Traffic engineering of MPLS backbone networks in the presence of heterogeneous streams

Heterogeneous streams (due to issues such as disparate traffic characteristics of each stream, or competing customers’ traffic) raise the issue of whether to multiplex (some of) these streams. In an MPLS network, such multiplexing can be considered by putting different streams into a tunnel identified by a single label-switched path (LSP), assuming that the different LSPs are assigned a reserved share of the resources. This issue becomes even more important in the traffic engineering of a backbone network when a decision needs to be made on which streams to multiplex when there are constraints on tunneling and capacity along with routing requirements for tunnels. In this paper, we introduce a distortion factor due to heterogeneous streams in traffic engineering of MPLS backbone networks in the presence of tunneling and capacity constraints by formulating a distortion-aware non-linear discrete optimization problem. Furthermore, we present a two-phase heuristic approach to solve this formulation efficiently. In the first phase, the problem is decoupled into two subproblems and in the second phase we show how the non-linear problem (for one of the subproblems) can be simplified. We then present numerical results for both small and large networks to show where and how our approach helps to determine when and which streams to multiplex depending on whether the tunneling and/or capacity constraint is dominant; furthermore, by comparing our distortion-aware traffic engineering model with a distortion-ignorant traffic engineering model, we show the benefits of our approach.