SFP Speed and Compatibility

[David Grimm]

I've got a 3750 switch stack that I need to connect via single mode fiber to a Hirschmann switch (yuck). Anyways, the Hirshmann supports only 100Mbit fiber, where the only SFP module (GLC-LH-SM=) for the 3750 that supports single mode fiber is a 1000Mbit. If both ends are set to auto negotiate, will the 1000Mbit side negotiate at 100Mbit or is it 1000 only? I've seen many different answerrs and would hope to get some clarification from someone here. Looking for a solution that will quickly resolve a problem!

Thank you!

[glen.grant]

Fiber is single speed only , you would have to get a 100 meg sfp  to connect.

[David Grimm]

I haven't been able to find a 100Mb SMF SFP that is supported in a 3750 switch. Any chances you might know?

[Reza Sharifi]

have a look at table-7 in this link:

http://www.cisco.com/en/US/docs/interfaces_modules/transceiver_modules/compatibility/matrix/OL632702.html

HTH

[David Grimm]

Thanks for that link. According to that, there are no SMF SFPs compatible with the 3750 series. Not what I wanted to see lol.

[Leo Laohoo · Accepted solution]

use a media converter.

[David Grimm]

OK, so thanks everyone for the feedback. I went with the BlackBox media convertor. Its a 6 slot managed chassis and I bought the necessary single mode fiber to UTP modules that I needed. Hopefully this will do the trick!

[Reza Sharifi]

David,

On the fiber ports the speed is not negotiable.  So GLC-LH-SM will not work at 100Mb, only Gig.

HTH