Weird 4500X v 2960X issue

[sdawson35]

so we have a stack of 8 x 2960X switches with te1/0/1 and 4/0/1 configured as trunked uplinks to our 4500X core (both using 10GBase-SR sfp's) , works fine no issues.

We also have 3 additional 2960X switches hung off of gi1/0/50, 2/0/50 and 3/0/50 also trunked and working fine (using 1000BaseSX sfp's).

However when i move these to the core they fail to connect , the core recognizes the 100BaseSX sfp and throws up no errors , yet no connection (Line down/protocol down) is made , put them back in the 2960 and they come up straight away.

Anybody got any idea's ?? (please)

[rasmus.elmholt]

Hi

Is it original Cisco SFPs?
I have seen the same with a bunch of PeakOptical SFPs where they either wasn't recognized or the SFP was recognized but the link didn't come up. The SFPs worked fine on other platforms or other switches(2960x-24 ports vs. 2960x-48 ports)
After I exchanged with some SFPs(PeakOptical as well) with a different revision number/firmware version it worked.

[Mark Malone]

Hi
4500x Support 1000SX as below , they work in mine are the TX/RX fibres matching up can you see the light when you look down the fibre , try cross the fibre pair , you have a L1 issue , either SFP/Fibre

#sh ver | i 4500X
License Information for 'WS-C4500X-16'
cisco WS-C4500X-16 (MPC8572) processor (revision 9) with 4194304K bytes of physical memory.
MPC8572 CPU at 1.5GHz, Cisco Catalyst 4500X
1#sh int t2/1/12 | i SX
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX
xir-b100uds01#

[rasmus.elmholt]

NEVER look into a fiber cable... It can damage the eye.
Use the right tools to measure the effect in the fibre cable.
Do the show interface transceiver show any receive effect?

[Mark Malone]

doing it years never had an issue just be careful doing it , most users wont have a fibre tool handy to test with
that command will only work on switches that support DOM and the SFP must too to be able to support it too

[Joseph W. Doherty]

"doing it years never had an issue . . ."

On what kind of optics? Reason I ask, it believe that's a very bad idea with the more powerful laser based optics, such as ERs.

[Mark Malone]

most just the 1GB SM-MMD or SR 10GBs multi mode i wouldn't do it on a single mode , i just cuff the top of the fibre and check can i see the light , then cross the fibre to match

[sdawson35]

Hi All,

Thanks for the responses !, Issue was finally resolved in a very round about way.

1. fibre between devices was mixed, some single mode and some multimode , once we had worked out what was what and corrected the also incorrect patch leads we had some success.

2. purchased some genuine Cisco labelled SFP's NOT SFP+'s.

So moral of the story match correct fibre types and patch leads  - dont assume that what you are told is correct and buy genuine.