It's an open protocol and there are open source implementations of the technology. I can use asterisk to set up a phone system and have numbers routed to me fro

It's an open protocol and there are open source implementations of the technology. I can use asterisk to set up a phone system and have numbers routed to me from a provider. It's the same as the Internet in that regard. It's like saying email isn't open source because it has to have a connection to the Internet to be useful.