Network address translation-protocol translation distribution mechanism using DNS system

Abstract

Internet Protocol version 6 (IPv6) was announced as the new version of the internetworking protocol designed to address the scalability and service shortcomings of the current standard. During the coexisting period of IPv4 and IPv6, IPv6 would not be compatible with IPv4. Programs and systems based on one protocol cannot communicate with those based on the other. Consequently, it is necessary to develop a smooth transition mechanism that enables applications to continue working while the network is being upgraded. There have been some translation mechanisms proposed by Internet Engineering Task Force (IETF). Among the translation mechanisms, the Network Address Translation-Protocol Translation (NAT-PT) is the most popular mechanism in general situations. However, due to its topology limitation problem, every packet must send/receive through the same NAT-PT router to maintain session information between IPv4 and IPv6. Therefore, NAT-PT must be located at the edge router between IPv4 domain and IPv6 domain. Another problem in that, when the load of translation requests increases, the edge router may become a performance bottleneck. Also when the users try to connect to heterogeneous network, all the edge routers must have NAT-PT function. These problems can be removed by using multiple NAT-PT routers between IPv4 domain and IPv6 domain. To maintain session information between IPv4 host and IPv6 host, we distribute the traffic to NAT-PT routers according to the classification of session level or destination host level. In this thesis, we propose an NAT-PT distribution mechanism using DNS system. The concept of proposed scheme is when users want to connect to the server, the requests are sent to DNS server for domain name resolving action and the DNS server responds to them with IP address via domain name resolving. By doing so, the user can connect to server with IP address responded from the DNS server. This mechanism can provide IPv4/IPv6 translation service t...