Design, Implementation, and Performance of a Cluster Mobile Switching Center

In this paper, we present the design and implementation of a software system that performs the control functions of current Mobile Switching Centers (MSCs) and Visitor Location Registers (VLRs), and provides support for third generation services. The novelty of the system design is in its software architecture. To allow flexible deployment of the system as the migration from second generation to third generation systems occurs, the software is modular. To provide scalability in terms of capacity, distributed processing is used. This type of system design is becoming increasingly more desirable and common as commodity processor prices drop and large capacity switches are demanded. One serious concern with these approaches is whether the required performance of the target switching systems can be met. We show that a deployment of this system using three Sun Ultra workstations achieves a call throughput of 300,000 calls/hour with a latency of below 300 milliseconds. This meets the latency requirements of third generation systems.