| BGP is the de facto inter-domain routing protocol of the Internet. Simulation is one of the most efficient methods for study BGP protocol. With the development of the scale of simulative network, route simulation becomes a key problem. Most of current BGP simulation has pretty low efficiency. In order to improve the efficiency of BGP simulation, this paper presents some optimization methods for reduce the CPU load. Route protocols of the Internet are firstly summarized. Border Gateway Protocol is especially explained. Technology of network simulation is narrated. At the same time, this paper introduce the software of network simulator, emphasis is BGP++, which is a simulator of BGP.In the following, some optimized methods for route simulation are presented. One is improvement for the searching process of route. Modification is made for the NIx-Vector. The neighborhood gathering of current node is looked up for destination before compute NIx-Vector. If the destination node were found, this node ID would take as the address of next hop, the process of NIx-Vector computation would not be executed. The other is betterment for process of simulation. Firstly, the characteristic of TCP is getted rid of during the BGP simulation. Relationship between BGP and TCP is removed in the simulator. Secondly, the KeepAlive-Notification mechanism of BGP is modified to decide whether a link state changes or not.At last, an experiment is designed and carried out under the Linux Operating System. The experimental results show that the efficiency of BGP simulation can be greatly improved with these optimization methods, the number of events generated during the simulation reduced largely, and the simulation time reduced greatly compared with the original BGP simulation in BGP++. |
