IS-IS on FRR - Is Anyone Running It?

Mark Tinka mark.tinka at
Mon Apr 6 12:10:08 UTC 2020

On 6/Apr/20 12:57, Dale Shaw wrote:

> Since vsphere67u3 (ESXi 6.7 U3), you can set an MTU of up to 9,190 bytes:

So we moved from 6.0 to 6.7 last year, when we refreshed the servers.

Not sure why they hid the fact that they can breach the 9,000 mark:

> The host UI doesn't let you go >9000 bytes so (for now) you need to
> use the CLI.

Yeaaaaah... RR's are critical infrastructure. I'd prefer not to mess
with them beyond what is necessary :-).

> Are your FRR VM vNICs attached to standard or distributed vswitch port
> groups?

So we only worry about this on our RR's.

Other VM's that may be running are not a huge concern.

Despite our network being able to carry 9,192 bytes, we only guarantee
9,000 for services and customers, end-to-end. Same applies to internal
services we operate.


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