Research On Automatic Discovery Algorithm Of Link Layer Topology

With the rapid development of the Internet,the scale of computer networks has become increasingly large,and the network structure is more and more complex,which makes people's demand for network management become more and more urgent.Network topology discovery technology is a basic function in network management and the cornerstone of network management system.An accurate network topology can provide network administrators with direct and effective network structure and associated information.In different levels of network topology discovery,most of the research focus on the topology of the network layer.Therefore,the network layer topology discovery algorithm has been very mature.Compared with the topology discovery at the network layer,the topology of the link layer is relatively few.But with the rapid development of the network in recent years,the automatic discovery of link layer network topology has become a hot spot in network management field,it has a wide range of application prospects.This paper mainly studies the network topology discovery technology of link layer.At present,the discovery algorithm of link layer topology is mainly based on spanning tree protocol and address forwarding table(AFT).Based on the analysis of the two existing algorithms,an improved link layer topology discovery algorithm is proposed.The idea of this algorithm is to use the spanning tree protocol algorithm to discover the switch that supports the protocol and build the topology of the main body firstly;And then based on the information in the AFT,delete some switches;Finally,according to the information of modified AFT,use the algorithm based on address forwarding table to insert the remaining switches into the topology of the framework.Experiments and analysis show that:compared with the topology discovery algorithm based on spanning tree protocol,the improved algorithm can find the network equipment which does not support spanning tree protocol in the network and improve the accuracy of the topology.Compared with the topology discovery algorithm based on address forwarding table,the address forwarding table information to be processed by the algorithm is relatively simple and reduces the time complexity.Based on the link layer network topology discovery algorithm described above,the paper discusses the function realization process of several management modules in the network management system.Firstly,the architecture design of the system is introduced,and the three-tier architecture of the system is described respectively.And the equipment management,performance management,alarm management and topology management module of the system are analyzed in detail.The network topology management mainly solves the topology connection diagram,link status and device performance alarm of all the devices in the whole network.The function modules of the system are based on the network topology,mainly to solve all the equipment within the network topology connection diagram,link status,equipment performance alarm.The network administrator can evaluate the fault equipment according to the topology information and timely process the alarm information,quickly eliminate the network fault and improve the network performance.