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I'm expanding the switch in our rack to a 10 GbE fiber internet feed. Specifically:

  • we have an HP 2910al
  • will expand the switch with a J9008A 2-port 10GbE SFP+ module
  • will plug in 1 (2?) J9150A 10Gbase-SR tranceiver

Our HP vendor tells us that we need two transceivers, but I cannot find any documentation to that effect. And the images of the transceiver seem to indicate each one has two physical cable ports. But... J9150A transceiver

Having never actually worked with 10GbE, fiber or SFP+ before I thought I'd hask the boffins here on Server Fault before placing any orders. Please save me from wasting time and/or money!

Must I install SFP+ transceivers in pairs?

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4 Answers 4

up vote 2 down vote accepted

I haven't worked with 10GbE but AFAIK you only need one fibre connector at each end (unless you're bonding at a guess). Is you vendor confusing the fact you need one at each end ?

You can't mix the interface types because of the cable. At least that's my understanding. We use them for Gig fibre.

You might be surprised that you can pick these little modules up for about £30 off eBay and the likes. Vendors try and force you to buy their massively inflated brand but have a quick look before you buy and you'll probably find they're really cheap elsewhere. I think we got a couple of perfectly good used ones of eBay for £15 each to have some spare in stock.

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The quote was coming in at $2k...each! So, yeah, I'm aggressively trying to save us some money. –  Stu Thompson Apr 4 '11 at 12:51
    
FWIW obviously shop with caution but 3com's docs all said 3com only and listed part numbers for their SPF modules ... the diversely sourced varieties we tried all worked. –  Jonathan Ross Apr 4 '11 at 15:14

No, you can use only one 10Ge SFP (of course - one to one on both sides)

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I also can't find any evidence that J9008A needs to use both ports at once. Have you asked your ISP what it looks like on their end?

Short note about buying SFP:s on eBay, it's becoming more and more common that switch manufacturers firmware only accept their own branded SFP:s, so there could be reasons to stick with HP on the SFP+:es, no matter how tempting it sounds with £30 for a 10GbE SFP+.

(Sure it wasn't 1000 MBit, 2 Gb or 4 Gb ?)

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Yea, I read that to. I'm inclined to pass on Jonathan Ross' suggestions, and to stick with HP parts. That said, a J9150A retails at over $2k though HP channels here in Switzerland. Buying two transceivers "just in case" seems silly. –  Stu Thompson Apr 4 '11 at 14:24

There is no pure technical reason to install these in pairs, they work perfectly individually.

the reason to install a pair would be redundancy. For instance if you are getting two fibre feeds from your ISP

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Fair enough on the redundancy part, but only if they say that up front. They are telling me it is a requirement. –  Stu Thompson Apr 4 '11 at 12:52

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