The Design And Implementation Of Dual Stack Lite Tunnel

With the rapid spread of Internet, the IPv4addresses have run out. The lack of cyberspace is prompting the forming and development of the IPv6. In1994, IPv6has been specified as the next-generation standard and the basis for future expansion of the Internet, which will replace the IPv4. However, due to various reasons, IPv4will still be supported before2025so that there is enough time to fix the new network protocol.In recent years, the application of IPv6is being used more and more widely, while the existing IPv4service could not immediately be abandoned. Therefore, viable transition solutions of IPv4/IPv6are needed, Dual-Stack Lite Tunnel is one of them which is used for IPv6edge network and realizing communication between IPv4network across the IPv6network.DS-Lite technology proposed an lightweight and scalable transition mechanism used in IPv6edge network through the tunnel. It inherit the basic idea of the4over6tunnel of edge network.When a customer’s device sends an IPv4packet to an external destination, DS-Lite encapsulates the IPv4packet in an IPv6packet for transport into the IPv6network and maps to a session. These IPv4-in IPv6tunnels are called softwires. The softwires terminate on a softwire concentrator or Address Family Transition Router, which decapsulates the IPv4packets and sends them through a Carrier-Grade Network Address Translation device. On the other hand, when the user(terminal) in the use of common IPv4address by port-based space division, each user has only one address portion of the "ownership"(divided through port). In this way, the IPv4address sharing are realized.First of all, the research background and significance of Dual-Stack Lite system are analyzed. Then it shows the main research content and system characteristics, and the related technology used in the system:tunnel, NAT, etc. As well as an analysis about the design of the hierarchical module for extendibility and maintainability. Finally, we test the DS-Lite system and introduced the test methods, process and the results.