Despite the mutual efforts of vendors and users to create interoperability, they still clash, and when they do, it tends to be in the form of a "he said/she said" exchange that doesn't lend itself to clean-cut verdicts of who is right and who is wrong.

For example, John Blackman, a systems architect at a large West Coast-based bank that he declined to identify, takes issue with switch maker McData.

"McData is the worst when it comes to being interoperable," Blackman says. "They don't like interoperability; they want people to stay with them. They will say one thing and do something else. It's to the point where I'm willing to say, 'Screw you, get out of my shop,' but I can't say that politically and because I've got 11,500 ports of their switches in my environment."

Clark says McData isn't unwilling to try to meet Blackman's requirements. "I would say this probably has far less to do with the willingness of McData than it does with the expectation or the timetable being demanded by the customer," he says.

At the edge of his fabric core, Blackman has blade switches from two vendors, QLogic Corp. and McData. He is rankled because in his opinion, the QLogic switch has become "McData-ized."