A Constrained Multi-path Finding Mechanism Considering Available Bandwidth and Delay of MPLS LSP

Abstract

The Multi-Protocol Label Switching(MPLS) technology has been believed to be good for Traffic Engineering(TE) in Internet, which enables effective use of network resources, and maximizes network performance. The Constraint-based Shortest Path First(CSPF), which is the extension of SPF that is used in IP routing protocol, currently finds only one path satisfying the required bandwidth using link’s speed as a cost. That method is not proper for the voice traffic and other real-time applications, which require strict guarantee of packet delay. To solve this problem, we propose new path computation method, which considers current delay and available bandwidth simultaneously. If there may exist many paths satisfying the given constraints, the proposed method can find them in the order of low cost of each path. In case of multi-path, this method can also distribute traffic load among multiple paths to avoid network congestion. To evaluate the performance of the new proposed method, we compare the result of average available bandwidth rate and average delay of Label Switched Path(LSP)s with that of existing CSPF using our own developed path calculation simulator. Since MPLS TE supports explicit path establishment, by using this new proposed method, Internet Service Provider(ISP)s can optimize network performance and minimize packet delay for severe delay required traffic such as Video on Demand(VoD), Voice over IP(VoIP), etc.

This work is supported by KT Operations Support System Laboratory under grants the project 2002 arts and science services.