Howard Marks, who blogs for deepstorage.net and Network Computing, recently exposed the reality that some 10-Gbit/sec switches will function properly only if the cabling plugged into them is a specific brand. Generally, that brand is their own. As the name of Marks's site suggests, he is talking about storage networks within data centers.
In a post dated December 1, Marks explained, "As I brought my Brocade 8000 switch up and started using it, I've had a few hiccups that led me to believe things weren't as simple as I hoped. Frankly, vendors are at fault. 10-Gbps twinax Direct Attach Copper (DAC) cables seemed to be the answeer. When Brocade so kindly lent me the switch, it provided two Brocade-branded cables and a handful of 10G-SR optics. Not wanting to be a piker, I ordered additional cables from Amphenol Cables on Demand ...
"When I tried using the cables, the switch said they were invalid SFPs. A little research ... showed that Brocade supports only active DAC. I had bought passive. ... I then read the Brocade 8000 FAQ, which says that the 8000 supports only Brocade-branded SFPs. I read this to mean that if I bought Molex active cables - which by the way are what Brocade sells, although Brocade has Molex change the identifier to Brocade - they wouldn't work, either."
His blog further says that other equipment "will make a best effort with whatever you plug into them," but still others will go as far as crashing if the wrong active cable is plugged into them.
His follow-up, posted here at Network Computing on December 15, was entitled "The Cable Conundrum Continues - Vendors Respond." It is based on Marks's pursuit of the issue through which he asked 10-Gbit networking vendors about their support of active and passive direct-attach copper cables. As he points out in the post, Cisco provided an interesting response: "'At Cisco, we have a very straightforward view on cables - we're against them! Specifically, we believe that data centers should deploy as few cables as possible.'" For his part, Marks commented, "This is a sentiment I can agree with completely."