Service triggering algorithm for optimal load balancing in heterogeneous multiple AS (Application Server) system

In this paper, we propose a load balancing scheme for heterogeneous multiple AS (Application Server) system in IMS (IP Multimedia Subsystem) network. In IMS network, S-CSCF (Serving Call Session Control Function) utilizes iFC(initial Filter Criterion) downloaded by HSS(Home Subscriber Server) and generates service trigger through the SIP message. To perform load balancing among multiple AS with different structure, weight value for service trigger should be set. In previous system, the weight value should be set manually by the operator. In this paper we propose a method to calculate optimal weight for load balancing in automatic manner. We also propose simplified algorithm to reduce calculation in specific situation. Through simulation result, we verify that our proposing scheme outperforms previous schemes in load balancing and adjusts well to the change of the system in automatic manner with fast convergence.