Patent ID: 7610037

Claim:
A method, comprising: putting, in response to an invitation message, on hold a communication session between a user equipment associated with a first access network and a node of a communication system via a second network and at least one entity of said communication system between said user equipment and said node, the communication session established without preconditions to reserve resources for the communication session when the preconditions are not supported on the communication session between the user equipment and the node, the communication session established based on a session initiation protocol (SIP) and session data protocol (SDP); reserving resources for said session while said session is on hold; communicating a charging identifier from a node of said first access network to a first node of said second network; and resuming, in response to sending another invitation message and when the resources have been reserved, said communication session with the another message indicating an active session from said user equipment by which said charging identifier for the first access network is forwarded from said first node of the second network to a second node of the second network, wherein the first access network is different from the second network.