GLC-SX-MM Transceiver

Unanswered Question
Mar 23rd, 2010

I am replacing GLC-SX-MM modules about 5 every week. I have them installed on different platforms mainly Cisco switches C6500, C3560, C3750 and bought them from different Cisco Vendors. By the way they are the Cisco ones.

Any ideas?

I have this problem too.
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Pronoy Dasgupta Tue, 03/23/2010 - 08:41

Hey Francisco,

Did you notice any similarity between the vendors? The easiest way to do that would be by using the show idprom detail command.

There is a section in the output of this command which tells you what vendor they SFP's are from, whether they are Avago, Cisco-Finisar and so on and so forth.

When you say that they become faulty, what exactly happens? Do they stop passing traffic, do they stop getting detected?



francisco_1 Tue, 03/23/2010 - 08:49


The switches stop detecting the modules.

I will check the vendor using show idprom command.

Any other reason why switches could just stopped detecting?  We always clean the fiber cables before plugging transceivers,

Giuseppe Larosa Tue, 03/23/2010 - 10:34

Hello Francisco,

Cisco does not produce GBIC or SFP on his own, they are produced by other vendors and customized with a specific eeprom.

So first GBIC were made by HP/Agilent and others.

I can say we had similar problems with SFP in one big campus, and our guess was that we had the problem devices from a not very good production set.

To be noted GBIC are bigger and look like more robust they deal the same power in a much bigger space volume so they experience a much lower power density and a lower "burning" probability.

Hope to help


Leo Laohoo Tue, 03/23/2010 - 14:11

Replace the SFP every five weeks????  I've never seen things happen like this!  Any error messages from the appliance before the failure?


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