A meta-model for multiobjective routing in MPLS networks

Abstract

MPLS (Multiprotocol Label Switching) enables the utilisation of explicit routes and other advanced routing mechanisms in multiservice packet networks, capable of dealing with multiple and heterogeneous QoS (Quality of Service) parameters. Firstly the paper presents a discussion of conceptual and methodological issues raised by multiobjective routing optimisation models for MPLS networks. The major contribution is the proposal of a multiobjective routing optimisation framework for MPLS networks. The major features of this modelling framework are: the formulation of a three-level hierarchical routing optimisation problem including network and service performance objectives, the inclusion of fairness objectives in the different levels of optimisation and a two-level stochastic representation of the traffic in the network (traffic flow and packet stream levels). A variant of the general model for two classes Work partially supported by programme POSI of the III EC programme cosponsored by FEDER and national funds. of traffic flows, QoS traffic and Best Effort traffic, is also presented. Finally a stochastic teletraffic modelling approach, underlying the optimisation model, is fully described.

A Hierarchical Multiobjective Routing Model for MPLS Networks with Two Service Classes

“…This theoretical foundation is based on a conjecture concerning the definition of marginal implied costs for QoS flows and BE flows, presented for the first time in this paper, which is an extension and adaptation of earlier definitions of implied cost for single service networks with alternative routing in [18]. The structure of the heuristic procedure for resolving the problem is analogous to the one described in detail in [7,26]. The new version of the heuristic, presented here, is based on a constrained bi-objective shortest path model, the objective functions of which are QoS or BE marginal path implied costs, depending on the class of the routed traffic, and path blocking probabilities.…”

“…As discussed in [7], a significant number of routing models for MPLS has been proposed in the literature in recent years which often differ in key instances of the modeling framework. Based on the analysis of the remarkable differences observed in the models proposed in this area, a discussion on key conceptual issues involved in the various modeling approaches and a proposal of a generic hierarchical multiobjective networkwide routing optimization framework or "meta-model" has been presented in [7].…”

“…Based on the analysis of the remarkable differences observed in the models proposed in this area, a discussion on key conceptual issues involved in the various modeling approaches and a proposal of a generic hierarchical multiobjective networkwide routing optimization framework or "meta-model" has been presented in [7].…”

“…The possibility of applying this modeling framework to a MPLS type network, already outlined in [7], namely by considering two classes of service, QoS traffic (first priority traffic) and Best Effort (BE) traffic (second priority traffic), was a major motivation for this work.…”

“…This work presents, in detail, a model for multiobjective routing in MPLS networks formulated within the framework developed by the authors in [7], assuming that there are two classes of services (and different types of traffic flows in each class), namely QoS and BE services. The flows of QoS type (first priority flows), when accepted by the network, have a guaranteed QoS level, related to the required bandwidth, while BE traffic flows, which are treated in the model as second priority flows, are carried by the network in order to obtain the best possible QoS level for the current network routing solution.…”