o the QoS broker, stored in its profile. The user service profile consists of terminal/service pairs, suited for Diffserv QoS signalling. QoS on the Core and Access Networks The core network, like the access network, is actually managed per aggregate of network services and not by user services. Packets that need to be transmitted should cross all the domains and the various core network resources are then distributed between the various classes of service according to different traffic levels. The access network is managed by a specific entity called the QoS broker and their numbers may vary in a domain. The QoS broker basically: provides an interface between the user service view and the effective QoS support at the network level; manages and monitors the access network resources (both the ARs and radio gateways (RGs)); monitors the internetwork edges for incoming and outgoing resource reservations/utilisations; can perform SAC (service admission control) decisions and does network device configurations as instructed by the network administration entities; is responsible for maintaining interdomain communications with neighbour QoS brokers. All-IP Network User and Session Signalling There is a DSCP code defined for every service and SO every packet being transmitted contains appropriate information required by network entities to account, authenticate, forward and differentiate each packet and each service/user. After registering, the user signals by sending a DSCP code of the service that he/she intends to use. The QoS broker recognises the code and if there are available resources for the requested service then the packets will be forwarded and accounted for; otherwise the AR informs the user/terminal. For termination, a timeout is associated with every network service. If no packets belonging to that service are sent or received for this timeout period then the network elements will free those resources. Services Network Services These are unidirectional or bidirectional services provided by the Diffserv arc