A new topology aggregation scheme for scalable MPLS networks

Abstract

MPLS forwards the labeled packets on the Label Switching Paths (LSPs) which are built between ingress/egress Label Edge Router (LER) peers. As MPLS is the mirror of the IP layer, supporting the reachable capability to n destinations means that the MPLS network needs to build O(n) LSPs (n is determined by the granularities of the labeled packets). As the result, if it needs to set up a full mesh connection between each ingress/egress LER peer, O(n 2 ) LSPs are required. When the size of the MPLS network increases, the cost for maintaining the LSPs will severely increase. It is a serious problem for the scalability of MPLS networks. In order to achieve the scalability of MPLS networks, a network aggregation scheme based on weighted LER dominating set is proposed. The distributed construction method of the LER dominating set is introduced. The aggregation scheme can reduce the amount of the egress nodes when establishing LSPs so as to form an aggregated virtual backbone topology. At the same time, considering the bandwidth between the dominator and its dominatees, a bandwidth-constraint weight is used when constructing the dominating set. As the result, the dominating set has the optimal bandwidth feature and this scheme can apply to the network aggregation with other single constraint.