On Mon, 17 Oct 2005, Tony Li wrote:
True. Even better, you get to change this binding (mobility) or have multiple bindings (multihoming).
Indeed.
True enough, but unfortunately, it's not done in a way that we can make use of the identifier in the routing subsystem or in the transport protocols.
Well, if the idea is that the global routing subsystem should not have to burdened with the overwhelming details of "who"->"where", then this mightn't matter much - all routing needs to know is "where". The transport protocols, well they generally act on behalf of something which can do the lookup and supply transport with right address, as long the DNS server does not require "who"->"where" indirection ;). The other way of course is to carry "who"->"where" as routes in our current routing system. Then we just have to figure out how to confine things topologically. Would require changes in how providers peer though, but it is possible. And has been done in other networks, eg GSM in Ireland. We have provider-assigned, but provider-mobile prefixes. Just as with IP multihoming there was much protest that it couldn't be done, would be too problematic, would be too burdensome. However the regulator told the operators "I don't care, you have till X to figure it out and implement". The operators did figure out, presumably including how to do billing for the differentials of any traffic carried for customers who had moved to other providers... The rest of the world has no clue that a large set of Irish GSM telephone numbers are essentially "/32 routed" between Irish providers. ;) A possibility anyway (but whether it's the least worst way - i don't know ;) ). It does though keep operators fully involved in all aspects of routing. Otherwise end-hosts will just work around the 'dumb' providers themselves, if there's no solution operators like. (Not a bad thing either really).
Tony
regards, -- Paul Jakma paul@clubi.ie paul@jakma.org Key ID: 64A2FF6A Fortune: Money isn't everything -- but it's a long way ahead of what comes next. -- Sir Edmond Stockdale