一种IPv6域间路由宣告中的前缀置换方法

Prefix Substitution Method on IPv6 Inter-domain Route Advertisement

提出一种增强IPv6网络BGP路由聚合能力的方法.该方法建议将Provider Independent(PI)地址空间的前缀映射为PA地址空间中相应大小的地址块,然后宣告BGP路由.该方法需要在AS边缘路由器(ASBR)建立前缀置换映射表.必要时采用前缀映射置换的方法处理进出AS的IPv6分组.该方法仅在AS边缘路由器部署,不影响域内路由;该方法提高了BGP聚合路由的可能性,提高了互联网的路由可扩展性.本文的理论分析得出的基本结论是,该方法的地址空间开销和分组转发开销与被置换的PI地址在可路由IP地址空间中的占比有关.采用该方法,对使用PI地址的站点需要重定向服务提供外部访问连接.

This paper proposes a method to enhance the route aggregation capacity of the IPv6 BGP advertisement. It suggests mapping Provider Independent prefixes into corresponding Provider Aggregateable （ PA ） prefixes before advertising BGP routes. It needs to establish a mapping table at AS border routers （ ASBRs ）. The ASBR has to substitute the prefixes of the ingressing and egressing packets when necessary. This method only requires deployment at ASBRs and it will not influence the intra-domain routing. The map- ping of PI prefixes with PA prefixes imcreases the probability of route aggregation in the BGP, consequently enhances the routing scalability of the Internet. Our theoretical analysis gives the following evaluation： the consumption of addresses and computational o- verheads of this method mainly depend on the ratio between the PI address space and the whole routeable IP space. When adopting the method in this paper, it may require redirection service when some hosts from other ASes need to access to the networks that use PI addresses.