What does carrier testing entail?

I have a general understanding on how technology works, I mean I can sideload an Android app to the PlayBook, but when it comes to the 'guts' of a piece of equipment I'm pretty lost.

So when it was announced that the BB10 devices were going to the wireless carriers and have read (on other forums) this generally happens about 5 -6 months before the release of a device.

What makes the testing period so long? I get that the carriers need to test their networks and what not with the device, but what else is involved?

I've never worked for a carrier so I can't be sure, but I can imagine why it takes so long. Besides all the performance benchmarks and whatnot that they'd be looking at in a handset, In Canada for example, a carrier like Rogers has an enormous, enormous network on which they'd want to test the phone from all over and see how it reacts/performs at each of their base stations.

That and I'm sure there's a ton of [Paperwork, red tape, corporate BS, other buzzwords].

They probably check the OS too--what features are available and can make them money :rolleyes:, and if multiple OS versions are available, which one works the best on their network (radio, feature control, etc.)