A key selling point for storage vendors transitioning from 2-Gbit/s to 4-Gbit/s Fibre Channel gear is backward compatibility. Customers can just replace one set of equipment with another, and everything is guaranteed to work just fine, right?
Maybe not, according to one of the key testers of 4-Gbit/s products. David Woolf, manager of the University of New Hampshire InterOperability Laboratory (UNH-IOL)-Fibre Channel Consortium, says neither vendors nor customers should take it for granted that everything will work without a hitch after a 4-Gbit/s upgrade.
Theres still work to be done, Woolf says. The leap is not trivial. I think 4-gig as a technology makes sense, and it is a technology that will work. But the products are brand new. People say, Its just like 1- or 2-gig, were just adding another speed. Its a small change, it shouldnt create any problems. But people are creating new products. You dont want to get caught up in just a little change, and not do the testing.
Woolf advocates more testing on two fronts. He would like to see a third 4-Gbit/s plugfest (there have already been two, this past January and then again im May), and he might get his wish later this year. He also thinks 4-Gbit/s equipment could benefit from conformance testing.
Conformance testing tools create data patterns, modify data, insert data errors, and generate traffic to match standard 4-Gbit/s FC patterns, while sending frames within a fabric or arbitrated loop connection. Then they evaluate the devices responses and analyze performance.