On Sun, 5 Apr 2020 at 11:07, Mark Tinka <mark.tinka@seacom.mu> wrote:
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'm not sure what 'globally our IS-IS domain runs 8000 bytes' means. Your LSP MTU is like 1492B, there isn't a mechanism to fragment and reassemble LSP in-transit. ISIS network doesn't support different MTU sizes and I've not heard anyone being brave enough to increase LSP MTU above 1492B. The only thing that is larger in your network is hellos, and I'm not even sure how that works, considering 802.3 cannot signal larger frames than 1500B. -- ++ytti