nanog mailing list archives

Re: CWDM question


From: Jared Mauch <jared () puck nether net>
Date: Thu, 12 Dec 2013 20:15:40 -0500


On Dec 12, 2013, at 8:11 PM, Keith <kwoody () citywest ca> wrote:

Hi.

We are doing a fiber link between us and another SP using CWDM.

There is traffic flowing just fine at the 1310 wave, and have recently added a
1471 wave.

On the 1471 wave there are some problems with it. From our perspective, and we
have packet captured this, we are transmitting data to them, but they say they
are not seeing anything. We are receiving from them, and while we show that
packets are leaving our interface to them, they are getting nothing at all.

There are good light levels between the two locations and do not understand
why they are not seeing traffic from us even though we are sending it. Our packet
counters show we are transmitting to them and receiving from them.

Is it possible to have RX and TX light and things appear to be ok, but have the
RX on their side fubar in some way that it is not operating correctly in that our
traffic is not reaching them?

Are you using fixed optics or tunables?  Are transponders involved for the CWDM side then you have “client optics” at 
850nm or 1310?  Is there a filter involved?  Do you have a light meter?  What do the optics show for the various light 
levels and frequencies involved?

- Jared

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