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How compatible are twinax SFP+ cables when used with different hardware vendors' equipment? E.g. are Cisco SFP+ cables fine between an Arista switch and a Solarflare card? How about an Amphenol cable with Cisco switches and Myricom cards? If in doubt, does it make sense to go with the NIC manufacturer or the switch manufacturer? I've not been able to find any good information either way.

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up vote 5 down vote accepted

It depends on the vendor. Cisco supports Cisco, NetApp, EMC, StorageWorks, IBM and HP passive twinax SFP+ transceivers. If you use a non-certified transceiver the switch will log a warning but still try to bring the port up. This is documented here.

HP used to only work with HP cables. Now it is a mixed bag. We have some HP servers where we had to purchase HP cables to connect them to a Nexxus 5000. We have HP c7000 chassis with virtual connect modules that work similar to the Cisco. They are certified to work with certain vendors but it will work with others while issuing a warning.

The best advice is to check with your vendors to see what is supported with your devices.

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Going with Arista cables for an Arista switch/Myricom NIC combination. – ewwhite May 8 '11 at 4:04

I imagine that this falls into the category of "It'll work but you may have a hard time getting support unless you get both vendors to sign off on the configuration."

That said -- The whole point of SFP / SFP+ / XFP / etc is to prevent vendor lock-in of optics and to allow multi-sourcing of optics for large customers (IE so that AT&T isn't left without a source of transceivers if there is an earthquake in japan that breaks 2 large factories). So the SFP+ is designed to inter-operate, and the CX4 cables are also an IEEE standard, so if it is labeled as such, it should inter-operate.

Sadly, these days, inter-operate and supported aren't synonyms.

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Just ran into this today. Specific to 10G TwinAx - no, EMC does not support passive twinax cables with the VNX. Cisco catalyst 3560/3750 do not support active TwinAx cables. Never the twain shall meet. Cisco Nexus 5000/7000 do support active TwinAx, so this is the way to go.

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Actually there are serial ROMs in the cable ends that include a vendor ID. Some vendors check the ID and disable the ports if you use a cable from a vendor (read competitive source). All this so that they can price gouge for the exact same cable. Same thing you see with SFP+ optics. here's a whole secondary market based on re-writing the vendor ID but this winds up violating copyright law since the vendor proprietary stuff is typically copyrighted. Best advice buy the right cable, less trouble all around.

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Will it work; yes it should (be careful to check revision levels, not all SFP+ are created equal).

Will it be supported if you have 'issues' with the equipment? Probably not, it will depend on the vendor, the nature of the problem, and which way the wind is blowing that day (last one applies to larger vendors mostly).

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