Cat9200L and Multimode SFP-10G-LRM

[jl81]

Hi,

A customer is using a pair of 3560-x with C3KX-NM-10G modules. The connection between the two switches are Multimode OM1 and approx 140 meters. 10Gb is running with no problems. SFPs is SFP-10G-LRM.

Now the customer is trying to replace the 3560-x switches with Cisco Cat 9200L, (fixed model with 4 10G uplinks).
It seems impossible to get the 10Gb link up. The SFP-10G-LRM isn't in the compatibility matrix, so it's maybe not a big mistery. But:

With a short distance (3-4 meters) between the c9200L switches the link is coming up fine, and SFPs working without issue.
If I connect one old c3560-x with a new c9200L, everything is working fine, even over the distance of 140 meters.
A c9300 with Cisco C9300-NM-8X, connected to c9200L works fine. Same SFPs, same fiber.

Why is the c9200L impossible to get working with SFP-10G-LRM and some distance over OM1?
The 'show interfaces transciever' is always showing optical values (~ -5dBM) far from the thresholds.

[marce1000]

 - A compatible SFP should be used as listed in  : https://tmgmatrix.cisco.com/?npid=1767

 M.

[g.dunham]

Have you tried mode-conditioning patch cables on each end?

[jl81 · Accepted solution]

Hello!

Yes, we tried many different cables, including mode-conditioning cables.

We did get a definitive answer from Cisco. The 9200L/9300L is missing EDC (electronic dispersion compensation), which is a pre-requisite for LRM-optics to function.

The solution for our customer was to replace their 9200L with 9200 switches (the model without L at the end).