Patent ID: 8484359

Claim:
A method for communications involving a first terminal coupled to a first side of a firewall and network address translator, the method comprising: sending, by the first terminal, a first message identifying the first terminal to a node on a second side of the firewall and network address translator, the first message identifying the first terminal as available for a call session; receiving, by the first terminal, a second message from the node, wherein the first message and the second message cause creation of a signalling connection through the firewall and network address translator and creation of a mapping between a first address of the first terminal and a second address of the first terminal, where the first address is an address assigned to the first terminal on the first side of the firewall and network address translator, and where the second address is an address assigned to the first terminal on the second side of the firewall and network address translator; repeatedly sending keep-alive messages to maintain the mapping at the firewall and network address translator; communicating messages, by the first terminal through the firewall and network address translator using the mapping maintained at the firewall and network address translator, to establish a first call communication session with a second terminal using a first call communication session connection; and exchanging media packets with the second terminal via the first call communication session connection.