Efficient routing of information between interconnected cellular mobile switching centers

At the switch boundaries of cellular systems, it is necessary to provide an inter-switch handover procedure if calls are to remain in progress as users cross these boundaries. Both the North American and Pan European second generation standards provide mechanisms for inter-switch handover. Motivated by the need to develop procedures for inter-switch handover in the cellular packet switch (CPS), this paper develops a general set of procedures for inter-switch handover that, unlike their second generation counterparts, provide a mechanism for the transport of data. Unlike voice, data packets must all be delivered. The delivery may need to be sequential and/or restricted to a single copy. The path optimization procedures are all presented in the context of the CPS. In addition, we identify capabilities needed by the CPS and present suitable protocols. The path optimization procedures are evaluated based on the following performance criteria: guarantee of sequential delivery, avoidance of multiple copies, and delay. Fundamental limitations on data throughput result if both sequential delivery and a single copy are required.