> I think it's easy to see the disagreement just comparing the responses > from Ole and James. > > Ole says: >> I don't see the point of doing address resolution on links without >> addresses. > > James says: >> IPV6CP (RFC 2472) negotiates >> only interface identifiers, and not addresses, and ND >> (2461) says that Neighbor Discovery is supposed to be implemented for >> point-to-point links, so I'd expect ND to be used on those links.
I didn't interpret James's reply to mean that his interpretation was to do address resolution on a link. James can you clarify. > To answer "what's the possible interoperability issue", Markus Jork > nailed it in the referenced thread: >> If one implementation sends a NS and >> expects to see a NA before sending the first message to the neighbors >> address but the other implementation doesn't use NS/NA messages on the >> PPP link, there is a problem. the other peer should consider that as a NUD exchange. NS/NA messages must be supported on PPP links too, otherwise how can you do NUD. > We have now observed the problem Markus predicted, with real > implementations. That is, I know of two non-interoperable > implementations of RFC 2472. > > I think James' argument does have real substance. The quote from 2461 > section 3.2 is (especially the last sentence): > >> point-to-point - Neighbor Discovery handles such links just like >> multicast links. (Multicast can be trivially >> provided on point to point links, and interfaces >> can be assigned link-local addresses.) Neighbor >> Discovery should be implemented as described in >> this document. > > If this is the behavior we agree on, then I think that answers my > question. agree on PPP links should be treated as multicast links. that doesn't mean you should require address resolution before sending packets. 2461, 7.2.2. Sending Neighbor Solicitations When a node has a unicast packet to send to a neighbor, but does not know the neighbor's link-layer address, it performs address resolution. for PPP links we always know the link-layer address. cheers, Ole -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
