[j-nsp] FEC on 25G-LR links between Juniper and Arista

[Sebastian Wiesinger]

Hi,

we've run in some weird issue with 25G links and FEC between Juniper
QFX5120 and Arista.

We have functioning links using 25G-SR optics and FEC108
(Reed-Solomon) error correction. On Arista thats default, on the QFX
we use

set interfaces et-0/0/46 gigether-options fec fec108


This works.

Trying the same on another switch with 25G-LR optics doesn't work.

The only way to get the interface up is to either

a) disable FEC on Arista
or
b) setting both Arista and Juniper to the (inferior) FEC74 (Fire-Code).

Any idea why that is? Does anyone here have working 25G-LR links using
Reed-Solomon FEC between Arista and Juniper? Also tried FEC91 on
the Juniper side without success.

Best Regards

Sebastian

-- 
'Are you Death?' ... IT'S THE SCYTHE, ISN'T IT? PEOPLE ALWAYS NOTICE THE SCYTHE.
            -- Terry Pratchett, The Fifth Elephant