IS-IS on FRR - Is Anyone Running It?

Mon Apr 6 07:49:22 UTC 2020

On Mon, 6 Apr 2020 at 10:36, Anoop Ghanwani <anoop at alumni.duke.edu> wrote:

>> 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.
>>
> Probably this method:
> https://en.wikipedia.org/wiki/EtherType#Jumbo_frames

Mikael Abrahamson and I quickly looked at this, some platforms (IOS,
IOS-XR, EOS) use ethernetII + 8870, but only for hellos and revert
back to standard 802.3 after. Some platforms (Junos) accept 8840
hello, but do not send it.
So after 1500B MTU detection does not work by-standard and everyone
has been forced to implement CiscoISIS to just get ISIS up, and Cisco
is forced to accept subMTU hello equally to interoperate with non8840
hosts.

It's really time to kill 802.3 and CLNS and do pure ISIS over
ethernetII+IPv6, no one really understands how all this works, it's
complex and fragile.

-- 
  ++ytti