[c-nsp] MTU and PMTUD

[Marcin Kurek]

>  https://www.rfc-editor.org/rfc/rfc8654.html

Thanks!

> But it was [8936, 1240].min - so it was 'negotiated' here to the
> smallest? If you change the 8936 end to 1239, then that will be used,
> regardless who starts it.

Yes, but why would XR advertise 1240 if I'm using 'tcp mss 8936' for that
neighbor?
Initially I thought that the whole point of this command is to set MSS to a
fixed value of our choice.

Kind regards,
Marcin


czw., 8 gru 2022 o 10:31 Saku Ytti <saku at ytti.fi> napisał(a):

> On Thu, 8 Dec 2022 at 11:25, Marcin Kurek <md.kurek at gmail.com> wrote:
>
> > Interesting, but why would 'sh run' or 'write' raise an interrupt?
> > Isn't this a branch in code that handles the CLI?
>
> Maybe to access NVRAM? I don't know for sure, I didn't pursue it, I
> just know I could observe it.
>
> > I'm not sure if I'm reading it right - on the one hand, the interrupts
> are disabled, but on the other hand, some CLI commands actually raise them?
>
> I don't know if IOS does polling or interrupt for NIC packets, but
> there are tons of reasons to raise interrupt, not just NIC.
>
> > Would you mind elaborating on why going above 4k would mean "newish
> features" and what are they?
>
> https://www.rfc-editor.org/rfc/rfc8654.html
>
> > So here CSR1kv is initiating the connection to XR box advertising MSS
> 8936 (as expected).
> > However, peer MSS is 1240, which is not quite expected, considering XR
> config:
>
> But it was [8936, 1240].min - so it was 'negotiated' here to the
> smallest? If you change the 8936 end to 1239, then that will be used,
> regardless who starts it.
>
> --
>   ++ytti
>