topic Re: Purpose of L2LISP0 Interface in Software-Defined Access (SD-Access)

Purpose of L2LISP0 Interface

jan.habicht — Fri, 28 Apr 2023 08:03:01 GMT

Hi,

In our SDA fabric, we have a separate L2LISP0 interface on each edge node for each VLAN (e.g. VLAN 1021 -> LISP0:8188). These interfaces are normally in the "up" state.

In certain cases, our NMS reports that one of the L2LISP0 interfaces on a specific edge node goes into the "down" state.

We would like to understand the purpose of these L2LISP interfaces and what could be the reason why an L2LISP0 interface occasionally goes into the "down" state?

Re: Purpose of L2LISP0 Interface

Andrii Oliinyk — Sun, 30 Apr 2023 07:40:32 GMT

just thoughts aloud. before the cisco lisp came into play, there was underlay with its IEEE/ISO/OSI/RFC suits system. other words, probably there was no L1-L3 sign of life to keep L2LISP interface alive imho. if u know what i mean

Re: Purpose of L2LISP0 Interface

jedolphi — Thu, 04 May 2023 22:40:21 GMT

L2LISP interface is used for L2 switching between endpoints in same access VLAN (as opposed to routing between endpoints in different subnets). As best I can tell the L2LISP interface should not flap - in the lab I tried removing all endpoints, deleting access VLAN, etc, but cannot get it to flap. To explain L2LISP interface flap please consider raising TAC case.

Re: Purpose of L2LISP0 Interface

Andrii Oliinyk — Thu, 04 May 2023 23:05:53 GMT

with SDA\LISP automation there r always some tricks like implicit 0.0.0.0 route to Null or LISP-process etc. u cannot ensure u've been deleting all dependencies. but i totally agree that this case is for TAC :0)