Probabilistic Selection of QoS Paths for Improving Survivability in MPLS Networks

Many applications do not fit well with the traditional best effort packet delivery policy of the Internet. These include applications such as Internet telephony and video conferencing which require voice and bulky graphical images transfer. Therefore, the policies of assigning traffic to various service classes and providing service as per the service level agreement of the user with the network provider came into existence. Multi-protocol Label Switching is the backbone of fast switching technology that helps the network service providers to implement these policies. It provides Quality of service oriented reserved paths from the source to the destination for the user’s traffic. Selection of these paths is a cumbersome task, especially when the traffic forecast is totally unknown. Furthermore, nodes and link failures in the Internet worsen the situation. This paper addresses the issue of selecting Label Switched Paths (LSPs) for various traffic demands in the network so that the resultant network has the characteristics like high failure resistance, low LSP demand blocking probability, low impact from the node or link failure, load balancing and low over-all resource utilization. By extensive simulations, the proposed cost function has been compared with the various cost functions mentioned in the literature and it was found to score over them in major aspects.