Method and system for providing registration-based SIP NAT traversal

A system for providing network access translation device traversal to facilitate communications, comprising:

• a network access translation (NAT) device;
• a first Session Initiation Protocol (SIP) client located on the interior of the NAT device;
• a second SIP client located on the exterior of the NAT device;
• and
• a proxy server configured to receive registration information relating to the first SIP client and the NAT device over a first communication path through the NAT device, the first communication path terminating at a registration port of the first SIP device,
• wherein the proxy server uses the registration information to initiate contact with the first SIP client on behalf of the second SIP client over the first communication path and to establish a communication session between the first and second SIP clients;
• wherein the communication session bypasses the proxy server and traverses the NAT device such that the first SIP client receives communications from the second SIP client at the registration port.

A proxy server for providing network access translation device traversal to facilitate communications, comprising:

• a lookup table configured to store registration information relating to a first Session Initiation Protocol (SIP) client and a network access translation (NAT) device, the registration information enabling communication with a registration port of the first SIP client over a first communication path through the NAT device;
• and
• control logic configured to use the registration information to allow a second SIP client to initiate contact over the first communication path and establish a communication session with the first SIP client, the second SIP client being located on the exterior of the NAT device and the first SIP client being located on the interior of the NAT device;
• wherein the proxy server assists in the creation of a second communication path through the NAT device for the communication session, the second communication path connecting the registration port of the first SIP client and a port of the second SIP client such that communication between the first and second SIP client bypasses the proxy server.

A method for providing network access translation device traversal to facilitate communications, comprising:

• maintaining registration information relating to a first Session Initiation Protocol (SIP) client and a network access translation (NAT) device on a proxy server, the registration information enabling communication with a registration port of the first SIP client over a first communication path through the NAT device;
• and
• using the registration information to allow a second SIP client to initiate contact and with the first SIP client over the first communication path, the first SIP client being located on the interior of the NAT device, the second SIP client being located on the exterior of the NAT device;
• wherein the second SIP client uses the proxy server to initiate communication with the first SIP client over the first communication path;
• wherein the first SIP client contacts the second SIP client through the NAT device using information sent in a SIP INVITE command from the proxy server, causing a second communication path;
• and
• wherein the second communication path bypasses the proxy server and traverses the NAT device such that the first SIP client receives communications from the second SIP client at the registration port.

A method for providing network access translation device traversal to facilitate communications, comprising:

• directing a network access translation device (NAT) to create a first communication path to a registration port of a recipient SIP client coupled to the NAT device in response to a registration function of the recipient SIP client;
• directing a proxy server to receive an Session Initiation Protocol (SIP) INVITE command issued from an initiating SIP client upon the initiating SIP client wishing the initiate contact and establish a communication session with the recipient SIP client, the initiating SIP client being located on the exterior of the network access translation (NAT) device and the recipient SIP client being located on the interior of the NAT device;
• directing the proxy server to use registration information relating to the recipient SIP client and the NAT device to identify the NAT device and forward the SIP INVITE command to the NAT device over the first communication path;
• upon receipt of the SIP INVITE command, directing the NAT device to use a binding associated with the recipient SIP client to forward the SIP INVITE command to the registration port of the recipient SIP client;
• and
• upon the recipient SIP client accepting the SIP INVITE command, conducting SIP signaling between the registration port of the recipient SIP client and the initiating SIP client, using information contained in the SIP INVITE command, through the NAT device, and causing new binding information to be created.