nanog mailing list archives

Re: CWDM question


From: Keith <kwoody () citywest ca>
Date: Thu, 12 Dec 2013 19:20:25 -0800

That is whats next. They took down the whole fiber instead of just the 1471 wave to test
which killed transit...grrr..

They say their tx/rx are within spec.

Next is jumpers and sfp swaps I guess.

Thanks.
On 12/12/2013 6:40 PM, Sam Roche wrote:
If you have a CWDM optical power meter and light source, see if you can measure the power level on the receiving end and verify that it is within the spec of the SFP. Maybe it is a bad jumper or port on the 1471 receive on their end or send on your end.

If the two switches can be brought to the same location, you might also want to connect them together using short jumpers, but make sure you have a power meter to ensure you use the proper attenuators to avoid burning out your optics. This would rule out your fiber and mux in case it an issue with an appliance or SFP. I've had CWDM SFPs burn out for no apparent reason twice now.

*From: *Keith
*Sent: *Thursday, December 12, 2013 8:11 PM
*To: *nanog () nanog org
*Subject: *CWDM question


CWDM question

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?

Thanks.










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