Patent ID: 8144644

Claim:
A method comprising: a radio access network (RAN) receiving an origination message over an air interface from a mobile station, the origination message comprising a code and a called-party identifier, the code indicating that the mobile station is requesting that, on behalf of the mobile station, the RAN set up a packet-based communication session between the mobile station and an endpoint associated with the called-party identifier, wherein the origination message does not comprise a Session Initiation Protocol (SIP) message; and responsive to receiving the origination message from the mobile station, the RAN, on behalf of the mobile station, using a RAN-based SIP client to set up the packet-based communication session between the mobile station and the endpoint, wherein the RAN-based SIP client (i) generates a first SIP message comprising an invitation to the endpoint to participate in the packet-based communication session, (ii) sends the first SIP message to the endpoint, and (iii) receives a second SIP message from the endpoint, the second SIP message comprising an indication that the endpoint has accepted the invitation, wherein, on behalf of the mobile station, the RAN-based SIP client arranges one or more parameters of the packet-based communication session using at least the first and second SIP messages, wherein, responsive to receiving the second SIP message, the RAN-based SIP client sends a third SIP message over the air interface to the mobile station, the third SIP message comprising information enabling the mobile station to engage in at least one of (i) messaging with the endpoint related to the packet-based communication session and (ii) participation in the packet-based communication session with the endpoint, wherein the information comprises the one or more arranged parameters.