Nortel Networks Corporation

Rockstar Consortium US LP

Stephen R Kolski

Stewart Hodde Maxwell

Paul Boudreaux

Patrick N Sollee

Nhut Nguyen

In a bearer-independent core network, the switching and transport of the bearer streams is separated from the processing of call sessions that control the bearer streams. The switching and transport of the bearer streams is executed by media gateways and packet switches in the switching and transport layer of the network. The processing of calls sessions that control the bearer streams is executed by call servers in the call control layer of the network. The switching and transport layer of the network may be implemented using ATM or IP technology. In order to redirect the signaling links to a backup call server, a signaling gateway is used. Each media gateway includes a signaling gateway function. The signaling gateways redirect the signaling links by encapsulating each signaling message in a new packet in one embodiment.

Geographic redundancy for call servers in a cellular system based on a bearer-independent core network

A wireless communication system includes at least one mobile switching center ('MSC'), at least one base station coupled to each MSC, a visitor location register ('VLR') and a visitor location register manager ('VLRM'). Each MSC couples to at least one base system controller ('BSC') which couples to at least one base transceiver station ('BTS'). Each BTS provides wireless communication within at least one respective cell, each of the plurality of mobile terminals communicating through a corresponding BTS, BSC and MSC when resident within a cell. The VLR corresponds to one of the MSCs and stores subscriber information for mobile terminals that are active in corresponding cells. The VLRM downloads, from a home location register, subscriber information for mobile terminals becoming active within one of a plurality of cells corresponding to the VLR and stores the subscriber information as a VLR record in the VLR. In accordance with the present invention, the VLRM selectively retains VLR records when corresponding mobile terminals becomes inactive within the cells corresponding to the VLR. The VLRM organizes the VLR records based upon a selected priority. In one embodiment, the VLR is organized as a linked list based upon the priority of VLR records. Stored on the basis of priority, the VLRM may delete VLR records on the same priority basis. In one embodiment of the present invention, a selected priority relates to the time stamp of last activity within any cell respective to the VLR.

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Plano, TX, United States of America

Stephen R Kolski