davecb@yunexus.UUCP (David Collier-Brown) (11/17/89)
lamy@ai.utoronto.ca (Jean-Francois Lamy) writes: [about a single .ca forwarder] | Exactly. All .Ca sites get appropriate UUCP reachability data updated monthly | in the maps. Having a central .Ca forwarder for UUCP would not be such a hot | idea because | a) there are parts of the country which are completely isolated from each | other except for links through the US, and | b) The .Ca forwarder would be using the exact same data that is currently | available to all and often route back through the US, simply adding extra | hops to the route. Besides indicating that the .CA domain does not have locality of reference (:-)), this illustrates that some kinds of domains have extra requirements that do not admit to an obvious solution. Often domains, being administrative hierarchies, are assumed to be such that all their parts are "near"[1] each other. A corresponding assumption is the one that says that Usenet and BITNET are "unusual" domains because they can't have a single forwarder. Piffle. The domain mechanism, being single-dimensional, simply doesn't allow more than one mode of interpretation: one can't assume anything spacial about administrative domain nor anything administrative about spacial ones. For that reason, the whole idea of having a single forwarder for a domain approaches sillyness, and will hit it about the time a large number of .com subdomains appear. Bull[2], for example, is spread widely throughout the world, and will have to accept the necessity of providing separate forwarders on either side of a discontinuity like the Atlantic Ocean. And the need to have their name server(s) point one to different forwarders depending on where you are. In general, every subdomain that does not cluster around a point will have to do the same work that usenet already does: keep and publish a map. That the map may be provided to others by DNS does not change this. --dave [1] Where near means either spacially or temporally: I used to be near Waterloo spacially (physically), but my net got there via Phoenix AZ, so temporally I was **real** far away... Boston was closer. [2] The manufacturer, not the byproduct! -- David Collier-Brown, | davecb@yunexus, ...!yunexus!davecb or 72 Abitibi Ave., | {toronto area...}lethe!dave Willowdale, Ontario, | Joyce C-B: CANADA. 416-223-8968 | He's so smart he's dumb.