UMTS Packet Service Infrastructure: Distributed Is Cheaper

In a UMTS network, packet services are provided by transporting traffic between the Radio Access Network and the UMTS Core Network. UMTS packet data traffic terminates at GGSNs that extract packets and routes them to and from the service provider's data centers and/or public data network POIs. This GGSN functionality and POI access can be provided either at a centralized location or at multiple locations distributed throughout the provider's network, thus representing a tradeoff between recurring costs (transport, OA&M) and capital costs (GGSNs, data servers and caches). We consider this optimization problem at three levels. First, assuming uniformly distributed users in a greenfield scenario, we characterize the optimal level of decentralization and its dependence on the ratio of key cost parameters. Second, we assume a pre-specified core network and relate the optimization to the p-median location problem. Finally, we consider a scenario involving a choice between a single centralized node and a fixed set of regional nodes. In each case, we give results for specific examples. We gind that in the current cost environment, a distributed architecture provides a dramatic reduction in overall cost.