System and method for providing packet-switched telephony

DETAILED DESCRIPTION It is therefore one object of the present invention to provide a method and system for replacing a circuit-switched network of MSC/VLRs with a packet-switched core network.
It is another object of the present invention to provide a physically decomposed, packet-switched core network for incorporating the voice and data traffic transport and control facilities conventionally provided by networked MSC/VLRs.
The above and other objects are achieved as is now described.
An improved method and system are disclosed for providing packet-switched management of switching and handoff functions for a mobile terminal during call setup and user communication phases of a telecommunication session.
A radio access network (RAN) including an air-interface transceiver in communication with the mobile terminal is in communicative contact with a packet-switched core network including a plurality of heterogeneous functional nodes.
These heterogeneous, scalable nodes in such a core network together provide the functionality that is attributed to multiple MSC/VLRs in a circuit-switched context.
Within the core network are wireless access gateways (WAGs) having media channels that provide an interface between the radio access network and the core network.
A wireless mobility server (WMS) in communicative contact with the WAGs and anchor packet gateways (APGs), serves as a media gateway controller (MGC) for each WAG and each APG, controlling connectivity of the media channels therein.
The WMS also presents the appearance of a single MSC/VLR to the ANSI-41 signaling network, on behalf of other network elements that together provide the functionality of a network of MSC/VLRs.
The WMS and APG together hide the mobility and wireless characteristics of the MT on the control and bearer planes respectively.
A call server (CS) serves as an MGC for trunking media gateways, and its functionality may be derived from an MSC or Class 5 End Office, depending on the service set to be provided to mobile terminals