Research On Multihoming Of IPv6 Networks

Multihoming is an important service manner of networks. It can enhance the reliability of networks, carry out load-balancing, reduce transmission delay, increase networks bandwidth, keep transport-layer survivability and offer many other benefits. With the development of the next generation Internet, IPv6 Multihoming technology will be widely applied in the future.Currently there are many IPv6 Multihoming methods which have their own characteristics respectively. However, all of them have defects and need to be further perfect. Keeping transport-layer survivability is one of the main goals of Multihoming. Under the conditions of switching the paths, the Multihoming sites still use the original source addresses to keep the session not to be broke off. However, the above behavior results in the fact that packets will be discarded by the routers of upstream ISP because of the Ingress filtering, which makes the upper application session interrupted. In order to simultaneously realize session survivability and satisfy ingress filtering, this thesis proposes a new IPv6 Multihoming method.The main work of this thesis can be summarized by the following aspects:1. We introduce the present status of IPv6 Multihoming and expatiate all of IPv6 Multihoming methods. Then we classify them into four strategis: Routing strategy, Host-Center strategy, Gateway strategy and Changing the Transport Layer or Network Layer protocol stack strategy. After elaboration in details as well as comparing them, we point out the required conditions in pratical application.2. We make a detailed discussion about a new kind of IPv6 Mutihomingmethod——Address Sheltering and Identifying (ASI) mechanism. We explain the mainprinciples of the mechanism and then analyze the implementation process of Sheltering and Identifying at Site Exit Router and peer host.3. The key techniques in ASI mechanism are elaborated detailedly. This include: How the messages exchang between two Site Exit Routers and between the Site Exit Router and its peer host, how we deal with the Packets Too Large and MTU problems in the Sheltering Process and what are the ASI mechanism's solutions on the networks safe issues.4. We design the implementation project of ASI mechanism. After aborative analysis of sending and receiving datagrams in Linux TCP/IP protocol stack, we set up the Sheltering module and Identifying module in the background of IPv6 networks. Then we illustrate each stage of working process and explain the corresponding functions in the course process of sheltering and identifying packets.5. We have verified the prototype system of ASI mechanism. Through the analysis of experiment data, we compare the value of RTT and TCP connecting speed between the normal transmitting path and the switching transmitting path, and these indicate the feasibility of ASI mechanism.The IPv6 Multihoming technology is developing continuously and rapidly. In this dissertation, we propose a new IPv6 Multihoming methods and the study may have some instructional significance and constructive contribution to the future networks of Multihoming.