There appears to be a fair amount of threads online about using LX and LH together on a SMF link. I have a situation where there is a 7206VXR with an NPE-G1 that has a LX GBIC installed that is talking via SMF to a 12000 series router to one of our providers that is using an LX transceiver. This gigE link has been up and running happily for a while.
We are running into some performance issues on the 7200 when under load so we have a 6509 sup720 3bxl. The sup720 has one sfp port and one sfp/rj45 combo port. We have one GLC-LH-SM SFP transceiver installed into the sfp-only port but when cutting over the above mentioned link from the 7200 to the 6509 we get no eth link at all. We verified fibers are clean, light levels are within spec and strands connected in the correct tx/rx slots on the transceiver. A simple hard loop at the FDP causes the gig interface to come right up on the 6509 so I know the transceiver and gig port are producing and receiving light at a hardware level but it seemed odd this was not working when talking to the provider's LX GBIC. Everywhere online that I could find seems to indicate LX and LH are 100% compatible with each other and that Cisco even uses these two interchangeably (to the dismay of some). http://marc.info/?l=cisco-nsp <http://marc.info/?l=cisco-nsp&m=120612428712150&w=2> &m=120612428712150&w=2 http://en.wikipedia.org/wiki/Gigabit_Ethernet#1000BASE-LX When talking with this provider they are adamant that their Cisco LX equipment is not at all compatible with regular Cisco LH equipment and mentioned that they are not using standard IOS but are using some customized OS on their Cisco which is why there is this incompatibility. This to me seems very suspicious like they don't want to troubleshoot this problem but I can't dismiss their claims as invalid since I am not real knowledgeable in this regard. They also claim they are not able to support LH connectivity for this circuit due to this compatibility. From what I've read it seems the LH/LX compatibility is really more of a hardware difference and software driving the hardware would have no real bearing on this but again I don't have anything to back up my line of thought. Do I need to press my provider a little harder on this issue or are their claims true/possible and I am just going to have to get an actual "LX" SFP for this circuit or figure something else out. Thanks! Justin Krejci _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/