GLC-T vs GLC-SX-MM Between Switches

[mjensen323]

Hello,

When cabling between switches in an IDF, are there any gains  when using GLC-SX-MM vs plain GLC-T's?  

This is when the switches are not stack compatible. 

Thanks.

[Reza Sharifi]

As long as the speed is the same, there is no gains.

It is just one of them is via copper and the other one is fiber.

If the distance is short, copper is fine.

HTH

[Julio E. Moisa]

Hi

As it was mentioned previously, GLC-T is used for copper and GLC-SX-MM is used for fiber multimode, now if you are going to connect 2 switches using SFP's, these SFP's must be the same model. 

Hope it is useful. 

:-)

[denz_cruel]

I will prefer fiber specially configuring ports as a uplink. Advantage of Fiber over Copper are distance but you can still use it at short distance.

GBIC Module SFP Modules                     Maximum Cable Distance              Minimum Distance
WS-G5484 or GLC-SX-MM                      1804 ft (550 m)                               6.5 feet (2 m)
GLC-T                                                        328 feet (100 m)

Why fiber? 

1. Fiber optic transmission is faster.
2. Fiber optic transmission results in less attenuation.
3. Fiber optic cables are impervious to electromagnetic interference (EMI).
4. Light cannot catch on fire.
5. Fiber optic cables do not break as easily.

[Joseph W. Doherty · Accepted solution]

Fiber can be a bit better dealing with link loss than copper.

When using copper for inter switch links, you also sometimes have the option to use copper only ports.  Some switches provide extra capabilities and/or resources for their "uplink" ports, but if you're using a copper transceiver in such a port, you should continue to have those enhancements (if any).

To date, I've never had a problem using copper where I could.  In my experience, many engineers just go with fiber for all inter switch links because that's what they're used to using for inter switch links.

BTW, Cisco used to make a special "inexpensive" copper inter switch SFP gig cable for interconnecting (very) nearby 3560s, the Catalyst 3560 SFP Interconnect Cable, CAB-SFP-50CM.  Some vendors also use copper based stack cables.  So, perhaps, you might consider both these as possible endorsements that using copper vs. fiber, isn't by itself, an issue.