RPX – a system for extending the IPv4address range

摘要

In recent times, the imminent lack of public IPv4 addresses has attracted the attention ofboth the research community and industry. The cellular industry has decided to combatthis problem by using IPv6 for all new terminals. However, the success of 3G networkdeployment will depend on the services offered to end users. Currently, almost allservices reside in the IPv4 address space, making them inaccessible to users in IPv6networks. Thus, an intermediate translation mechanism is required.Previous studies on network address translation methods have shown that Realm BaseKluge Address Heuristic-IP, REBEKAH-IP supports all types of services that can beoffered to IPv6 hosts from the public IPv4 based Internet, and provides excellentscalability. However, the method suffers from an ambiguity problem which may lead tocall blocking.This thesis presents an improvement to REBEKAH-IP scheme in which the side effectis removed, creating a robust and fully scalable system. The improvement can bedivided into two major tasks including a full investigation on the scalability ofaddressing and improvements to the REBEKAH-IP scheme that allow it to supportimportant features such as ICMP and IP mobility.To address the first task a method called REBEKAH-IP with Port Extension (RPX) isintroduced. RPX is extended from the original REBEKAH-IP scheme to incorporatecentralised management of both IP address and port numbers. This method overcomesthe ambiguity problem, and improves scalability. We propose a priority queue algorithmto further increase scalability. Finally, we present extensive simulation results on thepractical scalability of RPX with different traffic compositions, to provide a guideline ofthe expected scalability in large-scale networks.The second task concerns enabling IP based communication. Firstly, we propose anICMP translation mechanism which allows the RPX server to support important end-toendcontrol functions. Secondly, we extend the RPX scheme with a mobility supportscheme based on Mobile IP. In addition, we have augmented Mobile IP with a newtunneling mechanism called IP-in-FQDN tunneling. The mechanism allows for uniquemapping despite the sharing of IP addresses while maintaining the scalability of RPX.We examine the viability of our design through our experimental implementation.