Pekka, >-----Original Message----- >From: Pekka Nikander [mailto:[email protected]] >Sent: Thursday, January 08, 2009 2:44 AM >To: Templin, Fred L >Cc: Henderson, Thomas R; RRG; Robin Whittle >Subject: Re: [rrg] Rejecting all but Strategy A > >> Regarding HIP + map/encaps, maybe it is obvious to everyone >> else already but I think what that gives you is an endpoint >> identity (the HIT), an inner routing locator (iRLOC), and an >> outer RLOC (oRLOC). Up to now, LISP (and perhaps others) have >> been using the term "EID" to refer to what I mean by "iRLOC", >> and the term "RLOC" to refer to what I mean by "oRLOC". > >That is my basic model as well. Further, as Brian observed, that can >be applied recursively.
Yes. One small but important distinction though is that recursion is not meaning to say that there would be recursive encapsulations (i.e., IP0-in-IP1-in-IP2-in ... in-IPN); else we would eat ourselves out of MTU in a hurry. Rather, we can talk about recursive RE-encapsulations. So, the initial encapsulation would be: HIT-in-iRLOC-in-oRLOC0. The packet would be forwarded within the scope within which oRLOC0 is routable, then decapsulated and re-encapsulated as HIT-in-iRLOC-in-oRLOC1. The packet is then forwarded within the oRLOC1 scope, then re-encaps'd as HIT-in-iRLOC-in-oRLOC2, etc. etc. It is exactly analogous to the way the L2 destination is changed on each IP forwarding hop without the L3 destination address changing. The only difference is that the outer IP protocol is seen as L2 by the inner IP protocol. That is one of the benefits of viewing the routing region in which oRLOCs are valid as an NBMA link over which packets of the inner IP protocol are forwarded, but there is much more to it than just this. Thanks - Fred [email protected] >But then there are a few variations. > >1. In the case of pure host-based HIP, there is no iRLOC but only the >HIT: > > HIT -> oRLOC. > >2. In the case of host-based HIP and HIP MR, the mapping is HIT -> >iRLOC -> oRLOC, which can be applied recursively leading to: > > HIT -> LOC0 -> LOCi -> LOCn. > >3a. In the case of legacy hosts and HIP proxy, for IPv6 you *can* make >iRLOC == HIT (which is what we did in the first HIP proxy work, >described in Patrik's thesis): > > iRLOC == HIT -> oRLOC > >3b. Alternatively, you can make HITs and iRLOCs separate, as you need >for IPv4 anyway: > > iRLOC <-> HIT -> oRLOC > >Generalising, we get two cases: > >a) host-based HIP generalised: HIT -> LOC0 -> LOCi -> LOCn > >b) proxy HIP generalised: iRLOC <-> HIT -> LOC0 -> LOCi -> LOCn > >In the latter case, the HIT can be "virtual" or "imaginary", if so >desired. (See my previous message.) > >> In this sense, "oRLOC" is routable within the scope of an >> interdomain region, while "iRLOC" is routable only within and >> end site (or edge network, or whatever you want to call it). >> The HIP HIT is not routable within any scope so it is purely >> an identifier and not a locator. > >That is the theory. As I noted above, for IPv6 you can make HIT == >iRLOC if you want. That is, the format allows that. > >--Pekka _______________________________________________ rrg mailing list [email protected] https://www.irtf.org/mailman/listinfo/rrg
