Mpls Te Path Selection Algorithm

The paper briefly introduce tendency of the IP network development first, next described the concept, the characteristic and the basic application of MPLS technology, as well as basic definition, function, and commonly realization method of traffic engineering. Then elaborate four functions sub-module of the MPLS TE module: The package transmits unit, the information issued unit, the path selection unit, the signaling functions unit. The paper put emphases on research of MPLS TE (Multi-Protocol label Switching Traffic engineering). The key point is path selection algorithm of the path selection unit.Now, CSPF algorithm is mostly utilized in realization of MPLS TE ,however the LSPs with high priority only follow the shortest path to establish LSP, and always does not have the consideration to the preemption as a LSR establish a LSP to a destination node , therefore possibly this policy could needlessly cause the interruption of other traffic Which is preempted by the new establishing LSP. This paper propose a new algorithm and put emphases on illustrating the MPPF algorithm how to minimize the affection to established LSP as far as possible .The MPPF algorithm optimize a path by reducing the quantity of LSP which is preempted as far as possible.The paper detailedly elaborates the constrained conditions when LSRs select path in the situation of having no preemption in network, it also propose another COPF algorithm that consider a series of constrained conditions such as band width, delay and delay jitter, balanced load of flow, resources consumption and so on. The algorithm computer and select a most superior path under the conditions, namely a path which have link load lighter, have shortest jump properly, and satisfies the band width request in the candidate path.This paper promotes two algorithms to the situation of multicast. In the situation of Multicast, the MPPF algorithm consider some aspects to chooses a most reasonable path .It include the branch link quantity of preempted LSP which its downriver Multicast tree has, and that is whether the new LSP is belongs to the same Multicast tree.In the end, a method is proposed to build a shared multicast distribution tree using CR-LDP for expressing an application of COPF or MPPF. This paper puts emphasis on the discussion how to realize multicast with CR-LDP and use COPF or MPPF in MPLS network.