Research On Active Detection Technology For Large Scale Network Topology

Because of the increasingly larger scale and complex structures of the network topology,the network topology has brought great challenge to the efficient network management.Mastering the network topology is the premise for network administrators to manage the network effectively.Therefore,how to obtain network topology efficiently and accurately becomes one of the research hotspots in computer network.This paper aims at studying and analyzing the direction on active detection technology for large scale network topology.In this paper,the topology discovery algorithm was studied.The traditional Traceroute method will generate a large number of redundant probes when the network topology is detected,and can't obtain the network topology efficiently.In order to reduce the redundant detection,Doubletree algorithm reduces intra-monitor redundancy and inter-monitor redundancy in the network topology discovery process by setting the local stop set and the global stop set.Although the Doubletree algorithm reduces the redundant detection and improves the efficiency of detection,the Doubletree algorithm still has some shortcomings in communication traffic among probe sources,the efficiency of detection and integrity.Therefore,this paper presents a parallel topology discovery algorithm based on dynamic rotation.This algorithm reduces the communication traffic among probe sources of Doubletree algorithm by changing the shared global stop set,and improves the integrity of Doubletree algorithm and the efficiency of detection by adding the random verification algorithm and the parallel detection mechanism in the topology discovery process.Comparing with Doubletree algorithm,this algorithm is superior to Doubletree algorithm in communication traffic among probe sources,the efficiency of detection and integrity.In this paper,the alias resolution technology of router was studied.In general,a router usually has a number of different IP addresses.Therefore,In order to reflect the network topology accurately,these IP addresses belong to the same router must be merged by using the alias resolution technology.The alias resolution method based on filtering should filter the aliases first and then verify the aliases,which improves the efficiency of alias resolution as a whole.In this paper,a new distributed alias resolution method based on geography was proposed to improve and optimize the shortcomings from alias filtering and alias verification.This method based on the principle that the non-border routers in different areas can't havealias relationship.And an IP lookup algorithm based on IP address set is proposed to improve the efficiency of alias filtering.The firewall will filter the UDP packets when the IPID(UDP)was adopted to verify alias in the alias verification,which cause the aliases lacking of alias integrity.In order to solve this problem,a distributed alias verification model based on geography was proposed to improve the efficiency and integrity of alias verification.Through contrast experiments,this method improves the efficiency and integrity of the alias resolution.Finally,this paper designs and implements a high-performance network topology active detection system,which has been tested.The function and performance test results of this system show that this system can detect the network topology efficiently and has a high practical value.