With the rapid development of the wireless network technology and communications equipment,it is hoped that the mobile node is not only the same as desktop access network, share resources and services,but also when the mobile node move between different networks, the mobile node can access from the Internet on the information they need to maintain communications,anytime,anywhere.In view of this situation,IETF(Internet Engineering Task Force)drawn up the mobile IP protocol in 1996 to develop an agreement to support the mobile Internet. When the mobile node moving from one subnet to another subnet,the switch happens in order to ensure the normal communications. switching could lead to the mobile node within a certain period of time can not send and receive data packet. How to switch the course to maintain uninterrupted communications to achieve a variety of real-time applications and shorten the disruption caused by switching to reduce the impact of switching on the quality of service is the focus of mobile IPv6 research.IETF proposed a lot of technical standards of Mobile IP switch,many researchers put forward a number of improvements in the basis of these standards,its purpose is to improve the quality of service switch process.
