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Cisco SFP-10/25G-LR-S and mode-conditioning at 10Gbit

We're considering upgrading our site/branch L3 and fiber distribution switch at numerous sites from models with 1Gb SFP interfaces to Catalyst 9500s with SFP28 interfaces.  The access switches in the downstream closets are Catalyst 2960X.  Most of the existing fiber plant is multimode OM1 and while we're evaluating replacement, that will be a long-term and expensive process, not lending itself to this round of funding.


At some other sites where we've already gone 10Gb I have used SFP-10G-LR-M optics with success along with mode-conditioning cables to get the distances I need.  I have also tested SFP-10G-LR-S optics and confirmed I can use them on multimode fiber with mode-conditioning cables, I have not tried pushing the distance to the same extent as the LRM optics but it seems to work in those applications I've tried.  


I have two questions. 


First, can the SFP-10/25G-LR-S function with mode-conditioning at 10Gbit with similar characteristics to the SFP-10G-LRS on OM1 cable, and interoperate with the SFP-10G-LRS at the other end of the link?


Second, and this is more because I've found conflicting information, does the SFP-10/25G-LR-S operate at 10Gbit speed in a Catalyst 2960X WS-C2960X-48FPD-L and/or WS-C2960X-24PD-L?


The main reason for the second question, is that if SFP-10/25G-LR-S will operate in the 2960X at 10Gbit, then I can go with those optics now, and then if/when we upgrade to Catalyst 9K access switches, simply slot them into the new switches.  If they don't function in any capacity in the 2960X then I'll have to consider other solutions, and put off purchasing the 10/25 optics until I have the access switches that use them.




Re: Cisco SFP-10/25G-LR-S and mode-conditioning at 10Gbit


  1. It seems the SFP-10/25G-LR-S can only be used with single mode fibre. Have a look at the following link:
  2. The SFP-10/25G-LR-S does not support the 2960 switches. You can find compatibility by submitting the switch or sfp at the following link:



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