The Study And Implementation Of IPv4-IPv6 Multicast Transition Gateway

As the main protocol of the next generation Internet, IPv6 has got more and more attention. The CERNET2 project has made the development of IPv6 to a brand new phase. But IPv4 and IPv6 will co-exist for many years, possibly decades, so finding ways for the two to interoperate is important. There are a number of transition techniques that might be of help. But most of these have focused on unicast.As one of the main features of IPv6, multicast also needs to be considered. The transition technique that works well in unicast may not be fit for multicast, because multicast is one-to-many while unicast is one-to-one. Although a large number of reports and papers are written on transition. But very little has been written on multicast.This paper first studies some typical solutions for the multicast transition, and analyses their mechanism, strongpoint and shortcoming, and applicability. And then, a multicast transition model named MTG based on the protocol translation technique is given. MTG is a gateway placed between IPv4 and IPv6 network. It can be used for multicast video conference and multicast distribution. According to whether the multicast address mapping will change, the paper divides it into two parts: static mapping for address mapping with same size, and dynamic mapping for the others.After analyzing the implement of multicast in Linux kernel, this paper uses loadable module and netfilter framework to make MTG working on the network layer. And this enables MTG's high performance and expansibility for application layer protocol.This paper studies multicast membership activity for ASM. And it puts forward the method by collecting RP's MIB through SNMP or using programmable multicast router as RP to get multicast membership activity. And another method named SRP may be useful by placing the function on hosts than router.This paper also discusses network deployments and some SSM issues.The testing results show this model can enable the interoperation between IPv4 and IPv6 multicast, and is manageable and scalable.