Encontrados 13 documentos, a visualizar página 1 de 2
Determinação de k caminhos disjuntos nos SRLG
Gomes, Teresa; Soares, Miguel; Craveirinha, José; Jorge, Luísa; Melo, PauloA determinação de um conjunto de caminhos disjuntos nos SRLG é um problema NP-Completo, de grande interesse no desenvolvimento de métodos de encaminhamento resiliente. Existem poucas heurísticas para a determinação de k de caminhos disjuntos nos SRLG, e tanto quanto nos foi possível averiguar, não existe nenhuma heurística que tente minimizar o custo total do conjunto de caminhos a determinar. São aqui proposta...
Performance analysis of algorithms for calculation of SRLG disjoint paths of mi...
Gomes, Teresa; Soares, Miguel; Craveirinha, José; Melo, Paulo; Jorge, Luísa; Mirones, Vítor; Brizído, AndréEnsuring the resilience of telecommunications networks is an ongoing concern of telecommunications operators. In a Generalized Multiprotocol Label Switching (GMPLS) [4], network information about sets of links that share risks of failure, called Shared Risk Link Groups (SRLG), can be distributed [3]. This information allows Path Computation Elements (PCE) [1] to determine protected routes, i.e. compute a pair (...
Proteção em redes GMPLS considerando informação acerca dos SRLG
Gomes, Teresa; Soares, Miguel; Craveirinha, José; Melo, Paulo; Jorge, Luísa; Mirones, Vítor; Brizído, AndréGarantir a resiliência das redes de telecomunicações é uma preocupação permanente dos operadores de telecomunicações. Numa rede Generalized Multiprotocol Label Switching (GMPLS) pode ser distribuída informação acerca de conjuntos de arcos que partilham riscos de falha, designados por Shared Risk Link Group (SRLG). Esta informação permite aos Path Computation Elements (PCE) determinar rotas protegidas, ou seja c...
On a Bicriterion Server Allocation Problem for a Multidimensional Erlang Loss S...
Esteves, Jorge Sá; Craveirinha, JoséIn this work an optimization problem on a classical elementary stochastic system system, modeled as an Erlang-B (M/M/x) loss system, is formulated by using a bicriteria approach. The problem is focused on the allocation of a given total of k servers to a number of groups of servers capable of carrying certain offered traffic processes assumed as Poissonian in nature. Two main objectives are present in this for...
An effective algorithm for obtaining the minimal cost pair of disjoint paths wi...
Gomes, Teresa; Craveirinha, José; Jorge, LuísaRouting optimisation in some types of networks requires the calculation of the minimal cost pair of disjoint paths such that the cost functions associated with the arcs in the two paths are different. An exact algorithm for solving this NP-complete problem is proposed, based on a condition which guarantees that the optimal path pair cost has been obtained. This optimality condition is based on the calculation o...
A meta-model for multiobjective routing in MPLS networks
Craveirinha, José; Girão-Silva, Rita; Clímaco, JoãoAbstract 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 con...
Efficient calculation of the most reliable pair of link disjoint paths in telec...
Gomes, Teresa; Craveirinha, JoséIn transmission networks an important routing problem is to find a pair of link disjoint paths which optimises some performance measure. In this paper the problem of obtaining the most reliable pair of link disjoint paths, assuming the reliability of the links are known, is considered. This is a non-linear optimisation problem. It is further introduced the constraint that the length of the paths should not exce...
Internet packet routing: Application of a K-quickest path algorithm
Clímaco, João C. N.; Pascoal, Marta M. B.; Craveirinha, José M. F.; Captivo, M. Eugénia V.This paper describes a study on the application of an algorithm to rank the K-quickest paths to the routing of data packets in Internet networks. For this purpose an experimental framework was developed by considering two types of random generated networks. To simulate values of the IP packet sizes, a truncated Pareto distribution was defined, having in mind to reflect a key feature of Internet traffic, namely ...
An automated reference point-like approach for multicriteria shortest path prob...
Clímaco, João; Craveirinha, José; Pascoal, MartaAbstract In this paper we introduce a method of analysis for the automated ordering and selection of solutions of a multicriteria shortest path model. The method is based on a reference point approach, where the paths in a specific priority region are ranked by non-decreasing order of a Chebyshev metric. In order to list paths according with this objective function a labelling algorithm is proposed. The develo...
On a bi-dimensional dynamic alternative routing method
Martins, Lúcia; Craveirinha, José; Clímaco, João N.; Gomes, TeresaThe analysis of a bi-dimensional dynamic routing model for alternative routing telecommunication networks led to the identification of an instability problem in the synchronous path selection associated with the complex interdependencies among the coefficients of the objective functions and the computed paths for every node pair. In this paper an analytical model enabling to make explicit this problem and evalu...
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