In einer eMail vom 21.06.2008 05:02:19 Westeuropäische Normalzeit schreibt [EMAIL PROTECTED]:
Hi Tony and Lixia, You - or at least Tony - seem to be focusing on Getting It Right for the long-term: forever. This surely requires a clean-slate approach, with an entirely new routing and addressing architecture. Robin, Yes !!! Be assured, myself, I am also and only focused on a long-term solution, i.e. on a forever scaling solution. At the same time I never was opposed to LISP or whichever map-encap variant if considered to be a near-term interim solution.By other words: map-encap is definitely not the longterm solution. Instead I am convinced that topology aggregation will become the longterm solution because it would scale even if the internet became bigger than the network of our roads and streets. For clarity reasons, I would like to ask for using a clean taxonomy. Obviously, the term "topology aggregating prefixes" relates to prefixes that summarize DFZ-routers' addresses. I think this only fosters confusion, as all map-encap solutions are strictly in opposition to a Topology Aggregating Routing Architecture. Heiner Yes, it would create an even more complex status quo, but that wouldn't have mattered much Perhaps you could start with IPv6 and make radical changes along the lines of GSE - but the result would be something quite different from IPv6 and would involve major changes to host stacks and applications, and I guess to TCP, UDP, SCTP etc. The most substantial solutions to the routing scaling problem proposed so far are: LISP-NERD LISP-ALT APT Ivip TRRP Six/One Router These are all intended by their developers to work for both IPv4 and IPv6 as we know them today, without any host changes - other than perhaps minor optional changes to help work around moderate inherent performance problems in the pull-based map-encap systems. (I think Six/One Router can't work for IPv4, but it is intended to.) If you want the RRG to work solely on the Long Term Clean Slate approach, that is fine. While I (and I guess the other map-encap developers) would have something to contribute to that project, it is not an urgent project - unless perhaps you want it to be the only solution, which would make it much more urgent. It would take many years to devise the optimal Clean Slate approach. As part of doing so, you would need to incorporate transition mechanisms which will enable the majority of end-users to be attracted to it - even in the early days when few others use the new system - rather than keeping going with the IPv4 (or perhaps IPv6) Internet. Then it would take years to create all the new protocols in detail, write the software, get it built into existing routers and hosts, and to create new or radically re-written applications for the new system. (You would need to have a plan for motivating application programmers to make such huge investments, before many, or any, users used the new system.) A Long Term Clean-Slate project would be much more ambitious than IPng - which involved minimal changes to host stacks and applications compared to what you need to do. 12 or so years later, that project has yet to achieve success. I (and I guess the other map-encap folks) think that the current IPv4 situation is important and urgent enough to warrant an IPv4 solution first, with a similar, but not necessarily identical, solution for IPv6 to be deployed with less urgency. (I am not suggesting the Net will melt-down in 2014, just that we are so far from adopting IPv6, and that IPv6 isn't that exciting, that we need to keep IPv4 going for a lot longer so we have the decade or so it will take to devise something adoptable and long-term scalable.) All the map-encap proposals were described initially in terms of IPv4, with IPv6 details to follow later. Maybe you could get the RRG to devise a Long-Term Clean Slate you consider promising by March 2009, but I can't imagine you will convince many people that what the RRG devises is so promising that no other line of research of action needs to be taken. I think you may be able to convince some IETF folks a "Clean-Slate-only" approach was the way forward. However, I can't imagine a sufficient number of end-users and ISPs would be confident that a completely clean-slate approach would be developed, deployed and very widely adopted in time to make it unnecessary to solve the IPv4 and perhaps IPv6 scaling problems directly. The parlous state of IPv6 adoption and of its transition mechanisms shows how hard it is to migrate from IPv4 to some new network which requires different host stack and applications, and which doesn't connect directly to the IPv4 network. Your new Clean Slate approach would be even harder to migrate to, since the host stack and applications would be totally different, not just marginally different - due to your need to devise a completely different set of clearly separated identifiers, locators etc. With only 9 months to go, I think the RRG needs to decide ASAP whether we is only working on a Long-Term Clean Slate approach, or whether we are pursuing several directions of research in parallel. Until this is settled, I think we will often be discussing things at cross purposes. For instance the recent exchange between Bill and Tony, where Bill talked about the Net as it is today, and what is required to support end-users who can't and won't change from this approach in the foreseeable future, while Tony seemed to be concerned only with the Long-Term Clean Slate approach. I suggested some text - points A, B and C - we might agree to regarding multiple paths of research in a recent message: 3 potential consensus questions http://psg.com/lists/rrg/2008/msg01574.html Here are some other options if C can't be agreed to: D: No IPv4 solution - single Long-Term Solution. Devise single lasting solution which may be applicable as a major revision to IPv6 or which may require a completely new Internet architecture, protocols, applications etc. E: Devise an IPv6 solution but not an IPv4 solution. Work on a solution for IPv6 without major changes (this rules out GSE or major changes to protocol, stack, apps etc.) As this work progresses, decide whether this will be good enough for the Long Term. Either adapt it to be so, or regard scalable IPv6 as the near-term solution, while we devise a separate Long Term Clean Slate architecture. F: No IPv4 or IPv6 solution. Devise purely a Long-Term Clean Slate solution, which has no basis in IPv4 or IPv6. I like Bill Herrin's comparison with the Manhattan Project. What we are trying to do is so far from a clear solution, yet Something Definitely Needs To Be Done and there are many uncertainties about what is technically possible, and what is adoptable in various time-frames. I think there are too many uncertainties at present not to pursue multiple parallel streams of research. Maybe you only want to conduct the Long-Term stream on the RRG. - Robin
