IS-IS on VRF-LITE didn't set ATTbit

[Danilo Silenzi]

Hi all,

I have an issue on IS-IS in vrf-lite.

PE rotuer receive specific network and default from MP-BGP session with RR.

There is a mutual redistribution between MP-BGP and IS-IS on VRF-OUTSIDE.

On IS-IS process in VRF-OUTSIDE there is command to generate default-route

On rib of VRF-INSIDE there is default route.

On RA miss default route, and in ISIS DB the ATTbit is 0 for all LSP.

There is same specific configuration to do to permit IS-IS work properly in vrf-lite (ex: in ospf there is vrf-lite capability command)?

Thanks.

[Harold Ritter]

Hi @Danilo Silenzi ,

This should work if the following conditions are met.

The session between outside and inside is a level-2.

The session between PE and RA is a level-1.

Regards,

[Danilo Silenzi]

Hi Harold,

thank for your support.

I confirm you the session are L2 between outside and inside, and L1 between inside (PE) and RA. But on routing table of RA I don't find the default route, and on ISIS DB the ATTbit is 0 for all LSP.

Thanks.

[Harold Ritter · Accepted solution]

Hi @Danilo Silenzi ,

I should have added a 3rd condition, which is that the ISIS area address should be different between outside and inside.

By the way, these rules are not specific to vrf-lite. They also apply to a standard ISIS scenario. If the L1L2 router does not have an L2 adjacency to a router in another L2 area, it will not set the attached bit.

Regards,

[Danilo Silenzi]

Thank you Harold,

Now the ATTbit is set on LSP on RA.

Thank you very much.

Have a nice day, Danilo.

[Harold Ritter]

You are very welcome @Danilo Silenzi ,

Have a great day!