I would like to learn more about protocol state machines. Can someone point me to some resources other than the standard itself? I found a presentation from NASA which was a good start and gave me a general idea of the differences. I would like to see some more examples.
I don't know of much published literature on it; it's not widely used. The idea is to defined when services are available for invocation. Protocol state machines are not allowed to have implementation, as I recall.