Posted on March 31, 2021 10:37 am
 |  Asked by Devriza Imanta
Print Friendly, PDF & Email

Does Arista support create evpn service on Subinterface?

The goal is to make Arista switch to be a Router mode, so no vlan created on the switch, just SubInterface.

I have tested on vEOS-Lab and on DCS-7280 but no clue.

router bgp 65000
vlan 10
rd auto
route-target both 10:10010
redistribute learned

How to make above command attached to :

interface Ethernet2.10
encapsulation dot1q vlan 10

and ofc without creating vlan 10 on the switch.

Thanks in advance.

Posted by Aniket Bhowmick
Answered on March 31, 2021 10:39 am

Hi Devriza

Regarding your query:

  1. We understand that you don't want to create Vlans, and rather want to use a single interface as multiple subinterfaces which would carry different subnets and those subinterfaces would be used to perform the routing (will be used as next hop IP). Is this understanding correct ?
  2. If (1.) is true, then what you are trying to is called Symmetric IRB. In that case, you cannot extend the Vlan as the Vlan doesn't exist. So this configuration (which posted) is not valid. You can't have vlan 10 in "router bgp":

router bgp 65000
vlan 10

      3.  Instead, you need to stretch the vrf (considering you are using Vxlan as data-path) by providing the vrf a VNI ID. This method is called Symmetric Integrated Routing and Bridging . Using this method, you can advertise subnets between two VTEPs in EVPN (in specific vrfs) and the VTEP would be used to perform the routing.

4. You can find more details about Symmetric IRB here-

Let us know if this is not what you are looking for and if your requirement is something else.



Posted by Devriza Imanta
Answered on April 8, 2021 1:45 am

Hi Aniket,


Thanks for the answer, but the user wanted to make this happen on L2 services, not L3 services.

Is this possible in Arista?




Post your Answer

You must be logged in to post an answer.