Maintaining stable virtual circuit data connections with spare protocol handler
First Claim
1. A method of maintaining stable virtual circuit connections, each connection controlled by one serving protocol handler (PH) of a group of PHs, said group comprising a spare PH, said method comprising:
- whenever a virtual circuit connection reaches a stable state, storing state information for said connection in a predetermined PH of said group, said predetermined PH being adjacent to said serving PH;
in the event of failure of said serving PH, serving stable connections of said failed serving PH in the predetermined adjacent PH; and
serving new connections destined for service by said failed serving PH in said spare PH which takes the role of said failed serving PH, said spare PH different from the predetermined adjacent PH.
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Accused Products
Abstract
This invention relates to apparatus and methods for providing cellular mobile telecommunication service in accordance with the requirements of the Global Systems for Mobile Communications (GSM) standard. A modular switching system is provided which performs the functions of the mobile switching center plus those of a home location register, authentication center, visitor location register, and equipment identity register. The latter functions are advantageously spread among the modules of the switching system, thus avoiding the getting started cost of expensive dedicated data bases. A wireless global switching module advantageously switches mobile communications control messages among the modules of the system and between the modules and the base station systems, and terminates signaling links between the mobile switching center and the base station systems. Arrangements are provided for maintaining stable virtual circuit connections in this module even in the presence of protocol handler failures. The state of each virtual circuit is kept in a protocol handler (PH) controlling the circuit and, whenever a stable state is reached, notifying an adjacent PH; if the controlling PH fails, the adjacent PH takes over control of that virtual circuit for immediate purposes, and a spare PH serves any new requests that would normally be served by the failed PH. The spare PH transmits messages, originally destined to the failed PH, to the adjacent PH for those virtual circuits already in use at the time of the failure and being served by the adjacent PH.
43 Citations
12 Claims
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1. A method of maintaining stable virtual circuit connections, each connection controlled by one serving protocol handler (PH) of a group of PHs, said group comprising a spare PH, said method comprising:
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whenever a virtual circuit connection reaches a stable state, storing state information for said connection in a predetermined PH of said group, said predetermined PH being adjacent to said serving PH; in the event of failure of said serving PH, serving stable connections of said failed serving PH in the predetermined adjacent PH; and serving new connections destined for service by said failed serving PH in said spare PH which takes the role of said failed serving PH, said spare PH different from the predetermined adjacent PH. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for maintaining stable virtual circuit connections comprising:
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an interconnected group of protocol handlers (PHs), said group comprising a spare PH, connectable to message sources and destinations, each for storing state information for stable virtual circuit connections in a predetermined adjacent PH of said group; means for connecting said spare PH, said spare PH different from said predetermined adjacent PH, to message sources and destinations of a failed serving PH; said predetermined adjacent PH for serving connections for messages already active at a time when said serving PH failed; and said spare PH for transmitting to said predetermined adjacent PH messages of virtual circuit connections originally served by said failed serving PH. - View Dependent Claims (11, 12)
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Specification