A distributed LSP scheme to reduce spare bandwidth demand in MPLS networks

A preplanned path-protection scheme with sufficient spare bandwidth is appropriate for real-time fault restoration in multiprotocol label switching (MPLS) networks. In this case, however, it is important to reduce the amount of spare bandwidth to prevent degradation of network efficiency. A distributed label switched path (D-LSP) scheme is proposed to reduce the amount of spare bandwidth required for protecting against network faults in MPLS networks. The main idea of the proposed D-LSP scheme is to partition traffic into multiple LSPs, each of which is established on a distinct link-disjoint route between each pair of end nodes. The D-LSP scheme is evaluated in terms of the reduction ratio of total network cost in comparison with the conventional LSP scheme. Traffic partitioning in the D-LSP scheme can decrease the statistical multiplexing gain (SMG) obtained by aggregating IP packet flows into an LSP. The tradeoff between spare bandwidth reduction and degradation of SMG due to traffic partitioning is also investigated. The numerical results show that the proposed D-LSP scheme yields the network cost-reduction ratio (NCRR) of at least 29%, 27%, and 15% for the networks where average node degrees are 4.6, 4.4, and 3.2, respectively. The D-LSP scheme shows the similar performance of NCRR in both Markovian traffic and self-similar traffic environments.