[j-nsp] QSA adapters and MTU

[Olivier Benghozi]

Actually 1G ports are «10G ports operating at 1G speed».
So, configured as 10G ports on chassis side, giga-ether speed 1G on
interface side.

Le ven. 3 nov. 2023 à 16:53, Chris Wopat via juniper-nsp <
juniper-nsp at puck.nether.net> a écrit :

> I can test this on our lab box, but cant get 'supported platform' in the
> chassis config for
>
> port 15 {
>     ##
>     ## Warning: statement ignored: unsupported platform (mx304)
>     ##
>     speed 1G;
> }
>
> even though it's passing on https://apps.juniper.net/port-checker/mx304/
>  ¯\_(ツ)_/¯
>
> could perhaps work harder on getting that config right later. it
> certainly lets me commit a ge config with that MTU though. when set as
> speed 10g, I can see the 1g optic inserted, as well as DOM, but it won't
> link.
>
> --Chris
>
>
>
> On Fri, Nov 3, 2023 at 10:16 AM Ola Thoresen via juniper-nsp <
> juniper-nsp at puck.nether.net> wrote:
>
> > On 03.11.2023 16:04, Chris Wopat wrote:
> >
> > > We use them on MX304 at 10g, primarily to get DWDM SFP+ to work. MTU
> > > is fine, it's 9k as a part of LACP on a recent deployment. The adapter
> > > simply passes through lane :0 to the port when configured as QSFP+. If
> > > you insert the adapter and no optic, the device is unaware of its
> > > existence - you only see the SFP+ info.
> > >
> > This is the same use case as for us, and my understanding is exactly
> > that they are just passing a single lane through, and should not really
> > know anything about packets or ethernet frames or anything.
> >
> > But still - people more knowledgeable than me - assure me that there is
> > a limit of 2008 Bytes MTU - at least for 1G.
> >
> > I just can't find this documented anywhere, and I would have thought
> > that more people would have made more fuss about it when they start
> > using it if this is a real issue.
> >
> >
> > > We haven't tested in prod on 1g but i think we did in the lab. can
> > > probably toss something in there if you're really curious. I think the
> > > juniper supported optic page lists QSA adapter support or not. I
> > > thought it was generally supported with Junos 20+ nowadays.
> > >
> > Yes. They list QSA adapter as supported, also for 1G optics, and don't
> > write anything about any MTU limitations in the Hardware Compatibility
> > Tool.
> >
>

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