It's fairly clear that architecturally, IPv4 and IPv6 are at exactly the same place on this: the notions of identifier and locator are 100% overlaid on each other. So in practical terms - what can we do, and standardize, *today* - we simply can't make the distinction.
The IRTF NameSpace research group has been working inconclusively on the architectural issue for a couple of years. See http://www.ietf.org/internet-drafts/draft-irtf-nsrg-report-01.txt for a snapshot. imho it is best to disregard the philosophical side if you want to make progress immediately. What's the practical issue with embedding the home address in such a routing header? Brian Pekka Nikander wrote: > > Hello all, > > Related to the debate on the mobile-ip list on whether > MIPv6 should use Routing Header or some other mechanism > to carry the home address to a mobile node that is > away from home, I'd like to solicit for well grounded > opinions on the intended semantics of the Routing Header. > > To properly understand what I am really asking about we > must first make a distinction between two logical > entities, endpoints and locations. In the current > Internet architecture, both endpoints and locations are > identified with a single mechanism, i.e. with IP addresses. > However, they are conceptually different, as very well > pointed out by Noel Chiappa in > http://users.exis.net/~jnc/tech/endpoints.txt > In essense, a communication endpoint is an active > entity engadged in the communications, i.e. a party > who consumes messages and generates new ones. A location, > on the other hand, is a topological "place" within the > routing fabric. > > Now, my question is fairly simple: Is the meaning of > the routing header to allow a packet to be sent through > a number of communicating hosts (end-points) or via a > specific path, identified by a set of locations? Or > is it both? > > One way of pondering the question is to imagine that the > endpoints and locations had different name spaces. For > example, you could imagine that each host has a flat > name tag (HIT in HIP terminology), and the locations > are named according to the routing hierarchy as today. > Under such an architecture, would the routing header > contain addresses or these new name tags, or could > it contain a mixture of both? > > The reason why I am asking this is the scenario, which > Charlie Perkins has offered, where a packet is source > routed through a Mobile Node that is away from home. > According to his argumentation, in such case the > routing header should have a route looking like > > .... - Care-of-Address - Home Address - .... > > where the Care-of-Address is the current location of > the mobile node, and the Home Address is more like > the end-point identifier of the mobile node. I am > having hard time in clearly crasping the intended > semantic meaning of this construction. > > --Pekka Nikander -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
