Label Switched Paths Re-configuration under Time-Varying Traffic Conditions

Multiprotocol label switching (MPLS) has several advantages over destination-based IP routing protocols: it allows to setup end to end paths explicitly (also called label switched paths, LSP), to better monitor the traffic on these LSPs, to perform admission control, etc. While routing along a LSP is considered faster than IP routing, the operation of changing a LSP pipe requires processing and bandwidth resources in the network. This paper investigates cost optimized ways for re-dimensioning existing LSP pipes, to accommodate changing traffic demands. In the presented model the goal is to maximize the amount of carried traffic, while keeping the number of LSP modifications at a minimimum. The presented off-line procedure can be made part of a periodical traffic engineering process. We present a mixed integer LP formulation of this problem, a more efficient heuristic, as well as results on test networks.