Excerpts from Tony Li on Sun, Apr 19, 2009 09:44:28AM -0700: >> Unicast is a special case of anycast in which there is only one >> destination endpoint. > > Nothing absurd about it. It's been said many times that unicast is a > special case of multicast and your observation is that anycast fits in > the middle of that hierarchy, since anycast is also a special case of > multicast where delivery is to only one receiver.
Tony: I think these are statements about routing, not about addressing, but I'm not sure. How would what you say here work with the definition of a locator? Excerpts from William Herrin on Sun, Apr 19, 2009 07:32:53PM -0400: > > Nothing absurd about it. It's been said many times that unicast is a > > special case of multicast and your observation is that anycast fits in the > > middle of that hierarchy, since anycast is also a special case of multicast > > where delivery is to only one receiver. > > Hi Tony, > > I disagree with you there. Broadcast and Multicast are forms of > non-determinisitic routing. Anycast and unicast are both forms of > deterministic routing. Is that because the _potential_ recipients are already known? > There's a wide gulf between deterministic and non-deterministic > routing. What works efficiently for one just flat doesn't work well > for the other. > > I claim that on the deterministic side, the difference between anycast > and its unicast subset is sufficiently trivial that a well conceived > protocol will neither need nor want to treat the two cases > differently. > > When I say, "Unicast is a case of anycast in which there is only one > destination endpoint," I really mean it. Unicast doesn't exist. It's > just a convenience label for Anycast in which only one destination > endpoint is currently active, and that's precisely how the routing > system treats it. > > The same can't be said of multicast. Multicast has different semantics > even if there's only one host in the group. > > Still think I haven't proposed a radically different way to visualize > the routing system? How would you change the definition of a locator to match this? _______________________________________________ rrg mailing list [email protected] http://www.irtf.org/mailman/listinfo/rrg
