Fault Tolerance and Load Balancing in QoS Provisioning with Multiple MPLS Paths

Abstract

The paper presents approaches for fault tolerance and load balancing in QoS provisioning using multiple alternate paths. The proposed multiple QoS path computation algorithm searches for maximally disjoint (i.e., minimally overlapped) multiple paths such that the impact of link/node failures becomes significantly reduced, and the use of multiple paths renders QoS services more robust in unreliable network conditions. The algorithm is not limited to finding fully disjoint paths. It also exploits partially disjoint paths by carefully selecting and retaining common links in order to produce more options. Moreover, it offers the benefits of load balancing in normal operating conditions by deploying appropriate call allocation methods according to traffic characteristics. In all cases, all the computed paths must satisfy given multiple QoS constraints. Simulation experiments with IP Telephony service illustrate the fault tolerance and load balancing features of the proposed scheme.