Why they say bitcoin has its own protocol?

[BlackHatCoiner]

Why do they? I haven't researched this too much but read my query.

You connect with every node with the IP protocol plus a port. Why do we count that as a different protocol? If it had its own shouldn't the nodes create their own "IP addresses"? But then wouldn't it work with internet access but with its own "internet".

Confused... 

[pooya87]

your question is not clear.
the IP address is assigned to you by your ISP, you can't set it yourself. and bitcoin protocol has a section on P2P protocol which defines the communication protocol that is used by bitcoin nodes that defines the messages, handshake process, and things like that.