System and method for applying authentication and security policies in a SIP environment

1. A SIP (Session Initiation Protocol) server comprising a processor connected to a memory, the processor configured to:

establish a persistent connection between a user agent (UA) and the SIP server;

initiate an idle connection timeout countdown timer subsequent to establishing the persistent connection;

initiate authentication of an initial REGISTER request using a first level of authentication subsequent to initiating the idle connection timeout countdown timer;

terminate the persistent connection when the initial REGISTER request is not authenticated before expiry of the idle connection timeout countdown timer; and

store a new binding for the UA in a registration repository when the initial REGISTER request is authenticated and remove the new binding when the persistent connection is dropped.

2. The SIP server of claim 1 , wherein the processor is further configured to:

receive a subsequent request from the UA over the persistent connection; and

perform authentication of the subsequent request using a second level of authentication, wherein the second level of authentication is lower than the first level of authentication.

3. The SIP server of claim 2 , wherein the second level of authentication comprises minor validation.

4. The SIP server of claim 3 , wherein the minor validation comprises validating at least one of the user name, password, and parameters in the subsequent request.

5. The SIP server of claim 2 , wherein the second level of authentication comprises no authentication.

6. The SIP server of claim 2 wherein the processor is further configured to:

process the subsequent request when the subsequent request is authenticated.

7. The SIP server of claim 6 wherein the processor is further configured to:

reject the subsequent request when the subsequent request is not authenticated.

8. A SIP (Session Initiation Protocol) server comprising a processor connected to a memory, the processor configured to:

establish a persistent connection between a user agent (UA) and the SIP server;

initiate an idle connection timeout countdown timer subsequent to establishing the persistent connection;

initiate authentication of an initial REGISTER request using a first level of authentication subsequent to initiating the idle connection timeout countdown timer;

terminate the persistent connection when an initial REGISTER request is not authenticated before expiry of the idle connection timeout countdown timer;

store a new binding for the UA in a registration repository when the initial REGISTER request is authenticated; and

initiate a keep alive procedure for the persistent connection.

9. The SIP server of claim 8 , wherein the processor is further configured to:

receive a subsequent request from the UA over the persistent connection; and

perform authentication of the subsequent request using a second level of authentication, wherein the second level of authentication is lower than the first level of authentication.

10. The SIP server of claim 9 , wherein the second level of authentication comprises minor validation.

11. The SIP server of claim 10 , wherein the minor validation comprises validating at least one of the user name, password, and parameters in the subsequent request.

12. The SIP server of claim 9 , wherein the second level of authentication comprises no authentication.

13. The SIP server of claim 9 wherein the processor is further configured to:

process the subsequent request when the subsequent request is authenticated.

14. The SIP server of claim 13 wherein the processor is further configured to:

reject the subsequent request when the subsequent request is not authenticated.

15. The SIP server of claim 8 wherein the processor is further configured to:

remove the new binding when the persistent connection is dropped.

16. A non-transitory computer-readable medium storing program instructions that when executed by a processor cause the processor to perform a method for authenticating requests by a SIP (Session Initiation Protocol) server, the method comprising:

establishing a persistent connection between a user agent (UA) and the SIP server;

initiating an idle connection timeout countdown timer subsequent to establishing the persistent connection;

initiating authentication of an initial REGISTER request using a first level of authentication subsequent to initiating the idle connection timeout countdown timer;

terminating the persistent connection when an initial REGISTER request is not authenticated before expiry of the idle connection timeout countdown timer; and

storing a new binding for the UA in a registration repository when the initial REGISTER request is authenticated and removing the new binding when the persistent connection is dropped.

17. A non-transitory computer-readable medium storing program instructions that when executed by a processor cause the processor to perform a method for authenticating requests by a SIP (Session Initiation Protocol) server, the method comprising:

establishing a persistent connection between a user agent (UA) and the SIP server;

initiating an idle connection timeout countdown timer subsequent to establishing the persistent connection;

initiating authentication of an initial REGISTER request using a first level of authentication subsequent to initiating the idle connection timeout countdown timer;

terminating the persistent connection when an initial REGISTER request is not authenticated before expiry of the idle connection timeout countdown timer;

storing a new binding for the UA in a registration repository when the initial REGISTER request is authenticated; and

initiating a keep alive procedure for the persistent connection.