At Thu, 19 Feb 2009 21:56:21 +0100, Alexandru Petrescu <alexandru.petre...@gmail.com> wrote:
> > If what you mean is something like this: > > - router A advertises P::/48 with L=1, A=1 > > - router B (a downstream of A) advertises P::/52 with L=1, A=1 > > - router C (a downstream of B) advertises P::/56 with L=1, A=1 > > while allowing hosts to configure addresses with the shorter prefixes, > > then hosts won't be able to communicate off-link: host X, which > > receives an RA from router C and configures P::x, would tries neighbor > > discovery to send packet to a different host Y, which receives an RA > > from router A and configure P::y, because P::y is covered by X's > > on-link prefix, P::/56. This attempt will of course fail. > > > Thanks for digesting an example. I suppose the illustration is: > > 48 52 56 > --A----B----C--- > | | > Y X > You seem to say that if RA /56 A=L=1 for X, and /48 for Y, and if X > wants to send a packet to Y (having never sent it a packet before) - it > will fail. However, if X and Y were autoconfigured with /64 prefixes > then it would work; if Iunderstand you correctly. Let's be even more specific. Assume the /48 prefix is 2001:db8:1111::/48. What I thought in the previous message was: - A (or B) advertises 2001:db8:1111::/48 and Y configures 2001:db8:1111::1 (by the hypothetical extension for address configuration). - C advertises 2001:db8:1111::/56 and X configures 2001:db8:1111::2 (by the hypothetical extension for address configuration). but by being specific I realized I should have used a different example. So let me revise the situation: Assume the /48 prefix is 2001:db8:1111::/48. - A (or B) advertises 2001:db8:1111::/48 and Y configures 2001:db8:1111::1 (by the hypothetical extension for address configuration). - C advertises 2001:db8:1111:cc00::/56 and X configures 2001:db8:1111:cc00::2 (by the hypothetical extension for address configuration). The revised question is, how can host Y send a packet destined to 2001:db8:1111:cc00::2 via router B, instead of directly trying neighbor discovery (which will fail)? Since Y is told 2001:db8:1111::/48 (which covers 2001:db8:1111:cc00::2) as an on-link prefix, the destination address should be a neighbor of Y. --- JINMEI, Tatuya Internet Systems Consortium, Inc. -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
