Short version: Fred agrees that LISP is "not really achieving a true locator/identifier split.". He also thinks that "the LISP acronym itself seems a bit misleading". I think it is very misleading.
We discuss the meaning of "EID" and whether such addresses - or any global unicast address - identifies a host or just an interface on a host. Hi Fred, Thanks for your reply, in which you wrote: > 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. Yes - all hosts and all routers except ITRs treat them the same as any other global unicast IP address. ITRs have a special algorithm for handling packets whose destination address matches an EID prefix. > IP addresses are assigned to interfaces; hence, they name an end > system *interface* and not the end system itself. A host may have multiple interfaces, but no two hosts share the same interface. So if a global unicast address IP address identifies an interface, it is also true to say that as a result of this, this IP address also identifies a host. (This is not counting anycast, of course.) > Moreover, these LISP EIDs are routable within a certain scope; even > if that scope is only node-local. I am not quite sure what you mean by "node-local" in the context of routing packets. A packet whose destination address is a LISP EID is perfectly routable anywhere in the world, assuming there are one or more Proxy Tunnel routers advertising the "coarse" prefix which covers this EID address. (In Ivip, it is DITRs advertising Mapped Address Blocks - MABs.) All the routers except ITRs use the existing algorithm they use for all other packets with global unicast destination addresses. ITRs use a second algorithm. For a full description, please see: Re: [rrg] LEIDs, SPI & ordinary IP addresses as both IDs & Locs http://www.ietf.org/mail-archive/web/rrg/current/msg06082.html > Conversely, a true identifier (like a HIP HIT) is not routable > within any scope. Yes, a HIP HIT is purely an Identifier. > So, I have to agree that LISP is not really achieving > a true locator/identifier split. OK - thanks for this. > The LISP EID IMHO would be more accurately renamed as "Endpoint > Interface iDentifier", and the LISP acronym itself seems a bit > misleading. ["iDentifeir" typo corrected.] Since a group of completely different architectures (Core-Edge Elimination) do, as the central element of their architecture, implement the "Locator / Identifier Separation" naming model (which predates "LISP) I regard LISP's current name as being completely misleading and a source of difficulty for anyone trying to understand the "LISP" architecture, or the entire scalable routing field. To call what is currently known as a "LISP EID" address as: Endpoint Interface iDentifier wouldn't make much sense to me, since this description also fits any global unicast address which a host is using, or any other address such as an RFC 1918 or RFC 4193 ULA address which also identifies a host interface, and therefore also a host. In Ivip, I chose the term "Scalable PI" (SPI) address for the new "edge" subset of the global unicast address space which can scalably provide provider-independent address space to end-user networks for the purposes of portability, multihoming, inbound TE and mobility. I don't have a particular term for the remainder, which remains as "core" space, according to the meaning of "Core-Edge Separation". Since Ivip doesn't slice up SPI space into prefixes, there's no such thing as an SPI prefix - other than a Mapped Address Block, which is the DFZ-advertised prefix covering a block of SPI space. I use a term first used by Bill Herrin - "micronet" - to refer to the integer number of contiguous IPv4 addresses or IPv6 /64s which all have the same mapping. I think the terms LISP, EID and RLOC are confusing. "Proxy Tunnel Router" is a poor term too, since it doesn't proxy for anything. The term "LISP" (Locator Identity Separation Protocol) is really muddying the waters and I think the field and the "LISP" architecture would be much better off if it had a new name. Perhaps I will refer to it as: "the architecture which, ideally, would be formerly known as LISP" - Robin _______________________________________________ rrg mailing list rrg@irtf.org http://www.irtf.org/mailman/listinfo/rrg