This article provides an example of dynamic ARP learning for an IRB interface over an ICL link.
When MC-LAG Active-Active is used, dynamic ARP learning does not happen over an ICL link.
Starting with Junos OS 15.1R3, dynamic ARP learning over ICL for IRB interfaces will happen when VRRP is configured without static ARP configuration. In the ARP table, ARP entries are shown as “ permanent remote ”. This eliminates configuring static ARP for all IRB interfaces in an MC-LAG Active-Active scenario. Lab output : EX9200:
ICCP +-----------------+ ge-0/1/3 ge-0/1/3 +----------------+ | +------------------------------+ | | EX9200 | | EX9200 | | SW-1 | | SW-2 | | +------------------------------+ | +-----------------+ ge-0/1/4 ICL ge-0/1/4 +----------------+ root@EX9200-SW1# show interfaces irb.10 family inet { address 10.10.10.1/24 { vrrp-group 10 { virtual-address 10.10.10.50; priority 150; } } } root@EX9200-SW2# show interfaces irb.10 family inet { address 10.10.10.2/24 { vrrp-group 10 { virtual-address 10.10.10.50; } } } root@EX9200-SW1# run show arp no-resolve MAC Address Address Interface Flags d8:b1:22:93:9d:70 10.10.10.2 irb.10 [ge-0/1/4.0] permanent remote 00:00:5e:00:01:0a 10.10.10.50 irb.10 permanent published d8:b1:22:93:9d:70 10.10.100.2 irb.100 [ge-0/1/3.0] none 00:00:5e:00:01:14 10.219.41.65 fxp0.0 none d8:b1:22:93:9d:70 20.20.20.2 irb.20 [ge-0/1/4.0] permanent remote 00:00:5e:00:01:14 20.20.20.50 irb.20 permanent published root@EX9200-SW2# run show arp no-resolve MAC Address Address Interface Flags d8:b1:22:93:95:70 10.10.10.1 irb.10 [ge-0/1/4.0] permanent remote 00:00:5e:00:01:0a 10.10.10.50 irb.10 permanent published d8:b1:22:93:95:70 10.10.100.1 irb.100 [ge-0/1/3.0] none 00:00:5e:00:01:14 10.219.41.65 fxp0.0 none d8:b1:22:93:95:70 20.20.20.1 irb.20 [ge-0/1/4.0] permanent remote 00:00:5e:00:01:14 20.20.20.50 irb.20 permanent published 02:00:00:00:00:10 128.0.0.16 em0.0 none 02:00:00:00:00:11 128.0.0.17 em0.0 none 02:00:00:00:00:12 128.0.0.18 em0.0 none
+-------------+ +------------+ | QFX5100 | [ICCP/ICL] |QFX5100 | | SW-1 +------------------------------+SW-2 | | | xe-0/0/1 xe-1/0/1 | | +-------------+ +------------+ root@SW-1> show version fpc0: -------------------------------------------------------------------------- Hostname: SW-1 Model: qfx5100-48t-6q Junos: 15.1R3.6 JUNOS Base OS boot [15.1R3.6] JUNOS Base OS Software Suite [15.1R3.6] JUNOS Crypto Software Suite [15.1R3.6] JUNOS Online Documentation [15.1R3.6] JUNOS Kernel Software Suite [15.1R3.6] JUNOS Packet Forwarding Engine Support (qfx-ex-x86-32) [15.1R3.6] JUNOS Routing Software Suite [15.1R3.6] JUNOS Enterprise Software Suite [15.1R3.6] JUNOS py-base-i386 [15.1R3.6] JUNOS Host Software [14.1X53-D35.3] root@SW-1# show interfaces irb.10 family inet { address 10.10.10.1/24 { vrrp-group 10 { virtual-address 10.10.10.50; priority 150; accept-data; } } } {master:0}[edit] root@SW-1# show interfaces irb.20 family inet { address 20.20.20.1/24 { vrrp-group 20 { virtual-address 20.20.20.50; accept-data; } } } root@SW-2# show interfaces irb.10 family inet { address 10.10.10.2/24 { vrrp-group 10 { virtual-address 10.10.10.50; accept-data; } } } {master:1}[edit] root@SW-2# show interfaces irb.20 family inet { address 20.20.20.2/24 { vrrp-group 20 { virtual-address 20.20.20.50; priority 110; } } } root@SW-1# run show interfaces mc-ae Member Link : ae2 Current State Machine's State: mcae active state Local Status : active Local State : up Peer Status : active Peer State : up Logical Interface : ae2.0 Topology Type : bridge Local State : up Peer State : up Peer Ip/MCP/State : 1.1.1.2 xe-0/0/1.0 up {master:0}[edit] root@SW-1# run show arp no-resolve MAC Address Address Interface Flags 44:aa:50:25:3d:80 10.10.10.2 irb.10 [xe-0/0/1.0] permanent 44:aa:50:25:3d:80 10.10.100.2 irb.100 [xe-0/0/1.0] permanent published 00:00:5e:00:01:15 10.219.42.193 em0.0 none 0c:86:10:99:d5:2c 10.219.42.194 em0.0 none 44:aa:50:25:3d:80 20.20.20.2 irb.20 [xe-0/0/1.0] permanent 20:4e:71:a6:7e:e5 30.0.0.1 xe-0/0/3.0 none 44:aa:50:25:29:83 192.168.1.1 em2.32768 none Total entries: 7