Any downside to using Twinax instead of fiber?

[poulid]

Hello. We bought a pair of 4500X's, and will be running them in VSS mode. I was wondering if there was any downside to using Twinax cables for both the VSL links, as well as the uplinks into a WS-X6816-10G line card (with the OneX converters). 

The only downside I can find is distance, which won't be a problem since the switches are all sitting in the same LAN rack. The cost of the Twinax solution is approx 15% of the cost of doing it with SFP+ modules and fiber...am I missing something?

I've checked with TAC, and everything is compatible.

[Joseph W. Doherty · Accepted solution]

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Posting

In theory fiber is "better" because of its immunity to EM interference and often it supports "better" fault detection.

I haven't worked with Twinax, but I've commonly used copper gig for infrastructure connections (when within spec for media), when many of my peers propose using fiber, because fiber is "always" used for infrastructure connections.

I don't recall, in the last decade and a half, of any issues caused by not using fiber, when I could have, beyond it often being easier on the budget.  ;)

I would expect Twinax might work just find for you, but it will be interesting to see what other experience others have had.

[Brad Martin · Accepted solution]

We have been using twinax connections between pairs of Nexus 7K and to top of rack Nexus 2K's for some time and have had no issues.

[Masoud Pourshabanian]

Hello,

You can use passive Twinax if the distance between two switches are up to 5 meters and active Twinax if the distance is up to 10 meters. There is no major downside for using Twinax in short distances except signal interference.

Masoud

[Mark Malone]

Haven't used twinax on VSS , we ran out of fibre though on a large DC upgrade recently rolling out load of 2k switches , ended up using twinax for the last few 2ks to connect back to the 5ks, Cisco had sent them over box of them free as we had large order

so far haven't seen any issues compared to fibre cables but we only have minimal servers connected so it will be interesting to see when the load fills is there any difference with fibre but so far so good haven't seen anything out of the ordinary

if I was putting in more I would use twinax the price of the sfps an fibre is to much to justify unless I can find a reason not too , maybe as Joseph said others may have had issues were not aware of yet would b good to hear of they did

Just so your aware too I had 15metre twinax cables so you should be able to get longer if required as mime go cab-cab in the DC