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.
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
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 Fixed optics, there are no transponders, just a passive mux. No filters, though there is a
On 12/12/2013 5:15 PM, Jared Mauch wrote: 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. 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. Thanks.
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. jms
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.
If you're also doing 1310 does that mean there's a splitter cable inline with the passive mux? If so, some are cheap and don't filter well outside of the 1550 band. On Dec 12, 2013 10:23 PM, "Keith" <kwoody@citywest.ca> wrote:
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.
participants (5)
-
Christopher Costa -
Jared Mauch -
Justin M. Streiner -
Keith -
Sam Roche