Link Congestion Control Mechanism Based on Multi-Topology

There are two causes of network congestion: one is the lack of network resources, and the other is the irrational allocation of network resources. While traditional congestion control methods such as rate control, window mechanism, queue control, etc. can be applied to solve the congestion problem, but for the later congestion case, the fundamental solution is to make more effectively use of the network resources by adjusting the traffic routing choice when congestion occurs. Therefore, in the OSPF (Open Shortest Path First ) network, when congestion occurs in a certain link, lots of unused bandwidth may exist in the links which are not on the SPT. By adjusting the routes, traffic can bypass the current congest link and be forwarded to the destination consecutively, and the network congestion can be lightened eventually. In this paper we proposed a new link congestion control mechanism based on Multi-Topology: when congestion occurs in a certain link, according to the sub topology, the router can switch to the backup link computed in advance, so that traffic can avoid the current congestion to be forward to the destination. The simulation result shows that, our mechanism can make use of the remaining link bandwidth effectively to lighten network congestion.