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New Member

ISIS on dot1q/dot1ad-sub-interfaces on A9K



Is there any particular reason why ISIS on tagged sub-interfaces (both single- and double tagged) doesn't get a CoS value of 6 in the frames?

I know, I know... "Why would you run ISIS on a sub-interface?"

Indeed, but I have a rather special scenario where the core routers need to go through a switched network to reach each other, and for various reasons, these switches only leave us with the option of classifying traffic based on 802.1p, and thus we have to run the IGP on sub-interfaces.


We have/had the same issue on ASR1K, but on that platform we can use a "hack" by having a class-map match on destination mac-addresses for ISIS CLNS traffic and then set the CoS to 6 egress in a policy on the physical interface.

That hack is not, unfortunately, supported on 9K

Anyone with any insight?



New Member

Hmm, well, it seems to tag

Hmm, well, it seems to tag ISIS with CoS 6 when running on XR 5.2.0

My previous tests have been on 5.1.2.

Will try 5.1.3 as well.

Haven't been able to find anything in release notes, how come?

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