GLC-GE-100FX vs GLC-FE-100FX Which to Use?

Unanswered Question
Apr 14th, 2008
User Badges:

What is the differance between the GLC-GE-100FX and GLC-FE-100FX modules. I thought all SFP ports on switches were Gigabit ports and thus the GE version would be needed for 100fx connectivity. Which switches would you use each SFP in? In particular I need to know which ones to use in a 2960-24PC-L switch and a 3560-8PC Switch.

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (3 ratings)
mattcalderon Mon, 04/14/2008 - 09:22
User Badges:
  • Silver, 250 points or more

If you look closer at that compatibility matrix that Paulo and I posted the other day the FE is for 100BASE-FX SFP module for 100-MB ports and the GE is for 100BASE-FX SFP module for Gigabit Ethernet ports. Not all SFP slots are Gig.

Here is the compatiblity matrix again.

For the 3560 here are the compatible SFPs





And for the 2960, Paulo stated that all of the 100FX SFPs are compatible.

NPT_2 Mon, 04/14/2008 - 09:45
User Badges:

Thanks Again, I guess I'm not really awake yet this morning.

What exactly constitutes a 100 Mbit or GE SFP port? I have never seen this in documentation and assumed they were all GE since GE SFP's seem to be the most common that I have used.

Also for the 2960's is it better to run the FE or GE part or does it really matter?

mattcalderon Mon, 04/14/2008 - 10:32
User Badges:
  • Silver, 250 points or more

If your switch is 10/100/1000 then you can run a GE SFP, but if your switch is 10/100 then you can't run a GE SFP. The 2960 you get will be either GIG capable on the uplink or not. If it is then get the GE SFP and if it's not the FE will do.

Take a link at this page for the 2960s

NPT_2 Mon, 04/14/2008 - 10:57
User Badges:

Hmm, interesting. The 2960-24PC-L has I am looking at has 24 10/100 ports and a dual-purpose uplink port 10/100/1000 or SFP. Considering the SFP supports Gigabit I would think the GE or FE would work ok on this one, which the compatibility document seems to agree with.

The Strange thing though is the 3560-8PC Switch. It also lists a dual-purpose uplink port 10/100/1000 or SFP. However according to the compatibility matrix it only supports the FE 100FX module. This is kind of strange considering that you can use a Gigabit SFP such as a GLC-SX-MM or just the 10/100/1000 uplink.

I think I'm just going to make it easy on myself and order the GLC-FE-100FX SFP's as they look to work in both of these switches ok.

mattcalderon Mon, 04/14/2008 - 11:26
User Badges:
  • Silver, 250 points or more

I found this link on the SFPs and it says the same thing you just expressed.

What is crazy is if you look at the switch matrix and it describes the 3560-8PC as 8 Ethernet 10/100 ports with PoE and 1 dual-purpose 10/100/1000 uplink. So it's weird that it has a 10/100/1000 uplink but does not support the GE SFP.

felixdav Mon, 04/14/2008 - 20:12
User Badges:
  • Cisco Employee,

The Catalyst 2960-24PC-L supports both SFP transceivers but the GLC-FE-100FX does consume less power than the GLC-GE-100FX.

The Catalyst 3560-8PC-S supports only the GLC-FE-100FX because the switch is fanless and the GLC-GE-100FX generates too much heat.

NPT_2 Tue, 04/15/2008 - 08:07
User Badges:

That makes sense. Is there any advantage to using the GLC-GE-100FX over the GLC-FE-100FX in switches that support both?

It sounds like the FE does the same thing as the GE but also uses less power and heats up less? Is there any reason to use a GE over an FE if they both are supported?

garry cordess Sun, 03/02/2014 - 01:47
User Badges:


I assume that there isnt any isues connecting switch 1 with a GLC-GE-100FX to switch 2 with a GLC-FE-100FX is there?

I cannot see why but would be good to know.

Also has anyone exceeded the 550 metre distance on GLC-SX-MM with OM3 and then tested for signal reduction?

Maybe n% reduction per 100 metres over the 550 metre recommended max.



NPT_2 Mon, 03/03/2014 - 09:21
User Badges:

Since I posted that message years ago we have implimented several GLC-GE-100FX to GLC-FE-100FX links without any issues (which one we ended up using really depended on switch support).  As for th GLC-SX-MM you can only get 550 Meters over 50 μm Multimode Fiber, if you have 62.5 μm multimode fiber you only get 220 Meters maximum.  I'm not sure about over 50 μm fiber but I have personally tried running a few hundred feet over the 220 Meters over 62.5 μm MM fiber and it wouldn't even link in.  Thus on some links rather than running new single mode fiber (or using LX optics and mode conditioning cables that are supposed to get you out to 550 meters over 62.5 μm multimode) we just used 100FX optics until single mode cable could be installed when needed. 


This Discussion