[c-nsp] LX vs LH Transceivers

[Lamar Owen]

On Monday 15 June 2009 07:08:03 pm Justin Krejci wrote:
> 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.
[snip]
> 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. 

I've seen random issues with our 12012 with 1 port GE linecards linking up 
with a Catalyst 5509's GE port before; have no idea if they are related or 
not, but disabling autonegotiation on the Catalyst seemed to fix it.  The link 
would intermittently come up on the Cat 5509, and the link showed up on the 
12012, but would not be stable until disabling negotiation on the 5509.  I 
realize that's old hardware, but even the latest 6500 stuff inherits more from 
the old Catalyst line than it does from the 7200 router line.

In our case, the 12012's LC links up fine with an Extreme Summit1i, with a 
7401ASR's GE port, with a 7507's GEIP and GEIP+, and with a 7200 NPE-G1's 
port. Had issues with the Cat 5509 gig ports (both on the SupIIIG and the 
three port gig card) only.  Haven't tried with our 7609 yet, or with a Cat 
8500, or with a Cat 5500's 9 port gig etherchannel card.