cisco-nexusfibersfp
I have my very first Nexus switch to install in our new datacenter. It's a 3172TQ that comes with 4 QSFP+ ports.
All my other devices have SFP+ modules. I did a little research and i found about the QSFP-SFP+ breakout cable.
My question is: Can I plug those four SFP+ cables to different devices or do I need to connect all of them to only one? What are my options here?
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.
You're asking about X2 Optics, which is what the c4948-10GE uses; so the ebay picture you listed is definitely one possible option for the 4948's optics.
Whenever you build optical solutions, remember these basic issues:
LC Connectors:
SC Connectors:
If you're connecting two Cisco switches to each other, turn UDLD on the port to protect against unidirectional cabling.
If you have any problems bringing the link up, loop the transceiver to itself with a loose fiber jumper... this means technically you'd want more than just the LC-SC cable, if you don't already have fiber loopback plugs.
You can build your own MMF LC or SC loopback plug with a piece of LC-LC or SC-SC fiber. Both LC and SC connectors pull apart, and then you just take one of the strands and plug it into the TX and RX of one of the transceivers. If that transceiver lights up, then you've got a good transceiver. Conversely, if the transceiver won't loop up, you need to diagnose why (it could be something as simple as your 10GE port is administratively shutdown).
You've mentioned Cisco-branded parts in your question; however, in case you decide to use 3rd party optics in your Cisco, use these commands.
Switch(config)#service internal
Switch(config)#service unsupported-transceiver
Switch(config)#no errdisable detect cause gbic-invalid
Officially Cisco TAC could bark about this if they see these commands, and occasionally you find a 3rd party pluggable that doesn't work, so YMMV.
Best Answer
Weirdly we've been dealing with these in the last few weeks, they can be tricky buggers. In particular we've been using them from C220 M5's into 5672UP's.
Anyway theoretically you can connect 2, and only 2, of these to one Nexus and the other 2, and again only 2, to another linked Nexus and create a Virtual Port Channel for them but in practice we've had to connect all four to one switch with the second MLOM port going to the second Nexus - that works, so long as you use ALL FOUR ports, fewer aren't supported and port channel them together - oh and you can't use LACP at all.
I'm glad that this is a stop-gap solution as they'll be converted to using regular 40Gbps QSFP cables once the 5696Q switches arrive.