System and method for geographic SIP scaling

1. A method for processing a session initiation protocol (SIP) request, comprising:

receiving a SIP request from a user agent (UA) comprising an identifier of a different UA;

obtaining the lookup information of the different UA based on a request to a registrar comprising the identifier;

determining whether the lookup information includes a path header for the different UA, the path header comprising an internet protocol (IP) address of a proxy server related to the different UA; and

generating a routing header for the SIP request based at least in part on whether the lookup information includes said path header for the different UA.

2. The method of claim 1 , wherein generating the routing header comprises including information from the path header in the routing header where the lookup information includes the path header.

3. The method of claim 1 , wherein generating the routing header comprises including information regarding the different UA in the routing header where the lookup information does not include the path header.

4. The method of claim 3 , wherein the information comprises an internet protocol (IP) address of the different UA or a related network address translation (NAT) device received from the registrar in the location information.

5. The method of claim 1 , further comprising:

receiving UA contact information from the UA including at least one of a SIP uniform resource identifier (URI) or an internet protocol (IP) address of the UA; and

transmitting at least a portion of the UA contact information to the registrar for retrieval by other proxy servers.

6. The method of claim 5 , further comprising creating a UA path header that includes the portion of the UA contact information, wherein the transmitting comprises transmitting the UA path header to the registrar.

7. The method of claim 1 , further comprising:

appending the routing header to the SIP request; and

transmitting the SIP request based at least in part on an internet protocol (IP) address in the routing header.

8. The method of claim 7 , wherein obtaining the lookup information comprises obtaining lookup information for a plurality of different UAs related to the identifier, wherein appending comprises appending a plurality of routing headers to a plurality of instances of the SIP request, and wherein transmitting comprises transmitting the plurality of instances of the SIP request to the plurality of different UAs.

9. The method of claim 8 , further comprising:

receiving a response to one of the plurality of instances of the SIP request from one of the plurality of different UAs; and

cancelling one or more of the plurality of instances of the SIP request related to a remaining portion of the plurality of different UAs.

10. A method for processing a session initiation protocol (SIP) request, comprising:

receiving a request for lookup information of a first user agent (UA) from a second proxy server related to a second UA;

determining the lookup information for the first UA based on a path header received from a first proxy server related to the first UA; and

transmitting at least a portion of the lookup information to the first proxy server based on whether the first proxy server is the second proxy server.

11. The method of claim 10 , wherein the transmitting comprises including the path header with the portion of the lookup information where the first proxy server is different from the second proxy server.

12. The method of claim 10 , further comprising removing the path header from the portion of the lookup information where the first proxy server is the second proxy server.

13. A system for processing a session initiation protocol (SIP) request, comprising:

a registrar for receiving a request for lookup information of a first user agent (UA) from a second proxy server related to a second UA; and

a database for storing the lookup information for the first UA based on a path header received from a first proxy server related to the first UA,

wherein the registrar determines the lookup information from the database based at least in part on an identifier of the first UA specified in the request, and transmits at least a portion of the lookup information to the first proxy server based on whether the first proxy server is the second proxy server.

14. The system of claim 13 , wherein the registrar includes the path header in transmitting the portion of the lookup information where the first proxy server is different from the second proxy server.

15. The system of claim 13 , wherein the registrar removes the path header from the portion of the lookup information where the first proxy server is the second proxy server.