On 2012/02/07, at 14:03, Rémi Després wrote: > > Le 2012-02-07 à 13:07, Satoru Matsushima a écrit : > >> Hi Remi-san, >> >> On 2012/02/07, at 11:13, Rémi Després wrote: >> >>> Hello Ole, Tetsuya-san, Wojciech, >>> >>> In a use case described in the 4rd-U draft (sec 5.3), an ISP replaces its >>> dual-stack routing by IPv6-only routing. >>> For this, independently from the number of IPv4 prefixes it has to support, >>> it uses only one mapping rule. >>> (By replacing each IPv4 route by an equivalent IPv6 route, it ensures that >>> all customers keep their IPv4 addresses.) >>> >> >> I don't think that it could work as you explained in that section. For >> example, the BR would need to check a received packet from a CE whether it >> has correct source address in mapping rule or not. It means that the BR must >> know all address mappings for CE between IPv4 addresses and IPv6 prefixes. >> Is it correct understanding? > > Ingress filtering of the domain has checked that the IPv6 source starts with > the delegated IPv6 prefix, a /112 which includes the IPv4 address. In the > 4rd-E case, the BR checks that the source address in the IPv4 header matches > that of the IPv6 address. There is therefore no need for the BR to know all > IPv4 prefixes. At its IPv4 interface, all received packets start with one of > them. At its IPv6 interface, all packets it receives have an embedded address > that starts with one of these prefixes. >
It looks like that you treat default mapping rule as a basic mapping rule to check source address consistency on the BR. It should work, and the MAP too. >> I think that operators who already deploy such dual-stack network is >> supposed that they have address mapping table, > > I would rather suppose that ISPs that have added IPv6-prefix delegation, say > /56s, to an existing IPv4 network did it without mixing their IPv6 plan with > their IPv4 prefixes. > I am ready, however, to look seriously at individual cases where choices were > different. Basically provision MAP CE is based on its delegated IPv6 prefix in concept. It is opposed to your case but technically possible. Now I concern that it requires much complicated CE implementation. cheers, --satoru > > Regards, > RD > > > >> they can provision each CE individually, and also they are capable to >> distribute the default mapping rule since they should install it into the >> CEs. In that situation, what's the motivation of why the operator want to >> provision with only default mapping rule? >> >> cheers, >> --satoru >> >>> For this to work, the 4rd-U draft has a bit that, in the hub&spoke case, >>> differs between CE-to-BR and BR-to-CE directions. Thus, packets sent to a >>> CE take different routes depending on whether sent by a CE or a BR. >>> >>> I don't see how the equivalent could work with the MAP documents you edited. >>> Is it that such a use case is out of scope for MAP? >>> Or did I miss something? >>> >>> Cheers, >>> RD >>> >>> _______________________________________________ >>> Softwires mailing list >>> [email protected] >>> https://www.ietf.org/mailman/listinfo/softwires >> > _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
