CWDM question

Justin M. Streiner streiner at
Fri Dec 13 15:12:34 UTC 2013

On Thu, 12 Dec 2013, Keith wrote:

> Fixed optics, there are no transponders, just a passive mux. No filters, 
> though there is a pad on our side.
> Light levels on our side are good and within spec. I have been trying to find 
> out from the SP what theirs
> are at presently, but when the circuit was first lit levels were taken and 
> found to be within spec on both
> ends.

Another possibility is that the fiber you're using has higher attenuation 
at 1471nm than at 1310.  While 1471 is outside of the 'water peak' band 
(E band - 1360-1460nm, centered at 1383nm, iirc), the type of fiber could 
could still have higher attenuation that runs into the S and O bands.

If replacing optics doesn't solve the issue, you'll probably need a test 
set that can test specifically at 1471 nm.


More information about the NANOG mailing list