Question about Cisco Switches and SFP Transceivers - MMF vs SMF

[okelhemin]

I'm looking at documentation from Cisco's site and I see that the WS-C3750G-12S-S switch supports GLC-GE-100FX as an SFP transceiver - which is for MMF.

Apparently, a site is running SMF everywhere but connecting things to this switch. I see a few different 100-MB SMF transceivers - but none of those are listed to be supported with this particular switch.

A few questions.

1. Can you run SMF SFPs in the 3750G-12S? I can't find documentation supporting this.

2. Can you use MMF SFPs with SMF? I thought that was a no-no and you have to use the right SFPs for the type of fiber that's ran.

[paul driver]

Hello

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@okelhemin wrote:
Can you run SMF SFPs in the 3750G-12S? I can't find documentation supporting this. < if the switch supports fibre sfp then it should support either SM/MMF modules

Can you use MMF SFPs with SMF? I thought that was a no-no and you have to use the right SFPs for the type of fibre that's ran. < I would say its not recommended however you could use media converters or fibre conditioning cables( sm-mm only) to accomplish this.

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[Joseph W. Doherty]

For 100 Mbps fiber or gig fiber?

The 3750G supports (or at least it did before it went EoL) many gig SFPs that should work on SMF.  (This isn't too surprising as the G suffix is for gig.)

Cisco 3750G SFPs its IOS doesn't support might work if you configure switch to support non-Cisco transceivers.  However, if you're asking about supporting 100 Mbps, unlikely the 3750G SFP ports will support.

[Tom Randstrom]

Below is the link to the transceiver compatibility tool for the module series in question:

ttps://tmgmatrix.cisco.com/?si=WS-C3750G

Connecting a MMF transceiver to SMF is not a supported configuration.