Robin, As I have said many times here on the list, what LISP is calling "EID" is nothing more and nothing less than an IP address. IP addresses are assigned to interfaces; hence, they name an end system *interface* and not the end system itself. Moreover, these LISP EIDs are routable within a certain scope; even if that scope is only node-local. Conversely, a true identifier (like a HIP HIT) is not routable within any scope.
So, I have to agree that LISP is not really achieving a true locator/identifier split. The LISP EID IMHO would be more accurately renamed as "Endpoint Interface iDentifeir", and the LISP acronym itself seems a bit misleading. Fred fred.l.temp...@boeing.com > -----Original Message----- > From: rrg-boun...@irtf.org [mailto:rrg-boun...@irtf.org] On Behalf Of Robin > Whittle > Sent: Tuesday, March 09, 2010 7:21 PM > To: RRG > Cc: Scott Brim > Subject: Re: [rrg] LISP does not implement Locator / Identity Separation > > Short version: One of the most important benefits of the "LISP" > architecture (or any other CES architecture) is that > it does *not* involve hosts using "Locator / > Identifier Separation". > > I suggest renaming the "LISP" architecture - to > avoid the confusion caused by its current name. > > > Hi Scott, > > Thanks for your reply, in which you wrote: > > >> An EID address is not an Identifier and an RLOC > >> address is not a Locator. Both kinds of address > >> are like any IP address - they play the roles of > >> both Identifier and Locator. ITRs use a different > >> algorithm for EID destination addresses. All > >> other routers and all hosts make no distinction > >> between EID and RLOC addresses. > > > > Give up on the names and look at how things are used. As to whether > > something "is" an identifier or not, the main question is NOT whether it > > is sometimes used by forwarding functions (forwarders already use > > anything and everything they want to make forwarding decisions), but > > whether its association with a particular endpoint (at some layer) is > > independent of changes in topology. > > Both EID and RLOC addresses function as Identifiers - I am not > suggesting that an EID address doesn't. > > I am suggesting that an EID address in the destination field also > acts as a routing Locator, since it is used in exactly the same way > as any other kind of address by all hosts and routers except ITRs. > ITRs use it as a routing locator too, but with a second algorithm > which uses the mapping system and tunneling. I explained this in the > original message: > > http://www.ietf.org/mail-archive/web/rrg/current/msg06190.html > > I previously noted (msg06202) that the first sentence above should > have been: > > An EID address is not only an Identifier and an RLOC address is > not only a Locator. > > > > In the case of LISP the answer is not clear because it depends on use. > > Potentially it can be topology-independent, but it is expected to be > > used by forwarding in some site deployments, and a site might renumber > > endpoints within an EID prefix if they move within that site. > > > > But really, the thing to focus on is expected usage and real world usage. > > "Locator / Identifier Separation" is an enormously important > architectural concept which pre-dates "LISP". It concerns hosts > dealing with other hosts by two separate types of object: Identifiers > to uniquely identify a host (though a host could have more than one > Identifier) and Locators to control how a packet gets to the > destination host. It affects packet addressing structures, host > stacks and typically applications. (Loc/ID Separation architectures > which attempt to support un-modified applications are pretty dodgy, I > think, since the applications make assumptions about the IP addresses > they use which are hard to support with the Loc/ID Separation stack > and network.) > > Your architecture does not implement "Locator / Identifier > Separation" at a host level - which is what the term has always > referred to. You could argue that this concept is at work in the > ITR's algorithm, but that is unimportant to hosts - and hosts are the > most important things in the Net. > > I think this field has suffered considerable confusion due to your > architecture being named after "Locator / Identifier Separation" - > and due to continued claims that it really does support this Loc/ID > Separation naming model. > > I suggest you rename your proposal. This would save a great deal of > confusion when people try to understand it. > > Your architecture is completely different from the Locator / > Identifier Separation architectures such as HIP, GSE, ILNP, > Name-Based Sockets, RANGI and GLI-Split. Your architecture is a > Core-Edge Separation architecture, which is a very good thing. > > One of the most important benefits of your architecture (or any other > CES architecture) is that it does *not* involve hosts using "Locator > / Identifier Separation". > > - Robin > > _______________________________________________ > rrg mailing list > rrg@irtf.org > http://www.irtf.org/mailman/listinfo/rrg _______________________________________________ rrg mailing list rrg@irtf.org http://www.irtf.org/mailman/listinfo/rrg
