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Single Mode Fiber use on Cisco 3750 switch

We typically have multimode fiber runs across our very small college campus. We are buliding a new building that is far enough away that we need to run a single mode fiber to tie the new building to the backbone. I will be deploying the Cisco 3750 switch using GLC-SX-MM SFP's. I am assuming the Cisco 3750 will handle the single mode but what SFP's are recommended? I see that my options are a GLC-LH-SM and GLC-ZX-SM. Is the difference simply the reach (10km verse 70km)?


Re: Single Mode Fiber use on Cisco 3750 switch

Thats pretty much it. They run on different frequency 1310nm and 1550nm if I remember right.

The LH ones are most likely lh/lx which allows them to run over multimode fiber which in some cases allows multimode fiber to be run rather than singlemode when you are just over the distance for SX (850nm)

The ZX are quite expensive so I wouldn't buy them unless you really need them.

Re: Single Mode Fiber use on Cisco 3750 switch

You will want to use the GLC-LH-SM SFP, as the GLC-ZX-SM SFP does have a minimum distance requirement of 15.5 miles unless you have an attenuator. The ZX are extremely long haul as to where the LH are long haul interface converters.


Re: Single Mode Fiber use on Cisco 3750 switch


In addition to the excillent informations provided above, here's a compatibility matrix for Cisco GBICs and SFPs to check if a specific GBIC/SFP is supported on specific switch model or not -

-> Sushil

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