How do they relate? They don’t. They must all be interworked into each other in order to define the media path. SS7 controls pstn networks, which can then go to a voice over IP gateway which can use any of the IP based protocols. How do they interwork? That would depend on the who built the box. Most still have to figure out how to get SS7 transparency in order to pass the necessary fields through to the far end pstn. I could go on for days but am running out of time. If you have specific questions please post