System and method for session initiation protocol header modification
A method for modifying the contents of session initiation protocol (SIP) messages is presented. The method includes receiving a SIP message. The SIP message may include a set of message header fields. The method includes receiving an application policy. The application policy may specify how to modify the SIP message based on a characteristic of the SIP message. Alternatively, the application policy may be retrieved from a database such as one provided by a home subscriber server (HSS) or an application server. The method includes using the application policy to modify the SIP message resulting in a modified message, and sending the modified message.
1. A method of operating a network entity in a wireless communications network, comprising:
removing, by an application server, one or more headers from a Session Initiation Protocol (SIP) message, by:
retrieving an application policy from a home subscriber server, the application policy specifying how to modify the SIP message based on a characteristic of the SIP message,
removing via headers from the SIP message, wherein the SIP message comprises a SIP code 200 message corresponding to a SIP Invite message, and
providing status information of an application of the application policy to a user agent, wherein the status information identifies a first portion of the application policy that was successfully applied and a second portion of the application policy that was not successfully applied.
2. The method of claim 1 , wherein the application policy specifies at least one of a SIP message header field to allow, a SIP message header field to remove, a SIP message header field to add, a SIP message header field to allow, and a SIP message header field to modify.
3. The method of claim 1 , wherein the application policy identifies a SIP message header field to modify, and including:
comparing each of a plurality of message header fields in the SIP message to the SIP message header field identified in the application policy; and
when one or more of the plurality of message header fields in the SIP message matches the SIP message header field identified in the application policy, modifying a content of the one or more of the message header fields in the SIP message.
4. The method of claim 1 , wherein the application policy identifies a SIP message header field to allow, and including:
comparing each of a plurality of message header fields in the SIP message to the SIP message header field identified in the application policy; and
when one or more of the plurality of message header fields in the SIP message matches the SIP message header field identified in the application policy, allowing a content of the one or more of the message header fields in the SIP message to be forwarded unmodified.
5. The method of claim 1 , wherein the application policy identifies a SIP message header field to include, and including:
modifying the SIP message to include the SIP message header field identified in the application policy.
6. The method of claim 1 , wherein the application policy identifies an attribute of a SIP message header field, and including:
comparing the attribute of the SIP message header field identified in the application policy to an attribute of one or more of a plurality of message header fields in the SIP message.
7. The method of claim 6 , wherein the attribute identified in the application policy includes at least one of an indication of message direction, an identifier of a service or application, a SIP method name, and a SIP response code.
8. The method of claim 1 , wherein the application policy includes routing application policies.
9. The method of claim 1 , including receiving, from a user agent, a second application policy.
10. The method of claim 9 , wherein the second application policy includes application-specific policies.
11. The method of claim 10 , wherein the second application policy is restricted to mmtel policies.
12. A network entity for modifying session initiation protocol (SIP) headers, the network entity comprising:
a processor, the processor being configured to remove headers from a Session Initiation Protocol (SIP) message by an application server, wherein the processor is configured to remove the headers by:
retrieving an application policy from a home subscriber server,
removing via headers from the SIP message, wherein the SIP message comprises a SIP code 200 message corresponding to a SIP Invite message, and
providing status information of an application of the application policy to a user agent, wherein the status information identifies a first portion of the application policy that was successfully applied and a second portion of the application policy that was not successfully applied.
13. The network entity of claim 12 , wherein the application policy includes routing application policies.
14. The network entity of claim 12 , including receiving, from a user agent, a second application policy.
15. The network entity of claim 14 , wherein the second application policy includes application-specific policies.
16. The network entity of claim 15 , wherein the second application policy is restricted to mmtel policies.