[a-nsp] Weird L1 issue ...

[Bryan Holloway]

Got a weird one ...

7060CX running 4.28.9M (near-side)

Trying to bring up a 100G link between it and another 7060CX (far-side) 
with a carrier providing a wave in-between.

The near-side Arista is new. Prior to its install, we had this circuit 
plugged into a Mellanox, and it works fine -- no issues whatsoever.

When we move the circuit to the near-side Arista, it won't come up. No link.

Tried new optics, no change.

Actually swapped out the switch itself, no change.

Even if we pull the Arista optics and plug it into the Mellanox, it 
works fine.

Normalize the circuit, it just won't come up.

We see good light from the carrier, and the carrier says they see good 
light from us.

Are there any knobs I'm missing, or can anything think of a reason for 
this behavior?

I'm baffled.