[c-nsp] IOS-XR accepted duplicate subnet configurations for interface

[Nikolai Nespor]

Christoffer Hansen <cdh at nianet.dk> writes:

Hi,

> I have recently run into a case with an ASR9k router running IOS-XR
> v5.3.4. Were I by accident put an identical secondary subnet on a 2nd
> interface located inside the same VRF as the first one. It is even a 2nd
> sub-interface to another sub-interface on the same main interface.
>
> Case-in-point: The router accepted the configuration commit without
> complaints and of course traffic then stops flowing.

AFAIK, this is the standard behavior for IOS-XR.

> Normally I would not expect this to be possible to do. And would expect
> the router to output a warning telling me I am trying to commit an IPv4
> address|subnet already configured on another interface in the same VRF.

A warning should have been logged by the router. Please check the logs
for an entry containing:

%IP-IP_ARM-3-CFLCT_FORCED_DOWN

Regards,

Nikolai

-- 
Ich verwalte sie. Ich zähle sie und zähle sie wieder.
Das ist nicht leicht. Aber ich bin ein ernsthafter Mann.
\
 ---> Antoine de Saint-Exupery, "Der kleine Prinz"