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.