System and method for session initiation protocol header modification

Abstract

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.

What is claimed is: 
     
         1 . A user agent (UA) for communicating with a communications network implementing an internet protocol (IP) multimedia subsystem (IMS), the UA being configured to send and receive session initiation protocol (SIP) messages, the UA comprising:
 a processor, the processor being configured to:
 receive a request for an application policy from a network entity; and 
 send a message to the network entity in response to the request for the application policy, the message identifying an application policy. 
   
     
     
         2 . The UA of  claim 1 , wherein the UA is at least one of a third generation partnership project (3GPP) user equipment, a wireless device, a set-top box, a phone, a computer, and a SIP user agent. 
     
     
         3 . The UA of  claim 1 , wherein the message includes a uniform resource identifier (URI), the URI identifying a location of the application policy within a database. 
     
     
         4 . The UA of  claim 1 , wherein the message contains the application policy. 
     
     
         5 . The UA of  claim 4 , wherein the application policy is encoded using extensible markup language (XML). 
     
     
         6 . The UA of  claim 1 , wherein the message includes at least one of a SIP SUBSCRIBE, a SIP REGISTER, a SIP MESSAGE, a SIP INFO, a SIP OPTION, a SIP PUBLISH, and a SIP REFER request. 
     
     
         7 . The UA of  claim 1 , wherein the message includes a SIP signaling compression (SigComp) transmission. 
     
     
         8 . The UA of  claim 1 , wherein the message includes a message session relay protocol (MSRP) message after a SIP session is established between the UA and a policy provider. 
     
     
         9 . The UA of  claim 1 , wherein the application policy identifies a SIP message header field to remove, and wherein the processor is configured to:
 receive a modified SIP message, wherein the SIP message header field identified by the application policy is not included in the modified SIP message.   
     
     
         10 . The UA of  claim 1 , wherein the application policy identifies a SIP message header field to modify, and wherein the processor is configured to:
 receive a modified SIP message, wherein the SIP message header field identified by the application policy is modified in accordance with the application policy in the modified SIP message.   
     
     
         11 . The UA of  claim 1 , wherein the application policy identifies a SIP message header field to include, and wherein the processor is configured to:
 receive a modified SIP message, wherein the SIP message header field identified by the application policy is included in the modified SIP message.   
     
     
         12 . The UA of  claim 11 , wherein the application policy further identifies an attribute of the at least one of a SIP message header field to include, a SIP message header field to remove, and a SIP message header field to modify, the attribute including 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. 
     
     
         13 . The UA of  claim 1 , wherein the processor is configured to receive, from the network entity, status information of an application of the application policy, 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. 
     
     
         14 . A method of communicating with a communications network implementing an internet protocol (IP) multimedia subsystem (IMS), comprising:
 receiving a request for an application policy from a network entity; and   sending a message to the network entity in response to the request for the application policy, the message identifying an application policy.   
     
     
         15 . The method of  claim 14 , wherein the message includes a uniform resource identifier (URI), the URI identifying a location of the application policy within a database. 
     
     
         16 . The method of  claim 14 , wherein the message contains the application policy. 
     
     
         17 . The method of  claim 14 , wherein the application policy is encoded using extensible markup language (XML). 
     
     
         18 . The method of  claim 14 , wherein the message includes at least one of a SIP SUBSCRIBE, a SIP REGISTER, a SIP MESSAGE, a SIP INFO, a SIP OPTION, a SIP PUBLISH, and a SIP REFER request. 
     
     
         19 . The method of  claim 14 , wherein the message includes a SIP signaling compression (SigComp) transmission. 
     
     
         20 . The method of  claim 14 , wherein the message includes a message session relay protocol (MSRP) message after a SIP session is established between the UA and a policy provider. 
     
     
         21 . The method of  claim 14 , including receiving, from the network entity, status information of an application of the application policy, 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.