Study And Realization On Topology Discovery Of IPv6 Network

More network applications and larger network scale reveal the limitations of Internet network based on IPv4 protocol, such as lack of address and none of Quality of Service. Since 1991, IETF has begun to research the next generation Internet protocol—IPv6 protocol that is used to substitute for IPv4. As there will be a great deal of network devices in IPv6 network and the redefinition of many kinds of protocols which are correlative with IPv6, IPv6 network management is different from IPv4. With the exploding scale and complexity of IPv6 network these years, it's more and more important to get a complete and correct Internet topology, which can be used in these fields such as network management, network optimization and fault location. Due to existed techniques for IPv4 network topology discovery can't be ported to IPv6 networks directly. It becomes more and more necessary to discover and manage IPv6 network topology automatically.At first, this thesis presents the advantage of IPv6 protocol and its effect to TCP/IP model. Secondly, it shows the method of network topology automatic discovery in IPv4 and difficulties of IPv6 topology discovery.As for the network layer topology discovery, the thesis extends the scope of Traceroute method; makes the best of characteristic of IPv6 and combines the concrete network environment to design a discovery method for route-level topology of IPv6 backbone network. Routing header is used to improve the overlay ratio of cross-link; flow label field of IPv6 header is used to realize multi-path probing by single node. Some key issues are solved in router-level topology discovery, including alias resolution, choice of initial target IP address set and so on.As for the data link layer topology discovery, due to the switch device in IPv4 will continue to employ in IPv6. The method based on FDB and STP protocol can server for discovering the connection of switches in IPv6. Furthermore, IPv6 neighbor discovery protocol and multicast technology can be used for collecting node (host and gateway router) information.Due to the coexistence of IPv4 and IPv6 for a long time, how to identify dual-stack node and tunnel has important significance to topology discovery and network management during transition. Some research on special network elements discovery has been done, which is based on node name resolution, PMTU probing method and so on.Finally, an IPv6 network topology automatic discovery prototype system based on above methods and techniques is designed and implemented in the thesis. The system has been tested in IPv6 network lab of Chongqing University and in Cernet2 backbone network. The correctness and practicability of the system is validated by their tests.