Traffic Engineering Using Multiple Multipoint-to-Point LSPs

Traffic engineering aims to optimize the utilization of existing network resources for load balance and failure recovery, and these are to be accomplished in a scalable fashion. This paper proposes a traffic engineering scheme using multiple multipoint-to-point (m-t-p) Label Switched Paths (LSPs) which can reduce the number of LSPs and required labels in links. The scheme consists of m-t-p LSP creation and flow assignment. Routes are first selected, and m-t-p LSPs are designed to include them. The m-t-p LSP design problem is formulated as a 0−1 integer programming problem. The flow assignment problem is formulated as a mixed integer programming problem in which maximum link load, i.e., maximum congestion, is minimized. Numerical comparisons with the conventional pointto-point LSP approach show that the m-t-p LSP approach can reduce the number of required LSPs and labels. Moreover, numerical comparisons with conventional Shortest Path Fast based flow assignment show that our flow assignment scheme can reduce maximum link load. Keywords—Traffic engineering, MPLS, multipoint-to-point LSP, flow assignment