Patent ID: 8244876

Claim:
A method for use in communications involving a first terminal that is 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 and second messages between the first terminal and the node cause creation of a signaling 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 existing signaling connection through the firewall and network address translator and to thereby maintain the mapping at the firewall and network address translator, wherein failure to repeatedly send the keep-alive messages will result in the existing signaling connection being closed and the mapping being removed; communicating messages, by the first terminal, with the node over the existing signaling connection maintained through the firewall and network address translator to establish a first call session with a second terminal using a first call session connection, the first call session connection being different from the existing signaling connection; and exchanging media packets with the second terminal via the first call session connection.