Method for IP multimedia services session setup

1. In a communication device, a method of establishing existence of quality of service preconditions in a communication network, the method comprising the steps of:

sending an SIP registration request message; and

receiving a registration acknowledgement message having a QOS precondition preference indication; and

sending an invite that includes a quality of service precondition message that corresponds with the QoS precondition preference indication of the registration acknowledgement message.

2. The method of claim 1 , comprising sending an invite that includes a quality of service precondition support message.

3. The method of claim 1 , wherein the quality of service precondition message that corresponds with the QoS precondition preference indication comprises a message indicating that the communication device supports the QoS precondition preference.

4. The method of claim 1 , receiving a network support for resource reservation management and QoS precondition preference in a P-Network-Access-Info header.

5. The method of claim 1 , determining that the network supports the QoS precondition preference and sending the preference for supporting the QoS precondition during a SIP session.

6. The method of claim 1 , determining that the network does not support the QoS precondition during registration initiating a SIP session.

7. In a communication device, a session initiation protocol method comprising the steps of:

sending an SIP registration request message; and

receiving a resource management support message and a QoS precondition preference in a response to the SIP registration request message; and

populating an invite message with a message indicating that the communication device supports the QoS precondition preference.

8. The method of claim 7 , further comprising sending the invite to a packet data session, wherein the message corresponding to the QoS precondition preference comprises a QoS precondition supported message when both the originating network and the terminating network support the QoS precondition.

9. A method for packet data session initiation in a communication device in communication with a network, comprising:

receiving in the communication device from the network a registration request acknowledgement that includes, a QoS precondition preference; and

indicating in the communication device in an invite message during a SIP session that the QoS precondition is to be supported.

10. The method of claim 9 , indicating the QoS precondition supported comprises populating the invite message with a message supported:precondition, 100rel.