Method for delivering device and server capabilities

1. A method comprising:

generating a session initiation protocol ‘SIP’ OPTIONS message at a push receiver agent, the SIP OPTIONS message configured to deliver the push receiver agent's capability to a push sender agent;

including a contact header in the SIP OPTIONS message, the contact header including a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent;

including an allow header in the SIP OPTIONS message, the allow header including SIP methods supported by the push receiver agent;

sending the SIP OPTIONS message that includes: a) the contact header with the push resource identifier feature tag containing the value of the push resource supported by the push receiver agent; and b) the allow header with the SIP methods supported by the push receiver agent to provide the push receiver agent's capability to the push sender agent; and

receiving, relative to sending the SIP OPTIONS message, a SIP 200 OK response that includes: a) a contact header including a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent which was specified in the SIP OPTIONS message; and b) an allow header containing SIP methods that the push sender agent supports.

2. The method of claim 1 wherein the contact header of the SIP OPTIONS message further includes a uniform resource identifier ‘URI’ identifying the push receiver agent.

3. The method of claim 2 wherein the URI is a globally routable user agent ‘UA’ URI ‘GRUU’.

4. The method of claim 1 wherein the SIP methods supported by the push receiver agent include at least one of INVITE, ACK, CANCEL, OPTIONS, BYE and MESSAGE.

5. The method of claim 1 further comprising:

including a user agent header in the SIP OPTIONS message, the user agent header containing at least one of a model, vendor and version of the push receiver agent.

6. A non-transitory computer-readable medium containing instructions which, when executed by a processor, are configured to cause performance of the method of claim 1 .

7. A device comprising:

a processor configured to execute a push receiver agent for:

generating a session initiation protocol ‘SIP’ OPTIONS message configured to deliver the push receiver agent's capability to a push sender agent;

including a contact header in the SIP OPTIONS message, the contact header including a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent; and

including an allow header in the SIP OPTIONS message, the allow header including SIP methods supported by the push receiver agent; and

a communication portion configured for:

sending the SIP OPTIONS message that includes: a) the contact header with the push resource identifier feature tag containing the value of the push resource supported by the push receiver agent; and b) the allow header with the SIP methods supported by the push receiver agent to provide the push receiver agent's capability to the push sender agent; and

receiving, relative to sending the SIP OPTIONS message, a SIP 200 OK response that includes: a) a contact header including a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent which was specified in the SIP OPTIONS message; and b) an allow header containing SIP methods that the push sender agent supports.

8. The device of claim 7 wherein the contact header of the SIP OPTIONS message further includes a uniform resource identifier ‘URI’ identifying the push receiver agent.

9. The device of claim 8 wherein the URI is a globally routable user agent ‘UA’ URI ‘GRUU’.

10. The device of claim 7 wherein the SIP methods supported by the push receiver agent include at least one of INVITE, ACK, CANCEL, OPTIONS, BYE and MESSAGE.

11. The device of claim 7 wherein the processor is configured to execute a push receiver agent for further including a user agent header in the SIP OPTIONS message, the user agent header containing at least one of a model, vendor and version of the push receiver agent.

12. A method comprising:

receiving, at a push sender agent, a SIP OPTIONS request configured to deliver a push receiver agent's capability to the push sender agent, the SIP OPTIONS request including: a) a contact header with a push resource identifier feature tag containing a value of a push resource supported by a push receiver agent; and b) an allow header with SIP methods supported by the push receiver agent;

generating, at the push sender agent, a SIP 200 OK message in response to the SIP OPTIONS request;

including a contact header in the SIP 200 OK message, the contact header including a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent which was specified in the SIP OPTIONS request; and

including an allow header in the SIP 200 OK message, the allow header containing SIP methods that the push sender agent supports.

13. The method of claim 12 further comprising:

including an accept header in the SIP 200 OK message, the accept header containing a MIME type supported by the push sender agent.

14. The method of claim 13 wherein the MIME type supported by the push sender agent is “message/external-body”.

15. The method of claim 12 further comprising sending the SIP 200 OK message after the including operations.

16. A non-transitory computer-readable medium containing instructions which, when executed by a processor, are configured to cause performance of the method of claim 12 .

17. A device comprising:

a processor configured to execute a push sender agent; and

a communication portion configured for receiving a SIP OPTIONS request configured to deliver a push receiver agent's capability to the push sender agent, the SIP OPTIONS request including: a) a contact header with a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent; and b) an allow header with SIP methods supported by the push receiver agent to provide the push receiver agent's capability to the push sender agent;

the processor being configured to execute the push sender agent for:

generating a SIP 200 OK message in response to the SIP OPTIONS request;

including a contact header in the SIP 200 OK message, the contact header including a push resource identifier feature tag containing a value of a push resource supported by the push receiver agent which was specified in the SIP OPTIONS request; and

including an allow header in the SIP 200 OK message, the allow header containing SIP methods that the push sender agent supports.

18. The device of claim 17 wherein the processor is configured to execute the push sender agent for further including an accept header in the SIP 200 OK message, the accept header containing a MIME type supported by the push sender agent.

19. The device of claim 18 wherein the MIME type supported by the push sender agent is “message/external-body”.

20. The device of claim 17 wherein the communication portion is further configured for sending the SIP 200 OK message after the including operations.