IS-IS on FRR - Is Anyone Running It?

Sun Apr 5 08:03:56 UTC 2020

On 4/Apr/20 19:16, John St.Martin wrote:

> Mark, Thanks for sharing your experiences with FRR. I don't work with
> IS-IS, but have found the development to be very active and fixing
> reproducible bugs quickly.
>
> It look like FRR put a patch in for the bug you referenced and have a
> test build from 3/21 available which allows for up to 16k MTU
> @ https://ci1.netdef.org/browse/FRR-FRRPULLREQ-11364/artifact
>
> I hope this helps and please continue to share your progress with the
> community.

Thanks for the feedback, John. It's great to hear this issue is being fixed.

So I'm not really trying to get IS-IS to run at a high MTU, as that
doesn't really do anything for the data plane. What I am really looking
for is a way to tell IS-IS to run a specific MTU.

In my network, even though we can carry up to 9,192 bytes in the data
plane, we manually set IS-IS to operate at 8,000 bytes. This is due to
VMware's limitation to address an MTU larger than 9,000, and we use it
to run CSR1000v for our route reflector. So globally, our IS-IS domain
runs 8,000 bytes.

I am just looking for a way to tell IS-IS, in FRR, to run at 8,000
bytes, which can be done without needing to fix the current bug in 7.2.
I just can't seem to find any configuration settings to do this, or
anyone that knows what they are.

Mark.