num ip-addr mac-addr ethernet port
The num variable
species the entry number. You can specify a number from 1 up to the maximum number of static entries allowed on
the device.
The ip-addr variable species the IP address of the device that has the MAC address of the entry.
The mac-addr variable species the MAC address of the entry.
Changing the maximum number of entries the static ARP table can hold
NOTE
The basic procedure for changing the static ARP table size is the same as the procedure for changing other congurable cache or table sizes.
To increase the maximum number of static ARP table entries you can congure on a Brocade Layer 3 switch, enter commands such as the following at the global CONFIG level of the CLI.
device(config)# system-max ip-static-arp 1000 device(config)# write memory device(config)# end device# reload
NOTE
You must save the conguration to the startup-cong le and reload the software after changing the static ARP table size to place the change into eect.
Syntax: system-max ip-static-arp num
The num variable indicates the maximum number of static ARP entries and can be within one of these ranges, depending on the software version running on the device.
TABLE 3 Static ARP entry support
Device Default maximum Congurable minimum Congurable maximum
ICX 7250 512 512 6000
ICX 7450 512 512 6000
ICX 7750 512 512 6000
Enabling learning gratuitous ARP
Learning gratuitous ARP enables Brocade Layer 3 devices to learn ARP entries from incoming gratuitous ARP packets from the hosts which are directly connected. This help achieve faster convergence for the hosts when they are ready to send trac.
A new ARP entry is created when a gratuitous ARP packet is received. If the ARP is already existing, it will be updated with the new content.
To enable learning gratuitous ARP, enter the following command at the device conguration level.
Brocade (config)# ip arp learn-gratuitous-arp
Syntax: [no] ip arp learn-gratuitous-arp
The no form of the command disables learning gratuitous ARP from the device.
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ARP parameter conguration
Use the show run command to see whether ARP is enabled or disabled. Use the show arp command to see the newly learned ARP entries.
Use the clear arp command to clear learned ARP entries. Static ARP entries are not removed.

ARP Packet Validation

Validates ARP packets to avoid
To avoid trac interruption or loss, ARP Packet Validation allows the user to detect and drop ARP packets that do not pass the ARP validation process. ARP Packet Validation is disabled by default and can be enabled at the global conguration level. This functionality can be congured for the destination MAC address, the IP address and the source MAC address or with a combination of these parameters. The Ethernet header contains the destination MAC address and source MAC address, while the ARP packet contains the sender hardware address and target hardware address.
Follow these steps to perform checks on the incoming ARP packets.
1. Enter the global conguration mode.
2. Run the ip arp inspection validate [dst-mac | ip | src-mac] command to perform a check on any incoming ARP packets. Use one of the following parameters to run the validation check:
• dst-mac
The destination MAC address in the Ethernet header must be the same as the target hardware address in the ARP body. This validation is performed for the ARP response packet. When the destination MAC address validation is enabled, the packets with dierent MAC addresses are classied as invalid and are dropped.
• src-mac
The source MAC address in the Ethernet header and the sender hardware address in the ARP body must be the same. This validation is performed for the ARP request and response packets. When the source MAC validation is enabled, the packets with dierent MAC addresses are classied as invalid and are dropped.
• ip
Each ARP packet has a sender IP address and target IP address. The target IP address cannot be invalid or an unexpected IP address in the ARP response packet. The sender IP address cannot be an invalid or an unexpected IP address in the ARP request and response packets. Addresses include 0.0.0.0, 255.255.255.255, and all IP multicast addresses. When the IP address validation is enabled, the packets with invalid and unexpected IP addresses are classied as invalid and are dropped.
trac interruption or loss.
The following example shows ARP packets being validated for the destination MAC address.
device(config)# configuration terminal device(config)#ip arp inspection validate dst-mac

Ingress ARP packet priority

You can volume. Ingress ARP packets have a default priority value of 4. At the default priority value, ingress ARP packets may get dropped because of high trac volume or non-ARP packets with higher priority values. This can cause devices to become unreachable. If the ingress ARP packets have higher priority values than the default priority value, a high volume of ARP trac may lead to drops in control trac. This may cause trac loops in the network.
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congure the priority of the ingress ARP packets to an optimum value that depends on your network conguration and trac
NOTE
You cannot change the priority of the ingress ARP packets on the management port.
Brocade FastIron Layer 3 Routing Conguration Guide
Reverse Address Resolution Protocol conguration
Conguring the priority of ingress ARP packets
To congure the priority of ingress ARP packets, use the arp-internal-priority priority-value command in global conguration mode.
The following example shows the priority of ingress ARP packets set to level 7.
Brocade(config)# arp-internal-priority 7

Displaying the ARP table

To display the ARP table, enter the show arp command.
device# show arp Total number of ARP entries: 2 Entries in default routing instance: No. IP Address MAC Address Type Age Port Status 1 10.1.1.100 0000.0000.0100 Dynamic 0 1/1/1*2/1/25 Valid 2 10.37.69.129 02e0.5215.cae3 Dynamic 0 mgmt1 Valid
The command displays all ARP entries in the system.
Syntax: show arp
Reverse Address Resolution Protocol conguration
The Reverse Address Resolution Protocol (RARP) provides a simple mechanism for directly-attached IP hosts to boot over the network. RARP allows an IP host that does not have a means of storing its IP address across power cycles or software reloads to query a directly­attached router for an IP address.
RARP is enabled by default. However, you must create a RARP entry for each host that will use the Layer 3 switch for booting. A RARP entry consists of the following information:
• The entry number - The entry sequence number in the RARP table.
• The MAC address of the boot client.
• The IP address you want the Layer 3 switch to give to the client.
When a client sends a RARP broadcast requesting an IP address, the Layer 3 switch responds to the request by looking in the RARP table for an entry that contains the client MAC address:
• If the RARP table contains an entry for the client, the Layer 3 switch sends a unicast response to the client that contains the IP address associated with the client MAC address in the RARP table.
• If the RARP table does not contain an entry for the client, the Layer 3 switch silently discards the RARP request and does not reply to the client.
How RARP Diers from BootP and DHCP
RARP, BootP, and DHCP are dierent methods for providing IP addresses to IP hosts when they boot. These methods dier in the following ways:
• Location of congured host addresses
– RARP requires static conguration of the host IP addresses on the Layer 3 device. The Layer 3 device replies directly to a
host request by sending an IP address you have congured in the RARP table.
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Reverse Address Resolution Protocol conguration
– The Layer 3 device forwards BootP and DHCP requests to a third-party BootP/DHCP server that contains the IP
addresses and other host conguration information.
• Connection of host to boot source (Layer 3 device or BootP/DHCP server)
– RARP requires the IP host to be directly attached to the Layer 3 device. – An IP host and the BootP/DHCP server can be on dierent networks and on dierent routers as long as the routers are
congured to forward ("help") the host boot request to the boot server.
– You can centrally congure other host parameters on the BootP/DHCP server and supply those parameters to the host
along with its IP address.
To congure the Layer 3 device to forward BootP/DHCP requests when boot clients and boot servers are on dierent subnets on dierent Layer 3 device interfaces, refer to the DHCP client section in the Brocade FastIron Conguration Guide.

Disabling RARP

RARP is enabled by default. To disable RARP, enter the following command at the global CONFIG level.
device(config)# no ip rarp
Syntax: [no] ip rarp
To re-enable RARP, enter the following command.
device(config)# ip rarp

Creating static RARP entries

You must congure the RARP entries for the RARP table. The Layer 3 switch can send an IP address in reply to a client RARP request only if create a RARP entry for that client.
To assign a static IP RARP entry for static routes on a Brocade router, enter a command such as the following.
device(config)# rarp 1 0000.0054.2348 10.53.4.2
This command creates a RARP entry for a client with MAC address 0000.0054.2348. When the Layer 3 switch receives a RARP request from this client, the Layer 3 switch replies to the request by sending IP address 192.53.4.2 to the client.
Syntax: rap number mac-addr ip-addr
The number parameter identies the RARP entry number. You can specify an unused number from 1 to the maximum number of RARP entries supported on the device. To determine the maximum number of entries supported on the device, refer to the section "Displaying and modifying system parameter default settings" in the Brocade FastIron Platform and Layer 2 Switching Conguration Guide.
The mac-addr parameter species the MAC address of the RARP client.
The ip-addr parameter species the IP address the Layer 3 switch will give the client in response to the client RARP request.

Changing the maximum number of static RARP entries supported

The number of RARP entries the Layer 3 switch supports depends on how much memory the Layer 3 switch has. To determine how many RARP entries your Layer 3 switch can have, display the system default information using the procedure in the section "Displaying system parameter default values" in the Brocade FastIron Platform and Layer 2 Switching
Conguration Guide.
If your Layer 3 switch allows you to increase the maximum number of RARP entries, you can use a procedure in the same section to do so.
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Brocade FastIron Layer 3 Routing Conguration Guide
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