aging the overall session status and connection establishments. C 2009 by Taylor & Francis Group, LLC Q-SIP/SDP for Converged Heterogeneous Wired and Wireless Networks 357 TABLE 15.2 Functionality of RSVP-TE Messages RSVP-TE Message Description Major Contents Used to set up and maintain SENDER_TEMPLATE reservations SENDER.TSPEC, ADSPEC Sent in response to PATH FLOWSPEC, messages to set up and FILTER_SPEC maintain reservations RESV-Conf Optionally sent back to the FLOWSPEC, sender of a RESV message to FILTER_SPEC, confirm that a given ERROR_SPEC reservation actually got installed PATH-Error Sent by a recipient of a PATH ERROR_SPEC, message who detects an error POLICY_DATA in that message RESV-Error Sent by a recipient of a RESV ERROR_SPEC, message who detects an error POLICY DATA in that message PATH-Teardown Analogous to PATH messages, SENDER_TSPEC, but used to remove ADSPEC reservations from the network RESV-Teardown Analogous to RESV messages, FILTER_SPEC but used to remove reservations from the network A PATH message is delivered to the destination, and the destination termi- nal sends a RESV message to request the resource reservation and connection establishment. Since Q-SIP/SDP has been used to configure the bidirectional session, the PATH/RESV message exchange is executed for each direction. We assume that the QoS-parameters are defined in the service level agreement (SLA)/service level specification (SLS), and traffic engineered label switched paths (TE-LSPs) are established among Provider Edge (PE) pairs for sim- plified traffic grooming. A multimedia application may require the multiple QoS-guaranteed connections for multiple media streams. Since the RSVP-TE is using "soft state" connection management [11], the end user's terminal should periodically exchange the PATH and RESV mes- sage to keep the connection in normal operational mode. When the required network resource is changed for the multimedia session, the traffic parame- ters of the connection must also be updated by the PATH/RESV message exchan