SFP GLC-LH-SMD

[borisenko_sa]

Hi!
I am interested in technical information about the Cisco GLC-LH-SMD.
Tell me, please, does this module support two ranges of 100Mbps and 1.25Gbps?

Thank You

[Marvin Rhoads]

The GLC-LH-SMD is a 1 Gbps transceiver and the speed is fixed at 1 Gbps only.

[soono]

If you want to know the spec that Cisco supports with GLC-LH-SMD, you should refer to the official data sheet.
https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/datasheet-c78-366584.html

Searching for “GLC-LH-SMD” in the TMG matrix shows that only 1Gbps is supported.
https://tmgmatrix.cisco.com/

[Joseph W. Doherty]

As Marvin notes, the GLC is an "effective" 1 gig transceiver. If you've seen 1.25 gig somewhere, I recall (?) that's the physical transmission rate, but .25 gig is consumed in overhead.

[Marvin Rhoads]

That's correct - the physical layer signaling of a 1 Gbps transceiver is 1.25 Gbps. However the encoding of Ethernet frames onto that results in a 1 Gbps data transmission rate.

https://www.cisco.com/en/US/tech/tk389/tk214/tech_brief09186a0080091a8a.html