8/20/2018

Arista EOS 4.21 : L2 subinterface

Topology:

[rtr3]
  |
  | et2
  |    eth1.1
[rtr1]==============[rtr2]
  |    eth1.2
  | eth3
  |
[rtr4]

Configuration

interface et1.100
  encap dot1q vlan 100
  vlan id 1000
interface et1.200
  encap dot1q vlan 200
  vlan id 1000
interface eth2
  switch access vlan 1000
interface eth3
  switch mode trunk

L2 bridge domain
  • Above configuration is to create a L2 bridge domain of 4 end points - et1.100, et1.200, eth2 (access), eth3 (trunk). 
  • 1 bcast from et1.100, will be flood to et1.200, et2, et3
  • Vlan mapping is different, which is 1:1 relation. So no vlan 1000 on both et1.100 and et1.200
  • et1 must be "no switch". 
  • Feature is supported from 4.21.*?

2 comments:

  1. Hi, nice info. I did not find this is the docs, what exactly does it do?

    encap dot1q vlan 200
    vlan id 1000

    It expects packets to have .1q tag 200 yet it is in bridge domain 1000? Is 200 being translated to 1000 on these subinerfaces?

    ReplyDelete
  2. Nevermind, I "labbed" it up.

    ReplyDelete