> If Optimistic DAD doesn't allow for unicast responses to > router solicitations, the potential for fast advertisement > to such hosts is severely diminished.
So how could something work? I'm assuming that somehow, perhaps using a token bucket filter instead of a fix 1 every 3 seconds limit, we can accomplish faster RA responses to RSes, but the DAD interactions are still perplexing. Alternative 1: The RS contains the tentative address as the source, but no source link-layer address option (since that would override any link-layer address recorded in the routers in the case of an address conflict). Thus in order for the router to unicast the RA it needs to perform a NS/NA exchange with the host. This is only done when the router doesn't have a neighbor cache entry, and the resulting NA has override=0. So this will never replace a cached link-layer address in the case of a conflict. But the exchange is 4 packets instead of 2. Alternative 2: Why not conceptually define the override flag for the RS to accomplish a 2 packet exchange? A compatible way to do this is to define a new "tentative source link-layer address option" which would only be used by the receiver if it doesn't have a cached address i.e., would never override an existing address. (As an aside, this could also be used for NS packets.) Erik -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
