Research And Design Implementation Of NAT64

The problem of IP exhaustion can be solved by IPv6technology. However, due to thelarge amount of IPv4customers, the transition from IPv4to IPv6will be a long-termprocess. To implement the smooth transition of customers and services, long-termcoexistence of IPv4and IPv6will be an inevitable trend. At present, as most services of theInternet are based on IPv4, the IPv6customers also have the need to access the IPv4network. NAT64is a kind of stateful network address and protocol translation, whichallows IPv6-only clients to contact IPv4servers using UDP, TCP or ICMP.First, the thesis gives the research on some general IPv4/IPv6transition technologies,including dual-stack, tunnel and translation technology, elaborating their mechanisms,application scenarios as well as their problems and drawbacks, and then a method toimplement NAT64is proposed. After the fully analysis of the operating mechanism andpacket processing of NAT64, a system overall structure design is proposed. Thisimplementation including detailed designs of interface table, users table, prefix table, pooltable, vpn table, session table and filter table, which strives to combine the existinghardware platform and software platform, thus ensuring the complete realization of itsrelevant functions, while reducing the usage rate of system resources as more as possible.Finally, setting up an experimental network with an IPv6client, a NAT64router and anIPv4-only server connected sequentially in turn, function and performance are verifiedrespectively. Results shows that the functional requirements of NAT64are all realized, andthe operating performance meets expectations, while having bad effects on neither deviceperformance nor network environment.