Hi Lixia, Thanks for pointing out (in an off-list message) that I had mischaracterised the goals of "Aggregation with Increasing Scopes: An Evolutionary Path Towards Global Routing Scalability".
I wrote (msg05835) that this proposal was aimed at "Improving router utilization as a prelude to adopting a solution". My description in msg05835 was also inaccurate except for my note that it: suggests it is near-term preliminary to a longer-term host-based solution - implicitly a Core-Edge Elimination scheme. This is based on this passage from the PDF version of the proposal: Note that our proposal neither interferes nor prevents any revolutionary host-based solutions such as ILNP from being rolled out. However, host-based solutions do not bring useful impact until a large portion of hosts have been upgraded. Thus even if a host-based solution is rolled out in the long run, an evolutionary solution is still needed for the near term. I apologise for these misleading descriptions, which were based on only partially reading the proposal. The RRG Report mentions only two of the three documents: The Virtual Aggregation presentation: http://tools.ietf.org/agenda/76/slides/grow-5.pdf The ID: http://tools.ietf.org/html/draft-zhang-evolution-02 but does not mention the PDF file: http://www.ietf.org/mail-archive/web/rrg/current/pdfkyygpVszbl.pdf which was posted to the list in (msg05550). The RRG wiki link is only to the PDF file. Due to caching constraints, I do not plan to read these fully until I have tackled the other proposals. Based on my partial reading, here are some questions which I hope you will be able to answer: 1 - What are the goals of AIS? How many non-mobile end-user network prefixes do you plan the system to scale to? Brian Carpenter and I have both, independently, suggested that 10 million such networks should be a goal. I think we must all expect that in the foreseeable future - to 2020 or 2025 - that the majority of hosts will be mobile hand-held devices. There really needs to be a mobility system so they can continue their sessions despite gaining and losing multiple addresses in various access networks - including IPv4 addresses behind NAT, such as by using WiFi in homes and offices. I think we should consider 10 billion of these the upper limit. "Mobility" is not mentioned in your proposal. To what extent is AIS intended to support large-scale mobility? 2 - How does AIS support multihoming? The word does not appear in the proposal documents or the summary. How does the multihoming support detect failure of the link between one ISP and the end-user network while detecting that the link from a second ISP is working, and that the second ISP itself is reachable? How is this information relayed to or discovered by, the routers (APRs?) which tunnel traffic packets to "egress routers"? 3 - APRs (Aggregation Point Routers) tunnel traffic packets to "egress routers". How many APRs and "egress routers" would there be? Where would they be? How do the APRs know where all the "egress routers" are, how they may appear or disappear, and be reachable or not? What tunneling protocol do you intend to use? I assume it would be an entirely ad-hoc arrangement rather than having to maintain two way tunnels to each "egress router". 4 - How will you handle Path MTU Discovery in the tunnels from APRs to "egress routers"? At present, I think my IPTM technique [1] and Fred Templin's SEAL [2] are the only protocols which can handle this, though IPTM is Ivip-specific. Both of them aim to cope with jumboframes as DFZ paths for these develop in the future. LISP's approach to PMTUD [3] is not fully developed, and does not send a PTB to the sending host until a second too-big packet arrives. It needs to be elaborated with checking for an increased PMTU every 10 minutes or so. 5 - I understand that some or ultimately all ISPs would run APRs. I assume that when all ISPs run APRs that this will enable the removal of end-user network prefixes from the DFZ. When only some ISPs run them, is there any prospect for reducing the number of prefixes advertised in the DFZ? If so then how would end-user networks whose prefixes were removed receive packets sent by hosts using ISPs without APRs? 6 - What advantage would ILNP or any other CEE architecture provide compared to a fully deployed version of AIS? 7 - Do you consider a full AIS deployment to be a Core-Edge Separation architecture, in that it creates a subset of the global unicast address space? 8 - Why would AIS, or AIS supplemented by a CEE architecture, be better than LISP or Ivip? (I do not consider TIDR to be a solution because it uses DFZ routers for mapping distribution. I don't yet understand RANGER, but perhaps it too does this.) - Robin [1] http://www.firstpr.com.au/ip/ivip/pmtud-frag/ [2] http://tools.ietf.org/html/draft-templin-intarea-seal-08 [3] http://tools.ietf.org/html/draft-ietf-lisp-06#section-5.4.2 _______________________________________________ rrg mailing list [email protected] http://www.irtf.org/mailman/listinfo/rrg
