Optimizing capacity assignment in multiservice MPLS net-works

Abstract: The general Multiprotocol Label Switch (MPLS) topology optimisation problem is complex and concerns the optimum selection of links, the assignment of capacities to these links and the routing requirements on these links. Ideally, all these are jointly optimised, leading to a minimum cost network which continually meets given objectives on network delay and throughput. In practice, these problems are often dealt with separately and a solution iterated. In this paper, we propose an algorithm that computes the shortest routes, assigns optimal flows to these routes and simultaneously determines optimal link capacities. We take into account the dynamic adaptation of optimal link capacities by considering the same Quality of Service (QoS) measure used in the flow assignment problem in combination with a blocking model for describing call admission controls (CAC) in multiservice broadband telecommunication networks. The main goal is to achieve statistical multiplexing advantages with multiple traffic and QoS classes of connections that share a common trunk present. We offer a mathematical programming model of the problem and proficient solutions which are founded on a Lagrangean relaxation of the problem. Experimental findings on 2-class and 6-class models are reported

High Level B-ISDN/ATM Traffic Management in Real Time

We study real time traffic management in the perspective of a four-level model of traffic variations: cells, bursts, sessions, and links. Our interest is focused on the two latter levels: Using virtual channels (VCs) and virtual paths (VPs) as the managed entities on the two levels respectively, we put forward a simple and robust strategy for traffic management in real time: All nodes simultaneously monitor offered traffics and forward the result to a network management centre (NMC); The NMC computes a new set of optimal VPs and compares the result to the existing network; If a change appears profitable, the necessary information is sent back to the nodes and the new design is implemented. Applying our strategy to control general networks subject to traffics which in advance are known only as expectations, we develop simple methods for traffic observation, the optimal observation interval, a fast and efficient algorithm to compute VP networks, a test to determine whether to implement a new design in which costs related to lost traffic are compared to processing costs, and the optimal updating interval. Running our strategy in a simulator, we discover a considerable adaptivity, large savings in transmission capacity, and a performance far better than achieved by fixed redesign according to forecasts. Finally we discuss limits to the range of variations within which our strategy can be applied. The present work applies both to networks using SDH/SONET and/or networks based on ATM, i.e. both to present public switched telephony networks and broadband inte- grated services digital networks, and is a summary and extension of earlier works within this area [3{9].This article is written under the Project "VP and VC Assignment and Routing

High Level B-ISDN/ATM Traffic Management in Real Time

We study real time traffic management in the perspective of a four-level model of traffic variations: cells, bursts, sessions, and links. Our interest is focused on the two latter levels: Using virtual channels (VCs) and virtual paths (VPs) as the managed entities on the two levels respectively, we put forward a simple and robust strategy for traffic management in real time: All nodes simultaneously monitor offered traffics and forward the result to a network management centre (NMC); The NMC computes a new set of optimal VPs and compares the result to the existing network; If a change appears profitable, the necessary information is sent back to the nodes and the new design is implemented. Applying our strategy to control general networks subject to traffics which in advance are known only as expectations, we develop simple methods for traffic observation, the optimal observation interval, a fast and efficient algorithm to compute VP networks, a test to determine whether to implement a new design in which costs related to lost traffic are compared to processing costs, and the optimal updating interval. Running our strategy in a simulator, we discover a considerable adaptivity, large savings in transmission capacity, and a performance far better than achieved by fixed redesign according to forecasts. Finally we discuss limits to the range of variations within which our strategy can be applied. The present work applies both to networks using SDH/SONET and/or networks based on ATM, i.e. both to present public switched telephony networks and broadband inte- grated services digital networks, and is a summary and extension of earlier works within this area [3{9]