> | >Every router (whether IPv4 or IPv6) knows what subnets its own interfaces > | >belong to (or, more accurately, what subnet numbers are assigned to > | >the links to which it has interfaces). That is the most basic > | >configuration info provided to a router -- it is provided with that info > | >in order to do unicast routing and forwarding. To enforce subnet-local > | >scope it is necessary simply to inhibit the forwarding of subnet-local- > | >destined packets between interfaces that do not belong to the same subnet. > > > If I have > > A --------- B --------- C > > and A-B is prefix1::/64 and B-C is prefix2::/64 and prefix1 != prefix2 > then subnet local multicast packets are not forwarded through B, right?
Yes. > > If I have > > A --------- B --------- C > > and A-B is prefix3::/64 and B-C is prefix3::/64 (a multi-link subnet) > then subnet local multicast packets are forwarded through B, right? Yes. > > And if I have > > A --------- B --------- C > > And A-B is prefix1::/64 and prefix3::/64, and B-C is prefix2::/64 and > prefix3::/64 (prefix1 != prefix2, prefix1 != prefix3, prefix2 != prefix3) > then subnet local multicast packets arriving at B are ..... ??? What is the source address of the subnet-local multicast address? Section 9, bullet 2 in the scoped addressing architecture doc describes the forwarding logic for this case. If the packet was sourced out of prefix3, it would be forwarded. If it was sourced out of one of the other prefixes, it would be dropped. Brian -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
