Interoperability Between IPv4 and IPv6 Clients and Servers
Most applications today support IPv4 and thus there is a need to run these applications on IPv6 access network. IPv4 can't meet the rising needs of the present internet. Moreover, IPv6 can solve the problems that IPv4 faced, and present more new features. The Internet must make the transition from IPv4 to IPv6. So the application which is based on IPv4 will be applied in the environment of IPv6. At present, windows system is widely applied. Many applications use Socket Application Program Interface.