Distributed label switched paths based MPLS network

Abstract

This dissertation is concerned with network reliability and minimization of network redundancy in Internet using MPLS technology for its backbone networks. Multiprotocol label switching (MPLS) is expected to support QoS guarantees and traffic engineering in Internet backbone networks. Spare bandwidth reduction is important in MPLS networks where a preplanned network fault protection is required for fast restoration. In this dissertation, a distributed label switched path (D-LSP) scheme utilizing multiple parallel disjoint routes between a node pair is proposed to reduce spare bandwidth and total network cost. First, the D-LSP scheme is proposed. LSP partitioning which is a main mechanism of D-LSP scheme, is defined and analyzed in a specific MPLS network. In the proposed D-LSP scheme, demand traffic is partitioned and distributed over a set of sub-LSPs each of which is established on the disjoint routes. A demand traffic partitioning and distribution algorithm is derived from a specific MPLS network model. The partitioning of demand traffic in the D-LSP scheme yields a degradation in statistical multiplexing gain and thus, a trade-off between spare bandwidth reduction and increase in effective bandwidth required by each sub-LSP is investigated. The capability to reduce the network cost of the proposed D-LSP scheme is numerically analyzed and compared with the conventional LSP (C-LSP) scheme in which demand traffic is carried by a single LSP established between a end node pair. Second, the cost minimization problem in establishment of a D-LSP is formulated mathematically and the optimum solution is found in terms of the number of sub-LSPs and bandwidth distribution vector through a series of mathematical manipulation. The degradateion of statistical multiplexing gain is involved as a constraint of the cost minimization problem. Mathematical analysis of the proposed D-LSP scheme results in an algorithm finding the optimum number of sub-LSPs and bandwidth distr...