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Hello I have two HP V1910-48G, which from my understanding are re-branded 3Com products. I'm running out of ports on both switches and both are deployed in different scenario's.

1) I need more ports and the new switch, HP V1910-24G, will be located in the same rack. Is there a reason to pay for expensive SFP ports rather than a CAT6 in this location? The switch will be used for VOIP, desktops with web browsing & simple file sharing.

2) I need more ports and the new switch, another HP V1910-48G, will be located on another floor. The entire run will be less than 100 meters. Does it make sense here to go SFP or maybe just run two CAT6 cables and somehow set them for teaming?

Thanks for your help. Today is the first day I'm attempting to learn about SFP ports, fiber cables, and the costs associated with this option!

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3 Answers

up vote 5 down vote accepted

GigE will run fine over Cat6 up to 100 meters (and, in most cases, Cat5e as well). In general, you would need to use fiber SFP modules if:

  1. Your cable run exceeds the maximum length for the cable type.
  2. Your cable run will be close to a significant EMI source (though this can be mitigated with shielded cable).
  3. The endpoints have different electrical grounding (e.g. different buildings).

Inside the rack, I see no reason to use SFP+fiber between the two switches unless you're completely out of 10/100/1000 ports and you can't vacate any. Even in that case, I'd suggest using 1000base-T SFP modules, since a Cat6 patch cord will likely be cheaper and more readily available than a fiber one.

Going between floors, you need to be aware of items 1 and 2, above. Item 3 probably doesn't apply, but it would be a good idea to verify with an electrician just in case.

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James' answer covers the lot well, just want to add one detail - the switch mentioned has SFP ports but not SFP+. If it had SFP+, you could plug in 10Gb modules, but SFP is limited to Gigabit Ethernet. Therefore if you are thinking about using something like LACP with two copper uplinks, you would need to do the same even with fibre to get the same performance. –  Robin Gill Dec 30 '11 at 19:32
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The 1910 has regular SFP ports, so it's limited to GigE only. However, unlike some HP switches, they aren't "dual-personality" ports, so using an SFP port doesn't disable the use of a 10/100/1000 port. –  James Sneeringer Dec 30 '11 at 20:34
    
Thanks guys! Much appreciated! –  paz Dec 30 '11 at 21:54
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They're not re-branded 3Com products, HP bought 3Com a while ago - so they're HP products.

As for your question, if you use good quality Cat5e/6 cabling and connectors and your run length is less than 100m then you may as well at least try using them first before having to turn to fibre-based SFP/SFP+'s later if you run into problems.

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Thanks @Chopper3 –  paz Dec 30 '11 at 21:54
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Fiber and SFP's are more future-proof for the short runs, pretty much the only advantage (and priced as such!)

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Thanks @Tim I think I'm going to stay away from fiber for these two projects. –  paz Dec 30 '11 at 21:55
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