Hi Peter,
I’ve read through the post and have the following comments. Please note that Mellanox does not “lock” out any cable vendors. In other words, the SX1012 switch is open for use with any cable vendor and we do a fair amount of interoperability testing. EMC on the other had does approve specific cables for specific products such as the VNX5200 from my understanding. So, it is likely that when the VNX system reads the EEPROM in the cables you’re using, it doesn’t recognize it as an approved cable and hence doesn’t bring up the link. So, I'm guessing it is a cable issue and not a switch issue. When you purchased the VNX system, did it specify a list of approved cable vendors for this particular product line? Can you please contact your EMC supplier and ask them to provide this? I did a quick web search but couldn't locate this information. Please keep us posted.
Thanks,
Branko.