Rerouting tunnels for MPLS network resource optimization

In Multi-Protocol Label Switching (MPLS) networks, traffic demands can be routed along tunnels called Label Switched Paths (LSPs). A tunnel is characterized by a path in the network and a reserved bandwidth. These tunnels can be created and deleted dynamically, depending on traffic demand arrivals or departures. After several operations of this type, the network resource utilization can be unsatisfactory, with congestion or too long routing paths for instance. One way to improve it is to reroute tunnels; the rerouting process depends on the LSP Quality of Service (QoS) requirements.Three levels of QoS are considered, with three associated types of LSPs. A global rerouting framework is proposed, which enables us to consider independently each type of LSP. Then, mathematical models are introduced and analyzed. A focus is made on complexity analysis and optimal resolution of these problems. Finally, some numerical results illustrate the theoretical analysis.