The Research And Application On Intranet IPv6Transition Technology

The Internet Corporation for Assigned Names and Numbers (ICANN) announced the last batch of IPv4addresses has been allocated in March2011,which indicates it is imminent that IPv6protocals to replace IPv4protocals. Currently, most of Intranet network infrastructures are based on the IPv4protocol, so it will take a long time to translate IPv4environment to IPv6environment. Meanwhile, IPv4and IPv6will be coexisting. We must study a suitable Intranet transition strategy to ensure the IPv4network and IPv6network seamless connection.This paper consists of three mainly parts.Firstly,studying several commonly used transition techniques,such as dual stack, tunneling and translation, and having a deep research on the principles and the communication process of the IVI translation mechanism.On this basis, proposed a IVI program in the form of Netfilter extension modules.Secondery, giving the specific implementation and analysis to the IVI matching module and target module. Finally,finishing the IVI gateway structures and the experimental verification in experiments.The main work of this paper includes the following aspects:1、To analyzes the advantages disadvantages and application scenarios of the most typical transition technologies including dual-stack, tunneling and translation.At the same time,this paper gives a depth study and comparison of them.2、Designed the overall implementation of IVI mechanism in the Linux kernel. IVI mechanism is completed by adding IVI extension modules in the Linux kernel firewall Netfilter,including IVI matching module, IVI target module and its associated header file. IVI extension modules adopt the latest plug-in module xtables-addons rather than the outdated patch-o-matic.The new method has the advantages of simple,time-saving and high rate of success.Especially,the external plug-in provides a good convenience for the future expansion and optimizing.3、Designed and implemented the IVI matching module including IVI user space and kernel space.The function of IVI user space is to receive matching information from users and place it in the kernel data structures while the IVI kernel space is really to execute the matching module. The IVI kernel space achieves its function by matching the incoming packets compared to rule base,which includes IP address information, address prefix,and so on.And the matching packets will be handled by the IVI target module.4、Designed and implemented the IVI target module.It is responsible for translating IPv4protocals and IPv6protocals,that is, address and protocol translation algorithm and the translation algorithm between ICMPv4and ICMPv6.After the research the protocals,this paper proposes a new check sum updatating algorithm for pseudo header in TCP and UDP translation process.It is conducting check sum by updating for the changes rather recalculating all the field in the packets,which can effectively improve the computation efficiency.5、There are some problems in IVI DNS.For examples,IVI6(i) can not access the dual-stack server and dual-stack node in IPv6environment can not give the correct question for the A type DNS query response message in IPv4environment.After the deep analysis of these problems, this paper put forward a improved DNS solution,which can effectively solve the defects in existing domain name resolution module, thereby improving the transition program in the IVI DNS module deployment mechanism.IVI translation mechanism can effectively solve the coexistence problem of IPv4and IPv6network in communicating with each other for IVI gateway is stateless translation and has a good performance.The IVI extension modules as a loadable module in the kernel can be easily integrated into existing kernel with great flexibility.The IVI gateway puts forward in this paper is suitable for large-scale Intranet, it can provide practical application of reference for widely deploy Intranet transition network.