Bandwidth constraint models: a performance study

Paper presented at IEEE GLOBECOM 2006 - 2006 Global Telecommunications Conference. San Francisco, CA: pp. 4150664.Bandwidth constraint models have been a topic of intense discussions at the IETF meetings. Three conventional methods have been described in informational IETF RFCs and their performance on a single link has been analyzed and discussed in the literature. In this article, we take a further step into analyzing their performance and optimal bandwidth constraint setting for a real network scenario. A new model is proposed and compared to existing ones when failure events may cause preemption of traffic trunks in a network. Our simulations results provide great insight on the benefits of the methods

New techniques for end-to-end quality of service provisioning in DiffServ/MPLS networks

Ph.D.Ian F. Akyildi

Path-computation-element-based architecture for interdomain MPLS/GMPLS traffic engineering: overview and performance

IEEE Network, 21(4): pp. 38-45.The Path Computation Element Working Group at the Internet Engineering Task Force is chartered to specify a PCE-based architecture for the path computation of interdomain MPLS- and GMPLS-based traffic engineered label switched paths. In this architecture, path computation does not occur at the head-end LSR, but on another path computation entity that may not be physically located on the headend LSR. This method is greatly different from the traditional “per-domain” approach to path computation. This article presents analysis and results that compare performance of the PCE architecture with the current state-of-the-art approach. Detailed simulations are undertaken on varied and realistic scenarios where preliminary results show several performance benefits from the deployment of PCE. To provide a complete overview of significant development taking place in this area, milestones and progress at the IETF PCE WG are also discussed

G+: enhanced traffic grooming in WDM mesh networks using lighttours

IEEE Journal on Selected Areas in Communications, 25(5): pp. 1034-1047.In this article, a new technique for grooming low-speed traffic demands into high-speed optical routes is proposed. This enhancement allows a transparent Wavelength- Routing Switch (WRS) to aggregate traffic en route over existing optical routes without incurring expensive Optical-Electrical- Optical (OEO) conversions. This implies that: a) an optical route may be considered as having more than one ingress node (all inline) and, b) traffic demands can partially use optical routes to reach their destination. The proposed optical routes are named “lighttours” since the traffic originating from different sources can be forwarded together in a single optical route, i.e., as taking a “tour” over different sources towards the same destination. The possibility of creating lighttours is the consequence of a novel WRS architecture proposed in this article, named “Enhanced Grooming” (G+). The ability to groom more traffic in the middle of a lighttour is achieved with the support of a simple optical device named λ-monitor (previously introduced in the RingO project). In this article, we present the new WRS architecture and its advantages. To compare the advantages of lighttours with respect to classical lightpaths, an Integer Linear Programming (ILP) model is proposed for the well-known multilayer problem: Traffic Grooming, Routing and Wavelength Assignment. The ILP model may be used for several objectives. However, this article focuses on two objectives: maximizing the network throughput, and minimizing the number of Optical-Electro-Optical conversions used. Experiments show that G+ can route all the traffic using only half of the total OEO conversions needed by classical grooming. An heuristic is also proposed, aiming at achieving near optimal results in polynomial time