The Research On MPLS Traffic Engineering And Constraint-based Routing Algorithm

With the fast development of the Internet in the 21^st century, new content is added everyday, flows in the network are also growing, and different types of business flows are various. These flows require a wide range of quality of service (QoS) guarantees on the basis of traditional IP network. For example, high transmission efficiency, dynamic-routing adjustment, flexible network control capability, etc. But the traditional IP network, using the shortest path algorithm to choose path, is the Best-effort delivery mode. This method overlooks the available network link capacity and the business's request. It will cause the entire network work without the utilization of the best. The traffic engineering based on Multi-Protocol Label Switching (MPLS) is adapted to these requests. It can precisely control the business flow in the network, rationally use network resources, access more business, and improve network efficiency. In this paper, we study and analyze MPLS-based traffic engineering (MPLS-TE) with a focus on its key technology: constraint-based routing algorithm. The constraint-based routing algorithm analyzes the collected network information and calculates routing under certain constraints. Giving comprehensive consideration to the various factors on the network, we try to find a light load path to improve network efficiency.This paper first introduces the basic principle of MPLS and imports the basic concept and work model of TE. On this basis, we analyze how to apply MPLS to TE and summarize the advantage of MPLS-TE.Secondly, the existing constraint-based routing algorithm are classified and analyzed. We put minimum bandwidth multi-path constraint-based routing algorithm to break the limitations of single-path algorithm's low success rate. The algorithm finds the most suitable path of the available bandwidth to meet part of a large bandwidth constraint and keep this process until all bandwidth is allocated to more paths, to reach the purpose that increases the success rate of finding bandwidth constraint path with fewest paths.Finally, we compare the simulation results with traditional routing algorithm, verify that multi-path constraint-based routing algorithm with minimum bandwidth has higher success rate than traditional single-path constraint-based routing algorithm does in meeting large bandwidth request, and therefore prove they have great effect on balancing network load.