Load Sharing in a Distributed IMS Architecture

The IP Multimedia Subsystem (IMS) serves as universal platform for fast and standardized creation of mobile services. Typical deployment models for the IMS favor centralized session control and application servers. Furthermore, they rely on sophisticated border elements for, e.g., policy enforcement. One step towards a simpler architecture is the integration of call control, application server, and media functions into border elements. This leads to a distributed IMS architecture with equal processing nodes, which drastically reduces system complexity and scales on functional module instantiation basis. However, the distributed nature of the architecture reduces the statistical gain. In this work, we study a suitable load sharing concept that counters or even over-compensates this problem. In principle, this mechanism realizes one large virtual central server with small control and message overhead. Our simulative evaluation shows the feasibility and performance of our approach.