Lloyd - >Couldn't this document be effectively combined with >draft-ymbk-arch-guidelines-05.txt >(also headed for informational) > >to make a much more comprehensive document that starts frmo RFC1958 >and builds up? I don't think so, actually. draft-iab-considerations-02.txt is rather different from RFC1958 and draft-ymbk-arch-guidelines-05.txt in that draft-iab-considerations-02.txt largely poses questions to be asked, without necessarily giving answers, while the other two documents are more oriented towards giving guidelines and principles. One could argue that these are just differences in style, but I don't think that is the case. I think there is a useful place for stating questions that we know are important questions, without making too many claims about knowing the answers to the questions. Our draft draft-iab-considerations-02.txt does have a section about draft-ymbk-arch-guidelines-05.txt, and the related paper by Willinger and Doyle on "Robustness and the Internet: Design and Evolution", in Section 13.3 on "Discussion: complexity, robustness, and fragility"; I happen to be a particular fan of the Willinger and Doyle paper. That does not mean, however, that I agree with it, or with draft-ymbk-arch-guidelines-05.txt; my own view, which I have communicated privately to the authors of both documents, are that both documents are a touch one-sided, seeing the great problems introduced by added complexity, but not always seeing the sometimes-compelling motivations behind that added complexity. (I am particularly aware of the benefits when it comes to TCP, which is the area where I have been involved in adding complexity for some time now...) The challenge, it seems to me, is how to accommodate added complexity when it is sufficiently compelling, while minimizing the fragility and overhead that might go along with that added complexity. This means that, while I find draft-ymbk-arch-guidelines-05.txt useful and interesting, I personally disagree with some of it. For example, about layering, I think that layering is sometimes one of the properties that allows complexity with robustness instead of fragility, and that very careful, explicit, and conscious communication between layers, when necessary, might be one of the strategies that allows layering to work. This is different from the conclusions in draft-ymbk-arch-guidelines-05.txt. And some parts of draft-ymbk-arch-guidelines-05.txt, e.g., the later parts on packet vs. circuit switching, or the parts on the relationship between complexity and the capital and operational expenditures for carrier IP networks, are quite different in topic from draft-iab-considerations-02.txt, and properly belong in an individual submission rather than a document from the IAB (in my opinion). And those are just my own private opinions. I don't know what all of the opinions would be from the other IAB members. I don't see that it is necessary (or that it would be productive or useful) to attempt an IAB-wide consensus, or an IETF-wide consensus, on all of the issues in draft-ymbk-arch-guidelines-05.txt. Though the IAB *is* mulling over the idea of where to go next in terms of discussions of the overall architecture... - Sally http://www.icir.org/floyd/