Admission control in Flow-Aware Multi-Topology Adaptive Routing

Flow-Aware Multi-Topology Adaptive Routing (FAMTAR) is a new mechanism which provides the ability to use multiple paths between two points in a network. When the primary path becomes congested, a new path is found and used. However, when all possible paths are congested, new flows are still accepted on one of the congested paths which degrades the observed quality of service. Therefore, in this paper, two admission control mechanisms for FAMTAR are presented and analyzed. The main goal of the algorithms is to restrict new flows´ access to congested paths and force them to wait for resources to become available. We propose two different methods to determine whether an available path for a new flow is congested or not. Moreover, we propose a mechanism which assures the transmission of selected flows (e.g. emergency calls) through paths with minimum total delay. The presented analysis shows the advantages of the introduced proposals and allows to estimate the potential gain from using these mechanisms.