| IPv6 is the core protocol in the next generation internet, and its infrastructure is being deployed around the world. So IPv6 network topology discovery has very important practical significance. The goal of this thesis is to perform initiative topology discovery in IPv6 network on the router lever at the premise of non-cooperation. The complete process in topology discovery, from targets collection to topology visualizing, was studied in this thesis. Some methods were proposed to enhance the performance and coverage of topology discovery. An IPv6 Router-lever Topology Discovery Tool was developed, and was tested in CERNET2.First, the technology of targets collection was studied. It was pointed out that these methods used in IPv4 topology discovery can not be used in present IPv6 network directly, for a lack of network resources in it. A method of targets collection through prefixes expansion bases on search engine was proposed. 1128 IPv6 address and 453 prefixes of CERNET2 were collected in the experiment.Then, the source routing mechanism was studied in this thesis. It was pointed out that the topology discovery technology based on this mechanism has the advantage of flexible deployment in non-cooperation conditions but low efficiency for probing space expansion. Through the analysis of network phenomenon, a method of probing space suppression based on suppression rules was proposed to suppress the expansion of probing space.Third, through the examination on the weak points of stop-set method under source routing mechanism, a method of probing redundancy reduction based on path comparison was proposed to reduce the redundant probing and enhance the efficiency of topology discovery.Finally, the design and implementation of IPv6 Router-Lever Topology Discovery Tool were accomplished. Experimental results about CERNET2 showed that there were 896 nodes and 5398 links got by the tool with 79.21% reduction in the probing space and a decrease of 93.60% probing redundancy. |
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