"The IETF has difficulty solving complex problems"
Scott W Brim <sbrim@cisco.com> Thu, 04 August 2005 05:05 UTC
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Date: Thu, 04 Aug 2005 07:05:04 +0200
From: Scott W Brim <sbrim@cisco.com>
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Subject: "The IETF has difficulty solving complex problems"
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This conjecture was disturbing, but calling it a feature was even more disturbing. After a bit of pondering, and wondering what different groups in the IETF might mean by "complex", my first thought was that the IETF has never, ever solved one. For example, we do QoS in small pieces that don't fit together well. Some claim that CIDR was such a solution but imho it was just a tweak on what we already had. Our routing protocols have been fertile ground for evolution but not revolution -- the path vector idea came directly from deprecating EGP "metrics", we still aren't very stable and our policy capabilities are frustrating. However, after talking to a few people I thought that perhaps we are very good at solving complex problems but we don't recognize our greatness. Again let me take QoS as an example. The problem is huge and essentially intractable because of all the competing goals. What we have done, without a lot of architectural planning that I am aware of, is to find ways to divide the problem up where there is minimum coupling across the boundaries (see footnote (*)). That lowers the complexity greatly. It is a lot cheaper to have independent, apparently "unarchitected" solutions for different kinds of traffic and situations. I want us to understand what our skills are and use them consciously. I don't know if we will have time tonight, but I'd like to hear from the IESG/IAB on the foundation for Brian's statement and what was initially a negative assessment of our skill. Let's look at some example problems and think about what we have done poorly and well. I predict we are better than we think, but that we are hard to satisfy. We may think of some of the things we have done as crude hacks but they are actually pretty good solutions. Look at tunnels, for example. They are kind of abhorrent when thought of in isolation but turn out to be an appropriate means to reduce complexity in specific situations. Reducing complexity through cutting up the problem at the right points is implicit now. We could make it one of our explicit basic paradigms. As a corollary to making it explicit, we should be aware of where we use this kind of decoupling and be vigilant about it. Some users of the IETF "product set" want to reintroduce coupling that we have eliminated. Be sure the trade-offs are explicitly examined. swb (*) like Chuang Tzu's butcher ... "The joints have openings, And the knife's blade has no thickness. Apply this lack of thickness into the openings, And the moving blade swishes through, With room to spare! _______________________________________________ Ietf mailing list Ietf@ietf.org https://www1.ietf.org/mailman/listinfo/ietf
- "The IETF has difficulty solving complex problems" Scott W Brim
- Re: "The IETF has difficulty solving complex prob… JFC (Jefsey) Morfin
- RE: "The IETF has difficulty solving complex prob… Hallam-Baker, Phillip
- Re: "The IETF has difficulty solving complex prob… Brian E Carpenter
- Re: "The IETF has difficulty solving complex prob… JFC (Jefsey) Morfin
- Re: "The IETF has difficulty solving complex prob… Pekka Nikander
- Re: "The IETF has difficulty solving complex prob… Richard Shockey
- Re: "The IETF has difficulty solving complex prob… Spencer Dawkins
- Re: "The IETF has difficulty solving complex prob… Richard Shockey
- Re: "The IETF has difficulty solving complex prob… Harald Tveit Alvestrand
- Re: "The IETF has difficulty solving complex prob… Jari Arkko
- Re: "The IETF has difficulty solving complex prob… Henning Schulzrinne
- Re: "The IETF has difficulty solving complex prob… Harald Tveit Alvestrand
- Re: "The IETF has difficulty solving complex prob… Masataka Ohta
- Re: "The IETF has difficulty solving complex prob… Pekka Nikander
- Re: "The IETF has difficulty solving complex prob… Iljitsch van Beijnum
- Re: "The IETF has difficulty solving complex prob… Pekka Nikander
- Re: "The IETF has difficulty solving complex prob… JFC (Jefsey) Morfin
- Re: "The IETF has difficulty solving complex prob… Pekka Nikander
- HIP new possibilities JFC (Jefsey) Morfin
- Re: "The IETF has difficulty solving complex prob… Iljitsch van Beijnum
- Re: "The IETF has difficulty solving complex prob… Pekka Nikander