Further reply Part 1 On Thursday 24 June 2010 at 16:17:10 Robin Whittle sent: > Short version: Toni's proposal seems to be a Locator/ID Separation > architecture (AKA Core Edge Elimination). > > > A look-up needs to be done once per stateful session. Thereafter > > nodes inform each other of any locator changes. > > But what if both change their locators at the same time?
This would be a breakdown and a session re-establishment process would be conducted. At least one of the sides, when realizing what would have happened, would make an inicast to restore the session. > How can one node be sure a message supposedly from the other node, > regarding the other node's new locator, is authentic? First, by looking at the other node's identifier. Second, by sending a further message and receiving a reply. Third, if needed, by doing inicast. > > >> Then, for your concrete example, why do you argue that hosts > >> should do this extra work, rather than new elements in the > >> routing system such as ITRs, as in LISP, Ivip or (by some other > >> name) IRON? > > > > No extra work. Nodes will use locators for packet outreach and IDs > > for session maintenance. > > There certainly is extra work. Initially the sending host A only > knows B's Identifier, and it somehow uses this with the number > servers to get a packet to B. I am not sure how A finds out B's > locator, but it needs to find this out ASAP so it can send subsequent > packets directly to B, without relying on any other servers. When A's inicast packet reaches B, B replies with its locator directly to A. Thus, both sides get to know their ID & Loc tuples. > There are extra delays in using these number servers. Just like doing any other resolution. But in the meantime the inital packet is on its way. And when the process of resolving completes the packet will likely be closer to its destination. This moment is when the directly tending ID server gets the packet. > When B gets a packet from A, it will have A's Identifier and it may > have A's Locator - but there's no way B can trust this Locator. So > it needs to do a lookup, or whatever it is you described with number > servers, to send a packet to A, rather than to some other host which > pretends to be A. No lookup is required. B would send a further handshake reply to A. A's reply would be the proof. > > > The routing system will consist of path selection facilities that > > make use of locators. The node ID system will consist of ID > > distribution/matching servers. > > I am sure you could write this up in a way others could understand, > but it will take a few pages and probably require some diagrams. That would be nice of me. I hope the interest grows. To be continued. _______________________________________________ rrg mailing list [email protected] http://www.irtf.org/mailman/listinfo/rrg
