Twinax trivia check (was Re: Is there such a thing as a 10GBase-T SFP+ transciever)

Jeff Kell jeff-kell at
Sun Feb 2 21:15:55 UTC 2014

On 2/2/2014 4:03 PM, Bryan Tong wrote:
> These cables are most commonly known as "Direct Attach Copper SFP+"

The big issue appears to be that these are not always "consistently
functional" crossing vendor lines (sometimes product lines within the
same vendor).  There does not appear to be any standardization in
place.  Not sure how much of this is picky vendor software looking for
"branded" marks in their transceivers (e.g., Cisco "service
unsupported-transceiver") versus true incompatibilities.

We have had issues in test cases crossing vendor lines (Cisco / Brocade
/ Dell / HP) with a "twinax" link that just simply won't work.  If
anyone has a clear explanation or better understanding, I'm all ears. 
Personal experience comes from only a few testbed cases.


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