CWDM question

Keith kwoody at
Fri Dec 13 03:17:28 UTC 2013

On 12/12/2013 5:15 PM, Jared Mauch wrote:
> On Dec 12, 2013, at 8:11 PM, Keith <kwoody at> 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
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

Only 1310 and 1471 in use.

We are 800+km away from the site so its hard to get some hands/eyes there at present.


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