[j-nsp] BGP VPLS MTU for pseudowires

[Dejan Jaksic]

thanks Saku!

Yes PWE signalling MTU is just signalling and not related to data plane, we
have solution to move PWE UP.
Anyway - if you use static MTU under vpls instancein Junos you do see MTU
correctly matched on Cisco side (not sure do you have XR box in your
network)?

Dejan


On Tue, Mar 6, 2018 at 9:32 AM, Saku Ytti <saku at ytti.fi> wrote:

> Hey Dejan,
>
> I wouldn't worry about this. The MTU check never should have existed
> in pseudowire signalling. It's even vendor dependent how they
> calculate they MTU, so you might have exactly correct MTU in A-B end,
> but you will get MTU mismatch because they calculate different thing
> in A and B end.
>
> I personally signal statically defined MTU, because that is more
> transferrable, you may get B end which does not support ignore, but if
> A end supports ignore + statically defined MTU, you can always get the
> circuit up by just configuring A end correctly.
>
> There is absolutely no impact to dataplane in signalling the MTU
> correctly or incorrectly, it's just misguided attempt to avoid
> configuration mistakes.
>
> On 6 March 2018 at 10:17, Dejan Jaksic <dejan.jaksic at gmail.com> wrote:
> > Hi all,
> >
> > we are testing interop for L2VPN VPLS BGP AD + signaling between Cisco
> > ASR9k and Juniper MX.
> > We cannot make pseudowire between Juniper and Cisco UP unless we ignore
> MTU
> > mismatch, othervise during BGP signaling it states MTU mismatch error and
> > PW stays down.
> > When we use ignore mtu mismatch pseudowire goes up but under Cisco l2vpn
> it
> > states 1500 bytes on Cisco and "unknown" on Juniper side.
> > Looking at Juniper lsi interface under vpls connection for MTU it states
> > "unlimited".
> > Question - how to set up MTU for PWE on Juniper without ignore mtu to
> have
> > VPLS PW up between Cisco and Juniper VPLS?
> >
> > Thanks,
> > Dejan
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/juniper-nsp
>
>
>
> --
>   ++ytti
>