A New Pre-emption Policy For MPLS-TE Networks

The pre-emption mechanism may be used in Multi Protocol Label Switching Traffic Engineering (MPLS-TE) networks in order to reduce the number of rejected tunnels during failure. But pre-emption may have an impact on the convergence time, and it is required to minimize the number of pre-emptions per tunnel. For that purpose this paper proposes a new pre-emption policy allowing reducing or limiting the number of pre-emptions per tunnel, after a network failure. Two approaches are proposed: A pre-emption reduction approach where the least preempted tunnels are pre-empted in priority and a pre-emption limitation approach where a tunnel cannot be preempted more than N times during a given period. Simulation results show that we can limit the maximum number of pre-emptions for a given tunnel to only one, without significantly diminishing the rejection reduction capabilities.