[j-nsp] Trouble with 100G link MX204 <-> Dell S4100F-ON

[Saku Ytti]

On Wed, 18 Mar 2020 at 19:49, Emmanuel Halbwachs
<Emmanuel.Halbwachs at obspm.fr> wrote:

> > Thanks. I'll upgrade and let the list know if it works without the FEC
> > knob.
>
> Just upgraded to 19.4R1.10: same situation, FEC91 is needed to bring
> 100G links up.

100GE standards either mandate FEC91 or do not mention it. But there
is nothing at all wrong running FEC91 for example in LR4, a lot of
good reasons to do so.

The problem of course is, you have to somehow know if _this_ optic
needs FEC91 or not, and as far as I know they rely on EEPROM to
understand that , and that seems a bit fragile.

Personally if I control both ends, I'd always run FEC91. You can fix
problems before they become customer symptomatic and you can approve
new circuit for service immediately, as FEC91 will be constantly
sending data, so you'll immediately know at turn-up if link is good or
not. No need for fragile ping-tests.

Going forward, it's unlikely new standards without FEC will happen, as
it's a cheap trick to add reach.
-- 
  ++ytti