From craig at aland.bbn.com Mon Dec 1 05:48:21 2008 From: craig at aland.bbn.com (Craig Partridge) Date: Mon, 01 Dec 2008 08:48:21 -0500 Subject: [e2e] a means to an end In-Reply-To: Your message of "Thu, 06 Nov 2008 16:20:42 EST." <49135FAA.6080603@reed.com> Message-ID: <20081201134821.77EE428E155@aland.bbn.com> >Our dear friend, Van Jacobsen, has decided that layering "where" under >"what" with regard to data is neither necessary, nor a good idea. > >I agree: confusing the container with the information it happens to hold >is a layer violation. Information is not bound to place, nor is there a >primary instance. Information is place-free, and perhaps the idea that >there must be a "place" where it "is" is an idea whose time should pass, >and the purveyors of that idea as a holy writ (the OSI layering) retired >to play golf. Hi Dave: Much as I'd like to believe this particular theory (as it is nice, clean and pretty), practical considerations suggest we're not there. I've talked with some of the folks working on information and seeking to make information place-free, and the answer, so far, that I've gotten is that you get part-way there. If the information is popular or "nearby" then there are mechanisms that can be viewed as place-free (and a good thing -- it means that the more popular a piece of information is, the easier to get easily and perhaps from somewhere locally). But if you ask about retrieving an uncommon piece of information then you discover "location" crawls out from under the covers. That is, if you ask the question "where do I find the sole copy of item X", you learn that somewhere hidden in the name of X is a location -- perhaps of X or perhaps of a rendezvous server that knows where X is -- but there's the location of something buried in there. Thanks! Craig From kurt.tutschku at univie.ac.at Mon Dec 1 07:25:47 2008 From: kurt.tutschku at univie.ac.at (Kurt Tutschku) Date: Mon, 1 Dec 2008 16:25:47 +0100 Subject: [e2e] Two weeks to go: 20th ITC Specialist Seminar on NETWORK VIRTUALIZATION Message-ID: <7009F8A9-2C79-4DB6-B393-66C266B5CB8D@univie.ac.at> ********************************************************************************** 3nd Call-for-Paper UPDATE: Submission site is on-line 20th ITC Specialist Seminar on NETWORK VIRTUALIZATION ? Concepts and Performance Aspects http://www.itcspecialistseminar.com/itcss20/ 18.-20. Mai 2009 Swiss-Belhotel Golden Sand Resort, Hoi An, Viet Nam ********************************************************************************** AIMS AND TOPICS Network virtualization is the technology that allows the simultaneous operation of multiple logical networks (also known as overlays) on a single physical platform. Network virtualization permits distributed participants to create almost instantly their own network with application-specific naming, routing, and resource management mechanisms. For instance, server virtualization enables users to use parts of a computing center as their own personal computer. Recently, network virtualization received tremendous attention since it is expected to be one of the major paradigms for the future Internet as proposed by numerous international initiatives on future networks, e.g. PlanetLab (USA, International), GENI (USA), AKARI (JAPAN), OneLab2 (Europe), and G-Lab (Germany). A major objective of this ITC Specialist Seminar is to early identify future performance issues and to provide methodologies and mechanisms to address the various performance problems in network virtualization. The seminar is intended as a forum for scientists and engineers in academia and industry to exchange and discuss their latest experiences and research results. It will address techniques, architectures, performance models, and performance engineering methods leading to real world network virtualization solutions that provide users with efficient techniques for creating and operating their own high performance virtual network. Topics of interest are amongst others, but not limited to: o Performance issues of virtualization techniques on routers and end hosts o Performance issues of bandwidth and resource virtualization techniques o Performance issues of overlays for future network architectures o Performance of virtualized transport mechanisms o Performance of virtualized services and virtualized applications o Virtual test labs and network federation KEYNOTES AND INVITED TALKS The organizers of the seminar are proud to announce the following keynote and invited speakes: o Keynote: Prof. H. Kobayashi (Sherman Fairchild University Professor Erimitus of Electrical Engineering and Computer Science and former Dean of the School of Engineering and Applied Science (SEAS), Princeton University, USA) o Invited Talk: Prof. A. Nakao (Head of the Network Virtualization Laboratory of NICT, Japan and Associate Professor at the Graduate School of Interdisciplinary Information Studies, The University of Tokyo) IMPORTANT DATES Submission deadline: December 15, 2008 Acceptance notification: January 31, 2008 Camera ready: February 20, 2008 SUBMISSION SITE http://www.easychair.org/conferences?conf=itcss20 (Please follow instructions at http://www.itcspecialistseminar.com/author.php ) PUBLICATION All papers will be published in the workshop proceedings. In addition, selected papers will be invited for being published as an extended version in a special issue on "Network Virtualization" of the International Journal of Communication Networks and Distributed Systems (IJCNDS, http://www.inderscience.com/browse/index.php?journalCODE=ijcnds) GENERAL CHAIR o Phuoc Tran-Gia, University of Wuerzburg, Germany GENERAL CO-CHAIR o Prosper Chemouil, Orange Labs, France TPC CHAIRS o Kurt Tutschku, University of Vienna, Austria o Paul Mueller, University of Kaiserslautern, Germany o Frederic Dang Tran, France Telecom Orange Group, France PUBLICITY CHAIR o Rastin Pries, University of Wuerzburg, Germany TPC o Stephan Baucke, Ericsson Research, Germany o Andy Bavier, Princeton University, USA o Hans van den Berg, TNO and Twente University, Netherlands o Marcus Brunner, NEC, Germany o Joachim Charzinski, Nokia Siemens Networks, Munich, Germany o Omar Cherkaoui, University of Quebec in Montreal, Canada o Nguyen Dai Tho, College of Technology, Ha Noi National University, Viet Nam o Hoang Dang Hai, Ministry of Information and Communications, Viet Nam o Serge Fdida, Universite Pierre & Marie Curie, Paris, France o Markus Fiedler, Blekinge Tekniska H?gskola, Karlskrona, Sweden o Carmelita Goerg, University of Bremen, Germany o JongWon Kim, Gwangju Institute of Science and Technology, Gwangju, Korea o Ulf Koerner, Lund University, Sweden o Daniel Kofman, ENST/INFRES/RHD, Paris, France o Paul Kuehn, University of Stuttgart, Germany o Kenji Leibnitz, Osaka University, Osaka, Japan o Laurent Mathy, Lancester University, Lancester, United Kingdom o Deep Medhi, University of Missouri - Kansas City, Kansas City, MO, USA o Michael Menth, University of Wuerzburg, Germany o Masayuki Murata, Osaka University, Osaka, Japan o Akihiro Nakao, The University of Tokyo/NICT, Tokyo, Japan o Nguyen Ngoc Binh, College of Technology, Ha Noi, Viet Nam o Guy Pujolle, LIP6, France o Dario Rossi, ENST Telecom Paris, France o Hiroshi Saito, NTT, Tokyo, Japan o Moshe Sidi, Technion, Haifa, Israel o Ralf Steinmetz, University of Darmstadt, Germany o Martin Stiemerling, NEC, Heidelberg, Germany o Pascale Vicat-Blanc Primet, Inria, France LOCAL ORGANIZATION CHAIR o Nguyen Tien Dzung, Ha Noi University of Technology, Ha Noi, Viet Nam o Nguyen Huu Thanh, Ha Noi University of Technology, Ha Noi, Viet Nam o Vu Duy Loi, College of Technology, Ha Noi, Viet Nam o Nguyen Ngoc Hien, College of Technology, Ha Noi National Unversity, Viet Nam o Nguyen Dinh Viet, College of Technology, Ha Noi National Unversity, Viet Nam o Doan Minh Phuong, College of Technology, Ha Noi National Unversity, Viet Nam o Nguyen Minh Tri, College of Technology, Ha Noi National Unversity, Viet Nam o Duong Ba Hong Thuan, Ha Noi University of Technology, Viet Nam o Nguyen Huyen Trang, Ha Noi University of Technology, Viet Nam --- Prof. Dr. Kurt Tutschku Chair of Future Communication (Endowed by Telekom Austria) Institute of Distributed and Multimedia Systems, Faculty of Computer Science University of Vienna, Universitaetsstrasse 10/T11, 1090 Wien, Austria. Tel: +43/1/4277-39611 mailto:kurt.tutschku at univie.ac.at or mailto:kurttutschku at gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.postel.org/pipermail/end2end-interest/attachments/20081201/3210bc53/attachment-0001.html From dpreed at reed.com Mon Dec 1 07:55:46 2008 From: dpreed at reed.com (David P. Reed) Date: Mon, 01 Dec 2008 10:55:46 -0500 Subject: [e2e] a means to an end In-Reply-To: <20081201134821.77EE428E155@aland.bbn.com> References: <20081201134821.77EE428E155@aland.bbn.com> Message-ID: <49340902.2050400@reed.com> Interesting. Your presumption that information is a matter of copies, and that "sole copy" is a well-defined term, suggests a fundamental difference in our understanding of the word "information". Had you used the word "datum" or "message" (two human constructed concepts), I might agree. But "information" is not a synonym for either term. Both are *representations* or *instantiations* of information. A piece of paper with a number printed on it may be the "sole instance" of a printed piece of paper with that particular representation of information. But if that number represents (say) "the total net value of my bank account on Dec. 1 2008", it is not at all the only "copy" of information. Information typically exists independent of form or representation. It is a constructed, calculated, computed thing. It doesn't exist independently, nor does it exist in sole form. Yes, I could agree with you that if information were forced to exist in "single copy" form, it would require some complex and amazing procedure to copy that piece of information into another place. But, once copied, it would be smeared across half the universe. (or alternatively you could decide, since "place" is really not a very easy-to-define term, that the information is still in one place, but the universe has now collapsed significantly, because all the places "containing" (whatever that means) the information would be "the same place"). But independent of that: why is any information system designed to have data in a "sole copy"? Van asks this question, and he is wise to ask this question. Most computer systems work by having vast numbers of copies of data. We constantly see most information representations used in computation in the form of cached data. It seems to me that it is a pure fetish, perhaps conditioned by training, to posit that most information is represented by single copies. That way lies "brittle" failure-prone engineering. Let a thousand representations bloom. Many of them will be copies of a datum. Others will be computable recovery algorithms - some of which invent an abstraction called "location". But even that abstraction called location is not a "place" in the sense of a 4 dimensional spatial metric based coordinate system. I address a piece of paper by its title, not its current location in the file folder on someone's desk. Craig Partridge wrote: >> Our dear friend, Van Jacobsen, has decided that layering "where" under >> "what" with regard to data is neither necessary, nor a good idea. >> >> I agree: confusing the container with the information it happens to hold >> is a layer violation. Information is not bound to place, nor is there a >> primary instance. Information is place-free, and perhaps the idea that >> there must be a "place" where it "is" is an idea whose time should pass, >> and the purveyors of that idea as a holy writ (the OSI layering) retired >> to play golf. >> > > Hi Dave: > > Much as I'd like to believe this particular theory (as it is nice, clean > and pretty), practical considerations suggest we're not there. > > I've talked with some of the folks working on information and seeking > to make information place-free, and the answer, so far, that I've gotten > is that you get part-way there. If the information is popular or > "nearby" then there are mechanisms that can be viewed as place-free (and > a good thing -- it means that the more popular a piece of information is, > the easier to get easily and perhaps from somewhere locally). > > But if you ask about retrieving an uncommon piece of information then > you discover "location" crawls out from under the covers. That is, > if you ask the question "where do I find the sole copy of item X", you > learn that somewhere hidden in the name of X is a location -- perhaps > of X or perhaps of a rendezvous server that knows where X is -- but > there's the location of something buried in there. > > Thanks! > > Craig > > From craig at aland.bbn.com Mon Dec 1 08:53:29 2008 From: craig at aland.bbn.com (Craig Partridge) Date: Mon, 01 Dec 2008 11:53:29 -0500 Subject: [e2e] a means to an end In-Reply-To: Your message of "Mon, 01 Dec 2008 10:55:46 EST." <49340902.2050400@reed.com> Message-ID: <20081201165329.6954028E161@aland.bbn.com> Hi Dave: So fine, call it datum or message -- the point is that some things that are desired have a single current instance. That instance may get replicated eventually, or not, depending on context. It may be that you can retrieve something similar from other, more widely available, sources/instances/etc. But you haven't responded to the point I made which is that when you want something that is rare, what I've discovered is all systems to date embed location. If I'm understanding your note, you think I'm saying there's a reference copy/instance that we all must go back to ala the Grail (nope, that's not what I'm saying) or that I'm otherwise intentionally making things rare. Instead I'm saying, when something is rare (1 instance/instantiation/whatever in the world -- and, by the way, I care about such cases as I used to be a medievalist and occasionally was probably the first person to see a document since it was written 700 years ago), I've found that every information retrieval system (including Van's) embeds a location. Thanks! Craig In message <49340902.2050400 at reed.com>, "David P. Reed" writes: >Interesting. > >Your presumption that information is a matter of copies, and that "sole >copy" is a well-defined term, suggests a fundamental difference in our >understanding of the word "information". > >Had you used the word "datum" or "message" (two human constructed >concepts), I might agree. But "information" is not a synonym for either >term. Both are *representations* or *instantiations* of information. > >A piece of paper with a number printed on it may be the "sole instance" >of a printed piece of paper with that particular representation of >information. But if that number represents (say) "the total net value >of my bank account on Dec. 1 2008", it is not at all the only "copy" of >information. > >Information typically exists independent of form or representation. It >is a constructed, calculated, computed thing. It doesn't exist >independently, nor does it exist in sole form. > >Yes, I could agree with you that if information were forced to exist in >"single copy" form, it would require some complex and amazing procedure >to copy that piece of information into another place. But, once copied, >it would be smeared across half the universe. (or alternatively you >could decide, since "place" is really not a very easy-to-define term, >that the information is still in one place, but the universe has now >collapsed significantly, because all the places "containing" (whatever >that means) the information would be "the same place"). > >But independent of that: why is any information system designed to have >data in a "sole copy"? Van asks this question, and he is wise to ask >this question. Most computer systems work by having vast numbers of >copies of data. We constantly see most information representations used >in computation in the form of cached data. > >It seems to me that it is a pure fetish, perhaps conditioned by >training, to posit that most information is represented by single >copies. That way lies "brittle" failure-prone engineering. > >Let a thousand representations bloom. Many of them will be copies of a >datum. Others will be computable recovery algorithms - some of which >invent an abstraction called "location". But even that abstraction >called location is not a "place" in the sense of a 4 dimensional spatial >metric based coordinate system. I address a piece of paper by its >title, not its current location in the file folder on someone's desk. > > >Craig Partridge wrote: >>> Our dear friend, Van Jacobsen, has decided that layering "where" under >>> "what" with regard to data is neither necessary, nor a good idea. >>> >>> I agree: confusing the container with the information it happens to hold >>> is a layer violation. Information is not bound to place, nor is there a >>> primary instance. Information is place-free, and perhaps the idea that >>> there must be a "place" where it "is" is an idea whose time should pass, >>> and the purveyors of that idea as a holy writ (the OSI layering) retired >>> to play golf. >>> >> >> Hi Dave: >> >> Much as I'd like to believe this particular theory (as it is nice, clean >> and pretty), practical considerations suggest we're not there. >> >> I've talked with some of the folks working on information and seeking >> to make information place-free, and the answer, so far, that I've gotten >> is that you get part-way there. If the information is popular or >> "nearby" then there are mechanisms that can be viewed as place-free (and >> a good thing -- it means that the more popular a piece of information is, >> the easier to get easily and perhaps from somewhere locally). >> >> But if you ask about retrieving an uncommon piece of information then >> you discover "location" crawls out from under the covers. That is, >> if you ask the question "where do I find the sole copy of item X", you >> learn that somewhere hidden in the name of X is a location -- perhaps >> of X or perhaps of a rendezvous server that knows where X is -- but >> there's the location of something buried in there. >> >> Thanks! >> >> Craig >> >> From dpreed at reed.com Mon Dec 1 09:21:51 2008 From: dpreed at reed.com (David P. Reed) Date: Mon, 01 Dec 2008 12:21:51 -0500 Subject: [e2e] a means to an end In-Reply-To: <20081201165329.6954028E161@aland.bbn.com> References: <20081201165329.6954028E161@aland.bbn.com> Message-ID: <49341D2F.50804@reed.com> I've studied Van's and there is no "location" embedded in his system. Unless of course you redefine the word location to mean something quite different than "geographic place". Craig Partridge wrote: > Hi Dave: > > So fine, call it datum or message -- the point is that some things that > are desired have a single current instance. That instance may get replicated > eventually, or not, depending on context. It may be that you can > retrieve something similar from other, more widely available, > sources/instances/etc. > > But you haven't responded to the point I made which is that when you > want something that is rare, what I've discovered is all systems to > date embed location. If I'm understanding your note, you think I'm > saying there's a reference copy/instance that we all must go back to > ala the Grail (nope, that's not what I'm saying) or that I'm otherwise > intentionally making things rare. Instead I'm saying, when something is > rare (1 instance/instantiation/whatever in the world -- and, by the way, > I care about such cases as I used to be a medievalist and occasionally > was probably the first person to see a document since it was written 700 > years ago), I've found that every information retrieval system (including > Van's) embeds a location. > > Thanks! > > Craig > > In message <49340902.2050400 at reed.com>, "David P. Reed" writes: > > >> Interesting. >> >> Your presumption that information is a matter of copies, and that "sole >> copy" is a well-defined term, suggests a fundamental difference in our >> understanding of the word "information". >> >> Had you used the word "datum" or "message" (two human constructed >> concepts), I might agree. But "information" is not a synonym for either >> term. Both are *representations* or *instantiations* of information. >> >> A piece of paper with a number printed on it may be the "sole instance" >> of a printed piece of paper with that particular representation of >> information. But if that number represents (say) "the total net value >> of my bank account on Dec. 1 2008", it is not at all the only "copy" of >> information. >> >> Information typically exists independent of form or representation. It >> is a constructed, calculated, computed thing. It doesn't exist >> independently, nor does it exist in sole form. >> >> Yes, I could agree with you that if information were forced to exist in >> "single copy" form, it would require some complex and amazing procedure >> to copy that piece of information into another place. But, once copied, >> it would be smeared across half the universe. (or alternatively you >> could decide, since "place" is really not a very easy-to-define term, >> that the information is still in one place, but the universe has now >> collapsed significantly, because all the places "containing" (whatever >> that means) the information would be "the same place"). >> >> But independent of that: why is any information system designed to have >> data in a "sole copy"? Van asks this question, and he is wise to ask >> this question. Most computer systems work by having vast numbers of >> copies of data. We constantly see most information representations used >> in computation in the form of cached data. >> >> It seems to me that it is a pure fetish, perhaps conditioned by >> training, to posit that most information is represented by single >> copies. That way lies "brittle" failure-prone engineering. >> >> Let a thousand representations bloom. Many of them will be copies of a >> datum. Others will be computable recovery algorithms - some of which >> invent an abstraction called "location". But even that abstraction >> called location is not a "place" in the sense of a 4 dimensional spatial >> metric based coordinate system. I address a piece of paper by its >> title, not its current location in the file folder on someone's desk. >> >> >> Craig Partridge wrote: >> >>>> Our dear friend, Van Jacobsen, has decided that layering "where" under >>>> "what" with regard to data is neither necessary, nor a good idea. >>>> >>>> I agree: confusing the container with the information it happens to hold >>>> is a layer violation. Information is not bound to place, nor is there a >>>> primary instance. Information is place-free, and perhaps the idea that >>>> there must be a "place" where it "is" is an idea whose time should pass, >>>> and the purveyors of that idea as a holy writ (the OSI layering) retired >>>> to play golf. >>>> >>>> >>> Hi Dave: >>> >>> Much as I'd like to believe this particular theory (as it is nice, clean >>> and pretty), practical considerations suggest we're not there. >>> >>> I've talked with some of the folks working on information and seeking >>> to make information place-free, and the answer, so far, that I've gotten >>> is that you get part-way there. If the information is popular or >>> "nearby" then there are mechanisms that can be viewed as place-free (and >>> a good thing -- it means that the more popular a piece of information is, >>> the easier to get easily and perhaps from somewhere locally). >>> >>> But if you ask about retrieving an uncommon piece of information then >>> you discover "location" crawls out from under the covers. That is, >>> if you ask the question "where do I find the sole copy of item X", you >>> learn that somewhere hidden in the name of X is a location -- perhaps >>> of X or perhaps of a rendezvous server that knows where X is -- but >>> there's the location of something buried in there. >>> >>> Thanks! >>> >>> Craig >>> >>> >>> > > From craig at aland.bbn.com Mon Dec 1 09:32:07 2008 From: craig at aland.bbn.com (Craig Partridge) Date: Mon, 01 Dec 2008 12:32:07 -0500 Subject: [e2e] a means to an end In-Reply-To: Your message of "Mon, 01 Dec 2008 12:21:51 EST." <49341D2F.50804@reed.com> Message-ID: <20081201173207.DE7A828E155@aland.bbn.com> Hi Dave: I asked Van this explicitly when I interviewed him for ACM Queue in late October and the answer is that there's an rendezvous point embedded in the name. Interview should pop out on-line early next year and you can see if you agree with my interpretation of what he said. Re: location -- "location" in my notes means well defined place in the network -- has nothing to do with physical geography (who cares where on earth a networked place is?). Thanks! Craig In message <49341D2F.50804 at reed.com>, "David P. Reed" writes: >I've studied Van's and there is no "location" embedded in his system. >Unless of course you redefine the word location to mean something quite >different than "geographic place". > >Craig Partridge wrote: >> Hi Dave: >> >> So fine, call it datum or message -- the point is that some things that >> are desired have a single current instance. That instance may get replicate >d >> eventually, or not, depending on context. It may be that you can >> retrieve something similar from other, more widely available, >> sources/instances/etc. >> >> But you haven't responded to the point I made which is that when you >> want something that is rare, what I've discovered is all systems to >> date embed location. If I'm understanding your note, you think I'm >> saying there's a reference copy/instance that we all must go back to >> ala the Grail (nope, that's not what I'm saying) or that I'm otherwise >> intentionally making things rare. Instead I'm saying, when something is >> rare (1 instance/instantiation/whatever in the world -- and, by the way, >> I care about such cases as I used to be a medievalist and occasionally >> was probably the first person to see a document since it was written 700 >> years ago), I've found that every information retrieval system (including >> Van's) embeds a location. >> >> Thanks! >> >> Craig >> >> In message <49340902.2050400 at reed.com>, "David P. Reed" writes: >> >> >>> Interesting. >>> >>> Your presumption that information is a matter of copies, and that "sole >>> copy" is a well-defined term, suggests a fundamental difference in our >>> understanding of the word "information". >>> >>> Had you used the word "datum" or "message" (two human constructed >>> concepts), I might agree. But "information" is not a synonym for either >>> term. Both are *representations* or *instantiations* of information. >>> >>> A piece of paper with a number printed on it may be the "sole instance" >>> of a printed piece of paper with that particular representation of >>> information. But if that number represents (say) "the total net value >>> of my bank account on Dec. 1 2008", it is not at all the only "copy" of >>> information. >>> >>> Information typically exists independent of form or representation. It >>> is a constructed, calculated, computed thing. It doesn't exist >>> independently, nor does it exist in sole form. >>> >>> Yes, I could agree with you that if information were forced to exist in >>> "single copy" form, it would require some complex and amazing procedure >>> to copy that piece of information into another place. But, once copied, >>> it would be smeared across half the universe. (or alternatively you >>> could decide, since "place" is really not a very easy-to-define term, >>> that the information is still in one place, but the universe has now >>> collapsed significantly, because all the places "containing" (whatever >>> that means) the information would be "the same place"). >>> >>> But independent of that: why is any information system designed to have >>> data in a "sole copy"? Van asks this question, and he is wise to ask >>> this question. Most computer systems work by having vast numbers of >>> copies of data. We constantly see most information representations used >>> in computation in the form of cached data. >>> >>> It seems to me that it is a pure fetish, perhaps conditioned by >>> training, to posit that most information is represented by single >>> copies. That way lies "brittle" failure-prone engineering. >>> >>> Let a thousand representations bloom. Many of them will be copies of a >>> datum. Others will be computable recovery algorithms - some of which >>> invent an abstraction called "location". But even that abstraction >>> called location is not a "place" in the sense of a 4 dimensional spatial >>> metric based coordinate system. I address a piece of paper by its >>> title, not its current location in the file folder on someone's desk. >>> >>> >>> Craig Partridge wrote: >>> >>>>> Our dear friend, Van Jacobsen, has decided that layering "where" under >>>>> "what" with regard to data is neither necessary, nor a good idea. >>>>> >>>>> I agree: confusing the container with the information it happens to hold >>>>> is a layer violation. Information is not bound to place, nor is there a >>>>> primary instance. Information is place-free, and perhaps the idea that >>>>> there must be a "place" where it "is" is an idea whose time should pass, >>>>> and the purveyors of that idea as a holy writ (the OSI layering) retired >>>>> to play golf. >>>>> >>>>> >>>> Hi Dave: >>>> >>>> Much as I'd like to believe this particular theory (as it is nice, clean >>>> and pretty), practical considerations suggest we're not there. >>>> >>>> I've talked with some of the folks working on information and seeking >>>> to make information place-free, and the answer, so far, that I've gotten >>>> is that you get part-way there. If the information is popular or >>>> "nearby" then there are mechanisms that can be viewed as place-free (and >>>> a good thing -- it means that the more popular a piece of information is, >>>> the easier to get easily and perhaps from somewhere locally). >>>> >>>> But if you ask about retrieving an uncommon piece of information then >>>> you discover "location" crawls out from under the covers. That is, >>>> if you ask the question "where do I find the sole copy of item X", you >>>> learn that somewhere hidden in the name of X is a location -- perhaps >>>> of X or perhaps of a rendezvous server that knows where X is -- but >>>> there's the location of something buried in there. >>>> >>>> Thanks! >>>> >>>> Craig >>>> >>>> >>>> >> >> From dpreed at reed.com Mon Dec 1 09:48:23 2008 From: dpreed at reed.com (David P. Reed) Date: Mon, 01 Dec 2008 12:48:23 -0500 Subject: [e2e] a means to an end In-Reply-To: <20081201173207.DE7A828E155@aland.bbn.com> References: <20081201173207.DE7A828E155@aland.bbn.com> Message-ID: <49342367.7070503@reed.com> It may be that I just can't see the "rendezvous place" in Van's work. Nonetheless, I will claim it isn't essential. Can you define "well defined place in the network", please? (in particular, the words "defined" and "place" need definition here.) "Nothing to do with physical geography" is an interesting constraint on your definition. I would claim that the word "place" in your definition is nothing more than a synonym for "function that is effectively computable by a realized physical computational device". In other words, a computed mapping from "the state of the entire system" to an element of an abstract set of values. For example, an algorithmically computed mapping from the state of the entire system to a member of a set of items that have 2^32 possible states. The algorithm here might involve many things, but is very rarely focused on what we consider physical location. As you admit when you say "nothing to do with physical geography". So define "well defined place in the network" as YOU define it. Craig Partridge wrote: > Hi Dave: > > I asked Van this explicitly when I interviewed him for ACM Queue in late > October and the answer is that there's an rendezvous point embedded in the > name. Interview should pop out on-line early next year and you can see if > you agree with my interpretation of what he said. > > Re: location -- "location" in my notes means well defined place in the > network -- has nothing to do with physical geography (who cares where > on earth a networked place is?). > > Thanks! > > Craig > > In message <49341D2F.50804 at reed.com>, "David P. Reed" writes: > > >> I've studied Van's and there is no "location" embedded in his system. >> Unless of course you redefine the word location to mean something quite >> different than "geographic place". >> >> Craig Partridge wrote: >> >>> Hi Dave: >>> >>> So fine, call it datum or message -- the point is that some things that >>> are desired have a single current instance. That instance may get replicate >>> > >d > >>> eventually, or not, depending on context. It may be that you can >>> retrieve something similar from other, more widely available, >>> sources/instances/etc. >>> >>> But you haven't responded to the point I made which is that when you >>> want something that is rare, what I've discovered is all systems to >>> date embed location. If I'm understanding your note, you think I'm >>> saying there's a reference copy/instance that we all must go back to >>> ala the Grail (nope, that's not what I'm saying) or that I'm otherwise >>> intentionally making things rare. Instead I'm saying, when something is >>> rare (1 instance/instantiation/whatever in the world -- and, by the way, >>> I care about such cases as I used to be a medievalist and occasionally >>> was probably the first person to see a document since it was written 700 >>> years ago), I've found that every information retrieval system (including >>> Van's) embeds a location. >>> >>> Thanks! >>> >>> Craig >>> >>> In message <49340902.2050400 at reed.com>, "David P. Reed" writes: >>> >>> >>> >>>> Interesting. >>>> >>>> Your presumption that information is a matter of copies, and that "sole >>>> copy" is a well-defined term, suggests a fundamental difference in our >>>> understanding of the word "information". >>>> >>>> Had you used the word "datum" or "message" (two human constructed >>>> concepts), I might agree. But "information" is not a synonym for either >>>> term. Both are *representations* or *instantiations* of information. >>>> >>>> A piece of paper with a number printed on it may be the "sole instance" >>>> of a printed piece of paper with that particular representation of >>>> information. But if that number represents (say) "the total net value >>>> of my bank account on Dec. 1 2008", it is not at all the only "copy" of >>>> information. >>>> >>>> Information typically exists independent of form or representation. It >>>> is a constructed, calculated, computed thing. It doesn't exist >>>> independently, nor does it exist in sole form. >>>> >>>> Yes, I could agree with you that if information were forced to exist in >>>> "single copy" form, it would require some complex and amazing procedure >>>> to copy that piece of information into another place. But, once copied, >>>> it would be smeared across half the universe. (or alternatively you >>>> could decide, since "place" is really not a very easy-to-define term, >>>> that the information is still in one place, but the universe has now >>>> collapsed significantly, because all the places "containing" (whatever >>>> that means) the information would be "the same place"). >>>> >>>> But independent of that: why is any information system designed to have >>>> data in a "sole copy"? Van asks this question, and he is wise to ask >>>> this question. Most computer systems work by having vast numbers of >>>> copies of data. We constantly see most information representations used >>>> in computation in the form of cached data. >>>> >>>> It seems to me that it is a pure fetish, perhaps conditioned by >>>> training, to posit that most information is represented by single >>>> copies. That way lies "brittle" failure-prone engineering. >>>> >>>> Let a thousand representations bloom. Many of them will be copies of a >>>> datum. Others will be computable recovery algorithms - some of which >>>> invent an abstraction called "location". But even that abstraction >>>> called location is not a "place" in the sense of a 4 dimensional spatial >>>> metric based coordinate system. I address a piece of paper by its >>>> title, not its current location in the file folder on someone's desk. >>>> >>>> >>>> Craig Partridge wrote: >>>> >>>> >>>>>> Our dear friend, Van Jacobsen, has decided that layering "where" under >>>>>> "what" with regard to data is neither necessary, nor a good idea. >>>>>> >>>>>> I agree: confusing the container with the information it happens to hold >>>>>> is a layer violation. Information is not bound to place, nor is there a >>>>>> primary instance. Information is place-free, and perhaps the idea that >>>>>> there must be a "place" where it "is" is an idea whose time should pass, >>>>>> and the purveyors of that idea as a holy writ (the OSI layering) retired >>>>>> to play golf. >>>>>> >>>>>> >>>>>> >>>>> Hi Dave: >>>>> >>>>> Much as I'd like to believe this particular theory (as it is nice, clean >>>>> and pretty), practical considerations suggest we're not there. >>>>> >>>>> I've talked with some of the folks working on information and seeking >>>>> to make information place-free, and the answer, so far, that I've gotten >>>>> is that you get part-way there. If the information is popular or >>>>> "nearby" then there are mechanisms that can be viewed as place-free (and >>>>> a good thing -- it means that the more popular a piece of information is, >>>>> the easier to get easily and perhaps from somewhere locally). >>>>> >>>>> But if you ask about retrieving an uncommon piece of information then >>>>> you discover "location" crawls out from under the covers. That is, >>>>> if you ask the question "where do I find the sole copy of item X", you >>>>> learn that somewhere hidden in the name of X is a location -- perhaps >>>>> of X or perhaps of a rendezvous server that knows where X is -- but >>>>> there's the location of something buried in there. >>>>> >>>>> Thanks! >>>>> >>>>> Craig >>>>> >>>>> >>>>> >>>>> >>> >>> > > From craig at aland.bbn.com Mon Dec 1 10:08:20 2008 From: craig at aland.bbn.com (Craig Partridge) Date: Mon, 01 Dec 2008 13:08:20 -0500 Subject: [e2e] a means to an end In-Reply-To: Your message of "Mon, 01 Dec 2008 12:48:23 EST." <49342367.7070503@reed.com> Message-ID: <20081201180820.C89C828E155@aland.bbn.com> In message <49342367.7070503 at reed.com>, "David P. Reed" writes: >So define "well defined place in the network" as YOU define it. A stable object name that can reliably be translated to an address in a communications graph. Explaining a bit (since we seem to have an impedance mismatch): * stable object name -- it is a name that has longevity -- it isn't a temporary name created for 5 minutes on-line. * reliably translated to an address -- the address of the object can change but the object always exists -- you can address it (I'm being careful here to permit intermittent connectivity ala DTN -- what I'm saying is you can address the object and send it a request, that doesn't mean you can communicate with it in real-time). * communications graph -- I'd like a better term (as graphs model nodes and edges, which for wireless isn't the abstraction I want) but the point is that the combination of RF/wires/fiber/nodes that make up our communications networks are reasonably independent of geography. (I can have a subnet spanning continents.) Note there's some clumsiness here -- I originally used "node" and then chose "object". Neither word is quite right. I hope the broad point is clear. Thanks! Craig From dpreed at reed.com Mon Dec 1 10:23:07 2008 From: dpreed at reed.com (David P. Reed) Date: Mon, 01 Dec 2008 13:23:07 -0500 Subject: [e2e] a means to an end In-Reply-To: <20081201180820.C89C828E155@aland.bbn.com> References: <20081201180820.C89C828E155@aland.bbn.com> Message-ID: <49342B8B.9000801@reed.com> some points about the non-generality of your definition, which is tied to a very specific systems architecture. The need for such a "tie" has always been my main point. I guess wireless communications systems are not part of your model. Many such systems don't have a "communications graph". (if you stand on your head you can try to construct one if it is needed for some discussion that cannot take place without one in hand, but Maxwell's equations don't construct such a graph). I don't know what an object name is: content addressable memories hold information, but don't necessarily have "object names", nor is an "object name" the primary retrieval means. Why "reliably translated"? Xerox PUP used addresses that could be mistranslated (48 bit UIDs), but the PUP protocol system worked reliably, having been constructed in a manner that followed von Neumann's constructive proof that you could build reliable systems out of unreliable parts. Just as there is no need for "reliability" at the base of the network, there is no need for "location" at the base. Craig Partridge wrote: > In message <49342367.7070503 at reed.com>, "David P. Reed" writes: > > >> So define "well defined place in the network" as YOU define it. >> > > A stable object name that can reliably be translated to an address in a > communications graph. > > Explaining a bit (since we seem to have an impedance mismatch): > > * stable object name -- it is a name that has longevity -- it isn't > a temporary name created for 5 minutes on-line. > > * reliably translated to an address -- the address of the object > can change but the object always exists -- you can address it (I'm being > careful here to permit intermittent connectivity ala DTN -- > what I'm saying is you can address the object and send it a request, > that doesn't mean you can communicate with it in real-time). > > * communications graph -- I'd like a better term (as graphs > model nodes and edges, which for wireless isn't the abstraction > I want) but the point is that the combination of RF/wires/fiber/nodes > that make up our communications networks are reasonably independent > of geography. (I can have a subnet spanning continents.) > > Note there's some clumsiness here -- I originally used "node" and then > chose "object". Neither word is quite right. I hope the broad point is > clear. > > Thanks! > > Craig > > From craig at aland.bbn.com Mon Dec 1 10:27:57 2008 From: craig at aland.bbn.com (Craig Partridge) Date: Mon, 01 Dec 2008 13:27:57 -0500 Subject: [e2e] a means to an end In-Reply-To: Your message of "Mon, 01 Dec 2008 13:23:07 EST." <49342B8B.9000801@reed.com> Message-ID: <20081201182757.DAF8628E155@aland.bbn.com> Hi Dave: Did you read my note? * Your point about wireless was made in my note. * Reliably translated didn't mean the address was right. PUP works just fine in my definition. What I meant was that the translation function was present and gave a useful result (rather than, say, "no address"). I have the sense we're talking past each other (and to give other email boxes a rest, I'll quit here). Craig In message <49342B8B.9000801 at reed.com>, "David P. Reed" writes: >some points about the non-generality of your definition, which is tied >to a very specific systems architecture. The need for such a "tie" has >always been my main point. > >I guess wireless communications systems are not part of your model. >Many such systems don't have a "communications graph". (if you stand on >your head you can try to construct one if it is needed for some >discussion that cannot take place without one in hand, but Maxwell's >equations don't construct such a graph). > >I don't know what an object name is: content addressable memories hold >information, but don't necessarily have "object names", nor is an >"object name" the primary retrieval means. > >Why "reliably translated"? Xerox PUP used addresses that could be >mistranslated (48 bit UIDs), but the PUP protocol system worked >reliably, having been constructed in a manner that followed von >Neumann's constructive proof that you could build reliable systems out >of unreliable parts. > >Just as there is no need for "reliability" at the base of the network, >there is no need for "location" at the base. > >Craig Partridge wrote: >> In message <49342367.7070503 at reed.com>, "David P. Reed" writes: >> >> >>> So define "well defined place in the network" as YOU define it. >>> >> >> A stable object name that can reliably be translated to an address in a >> communications graph. >> >> Explaining a bit (since we seem to have an impedance mismatch): >> >> * stable object name -- it is a name that has longevity -- it isn't >> a temporary name created for 5 minutes on-line. >> >> * reliably translated to an address -- the address of the object >> can change but the object always exists -- you can address it (I'm bei >ng >> careful here to permit intermittent connectivity ala DTN -- >> what I'm saying is you can address the object and send it a request, >> that doesn't mean you can communicate with it in real-time). >> >> * communications graph -- I'd like a better term (as graphs >> model nodes and edges, which for wireless isn't the abstraction >> I want) but the point is that the combination of RF/wires/fiber/nodes >> that make up our communications networks are reasonably independent >> of geography. (I can have a subnet spanning continents.) >> >> Note there's some clumsiness here -- I originally used "node" and then >> chose "object". Neither word is quite right. I hope the broad point is >> clear. >> >> Thanks! >> >> Craig >> >> From dpreed at reed.com Mon Dec 1 10:44:35 2008 From: dpreed at reed.com (David P. Reed) Date: Mon, 01 Dec 2008 13:44:35 -0500 Subject: [e2e] a means to an end In-Reply-To: <20081201182757.DAF8628E155@aland.bbn.com> References: <20081201182757.DAF8628E155@aland.bbn.com> Message-ID: <49343093.3010504@reed.com> Craig - I did read your note - I was referring to more general wireless designs: I think you were focused on packet radios, e.g. systems that try to simulate wire-like behaviors (rather than, for example, systems that work by what some call "analog network coding", for example). Happy to give others a rest. I found the debate stimulating, and I've learned a lot, I think, about what you meant by "location". Thanks. Craig Partridge wrote: > Hi Dave: > > Did you read my note? > > * Your point about wireless was made in my note. > > * Reliably translated didn't mean the address was right. PUP works just > fine in my definition. What I meant was that the translation function > was present and gave a useful result (rather than, say, "no address"). > > I have the sense we're talking past each other (and to give other email > boxes a rest, I'll quit here). > > Craig > > > In message <49342B8B.9000801 at reed.com>, "David P. Reed" writes: > > >> some points about the non-generality of your definition, which is tied >> to a very specific systems architecture. The need for such a "tie" has >> always been my main point. >> >> I guess wireless communications systems are not part of your model. >> Many such systems don't have a "communications graph". (if you stand on >> your head you can try to construct one if it is needed for some >> discussion that cannot take place without one in hand, but Maxwell's >> equations don't construct such a graph). >> >> I don't know what an object name is: content addressable memories hold >> information, but don't necessarily have "object names", nor is an >> "object name" the primary retrieval means. >> >> Why "reliably translated"? Xerox PUP used addresses that could be >> mistranslated (48 bit UIDs), but the PUP protocol system worked >> reliably, having been constructed in a manner that followed von >> Neumann's constructive proof that you could build reliable systems out >> of unreliable parts. >> >> Just as there is no need for "reliability" at the base of the network, >> there is no need for "location" at the base. >> >> Craig Partridge wrote: >> >>> In message <49342367.7070503 at reed.com>, "David P. Reed" writes: >>> >>> >>> >>>> So define "well defined place in the network" as YOU define it. >>>> >>>> >>> A stable object name that can reliably be translated to an address in a >>> communications graph. >>> >>> Explaining a bit (since we seem to have an impedance mismatch): >>> >>> * stable object name -- it is a name that has longevity -- it isn't >>> a temporary name created for 5 minutes on-line. >>> >>> * reliably translated to an address -- the address of the object >>> can change but the object always exists -- you can address it (I'm bei >>> > >ng > >>> careful here to permit intermittent connectivity ala DTN -- >>> what I'm saying is you can address the object and send it a request, >>> that doesn't mean you can communicate with it in real-time). >>> >>> * communications graph -- I'd like a better term (as graphs >>> model nodes and edges, which for wireless isn't the abstraction >>> I want) but the point is that the combination of RF/wires/fiber/nodes >>> that make up our communications networks are reasonably independent >>> of geography. (I can have a subnet spanning continents.) >>> >>> Note there's some clumsiness here -- I originally used "node" and then >>> chose "object". Neither word is quite right. I hope the broad point is >>> clear. >>> >>> Thanks! >>> >>> Craig >>> >>> >>> > > From L.Wood at surrey.ac.uk Mon Dec 1 15:39:44 2008 From: L.Wood at surrey.ac.uk (L.Wood@surrey.ac.uk) Date: Mon, 1 Dec 2008 23:39:44 -0000 Subject: [e2e] a means to an end References: <20081201180820.C89C828E155@aland.bbn.com> <49342B8B.9000801@reed.com> Message-ID: <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D@EVS-EC1-NODE4.surrey.ac.uk> David, Interesting that he thrust of current IRTF delay-tolerant networking work has effectively turned your statement below on its head, in believing that there is no need for reliability at the top of the network, and no need for location at the top of the network, either. How the network base assures sufficient reliability and assures that endpoint identifiers map to something meaningful would seem to be open problems... L. > Just as there is no need for "reliability" at the base of the network, > there is no need for "location" at the base. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.postel.org/pipermail/end2end-interest/attachments/20081201/b4962e7c/attachment.html From dpreed at reed.com Mon Dec 1 16:22:41 2008 From: dpreed at reed.com (David P. Reed) Date: Mon, 01 Dec 2008 19:22:41 -0500 Subject: [e2e] a means to an end In-Reply-To: <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D@EVS-EC1-NODE4.surrey.ac.uk> References: <20081201180820.C89C828E155@aland.bbn.com> <49342B8B.9000801@reed.com> <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D@EVS-EC1-NODE4.surrey.ac.uk> Message-ID: <49347FD1.6040602@reed.com> Two thoughts: Any layering builds from something ... so it's interesting what you posit as the base case from which the mathematical induction follows. There is an alternative to layering: constructing a system that recurses or contains a looped-back-upon-itself dependency, in which case, the resulting behavior can be characterized by the least-fixed-point (LFP, result of the Y combinator, or some other formulation) of the functional recursion. I realize these are abstract mathematical concepts, not always taught to the kids these days. HTML and Python are thought to be verging on too difficult. Regarding the IRTF DTN stuff: is the system layered or based on a least fixed point? L.Wood at surrey.ac.uk wrote: > > David, > > Interesting that he thrust of current IRTF delay-tolerant > networking work has effectively turned your statement below > on its head, in believing that there is no need for reliability > at the top of the network, and no need for location at the top > of the network, either. > > How the network base assures sufficient reliability and assures > that endpoint identifiers map to something meaningful would seem > to be open problems... > > L. > > > > > Just as there is no need for "reliability" at the base of the network, > > there is no need for "location" at the base. > From Jon.Crowcroft at cl.cam.ac.uk Tue Dec 2 00:24:03 2008 From: Jon.Crowcroft at cl.cam.ac.uk (Jon Crowcroft) Date: Tue, 02 Dec 2008 08:24:03 +0000 Subject: [e2e] a means to an end In-Reply-To: <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D@EVS-EC1-NODE4.surrey.ac.uk> References: <20081201180820.C89C828E155@aland.bbn.com> <49342B8B.9000801@reed.com> <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D@EVS-EC1-NODE4.surrey.ac.uk> Message-ID: as well as DTN folks combatting layering and assumptions (which we took on board in haggle, for example, and adopted - viz www.cl.cam.ac.uk/~ph315/publications/haggle-ubicomp2007.pdf (as have others) and van et al combatting point-to-pointless networking, there are quite a few other people reaching out along these directions - i blogged some of the pieces as part of a course in comms i teach to undergrads in cambridge notably psirp... http://clogspotclog.blogspot.com/2008/12/dcii-11208.html i think the conversation recently has confused (or conflated) several different pieces of architecture 1. protocol system composition 2. data driven networking paradigms 3. information coding and representation I certainly would be kean in the very long term to conflate these, especially in multi"hop" wireless nets where the efficiency gains are big, but I am not so sure about mixing them up on the next stage of the internet, principally because of ownership and privacy. (yes, i realize that there are extreme ways one can provie even more privacy as well as censorship proof networking by doing clever co-coding of oobjects during transmission and caching (or however you want to view it in a DONA world...) - i just dont think certain agencies will let us build the whole net that way btw, there's a cool description of such a net in Neal Stepheson's Diamond Age (as well as an aweseome envisaging of Kay's "A personal computer for children of all ages" http://www.mprove.de/diplom/gui/Kay72a.pdf which we could well read - it probably invalidates most of the mobile handset industry's patents:) In missive <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D at EVS-EC1-NODE4.surrey.ac.uk>, L.Wood at surrey.ac.uk typed: >>This is a multi-part message in MIME format. >> >>------_=_NextPart_001_01C9540E.AB036396 >>Content-Type: text/plain; >> charset="iso-8859-1" >>Content-Transfer-Encoding: quoted-printable >> >>David, >> >>Interesting that he thrust of current IRTF delay-tolerant >>networking work has effectively turned your statement below >>on its head, in believing that there is no need for reliability >>at the top of the network, and no need for location at the top >>of the network, either. >> >>How the network base assures sufficient reliability and assures >>that endpoint identifiers map to something meaningful would seem >>to be open problems...=20 >> >>L. >> >> >> >>> Just as there is no need for "reliability" at the base of the network, = >> >>> there is no need for "location" at the base. >> >>------_=_NextPart_001_01C9540E.AB036396 >>Content-Type: text/html; >> charset="iso-8859-1" >>Content-Transfer-Encoding: quoted-printable >> >> >> >> >>>charset=3Diso-8859-1"> >>>6.5.7653.38"> >>RE: [e2e] a means to an end >> >> >> >> >>

David,
>>
>>Interesting that he thrust of current IRTF delay-tolerant
>>networking work has effectively turned your statement below
>>on its head, in believing that there is no need for reliability
>>at the top of the network, and no need for location at the top
>>of the network, either.
>>
>>How the network base assures sufficient reliability and assures
>>that endpoint identifiers map to something meaningful would seem
>>to be open problems...
>>
>>L.
>>
>><>HREF=3D"http://www.ee.surrey.ac.uk/Personal/L.Wood/">http://www.ee.surrey= >>.ac.uk/Personal/L.Wood/><L.Wood at surrey.ac.uk>
>>
>>> Just as there is no need for "reliability" at the base of = >>the network,
>>> there is no need for "location" at the base.
>> >>

>> >> >> >>------_=_NextPart_001_01C9540E.AB036396-- cheers jon From L.Wood at surrey.ac.uk Tue Dec 2 03:34:56 2008 From: L.Wood at surrey.ac.uk (Lloyd Wood) Date: Tue, 2 Dec 2008 11:34:56 +0000 Subject: [e2e] a means to an end In-Reply-To: <49347FD1.6040602@reed.com> References: <20081201180820.C89C828E155@aland.bbn.com> <49342B8B.9000801@reed.com> <4835AFD53A246A40A3B8DA85D658C4BE7B0D7D@EVS-EC1-NODE4.surrey.ac.uk> <49347FD1.6040602@reed.com> Message-ID: <382FAE85-DBD0-4AD1-8F01-9AF8F3F45F6A@surrey.ac.uk> The DTNRG bundle architecture has some recursion in it - nesting of bundle security blocks to give security in the network, and the concept of security gateways which effectively do tunnelling by nesting these blocks. These have had to be reused for reliability and to enable better performance from the network (allowing nodes check outer reliability blocks for early resends of corrupted bundles). The behaviour sans any of these is no reliability or self-checking (of headers, even)/no security/slow network performance as the minimum. But there's also layering - the assumption that bundling sits on top of a network-specific "convergence layer" to traverse each local subnet (but is somehow unaffected by the properties of said convergence layers. The desired properties of the convergence layers are unspecified.) On induction: what the base case is, and where in layers, is interesting. Other than 'you can't start in the middle,' it's hard to say anything concrete about it, given that the computing principle of 'anything can be achieved with a level of indirection' counters logical induction and following clear properties or behaviour up or down the stack. The end-to-end principle says the induction of layers of an unreliable network stack leading to unreliability can be countered at the topmost layer where reliability is assured e2e as a level of indirection. Performance is a system behaviour, though, and visible as an effect of the behaviour of all layers. Naming is usually handled as indirection at every layer; looking at it through induction doesn't shed any light. John Day's _Patterns in Network Architecture_ is big on recursion. I suppose one could argue that, with layering and indirection, you can fool most of the others most of the time; when relying on indirection in a recursive setup, you're only fooling yourself -- so the recursive architecture has to be better-thought-out. On 2 Dec 2008, at 00:22, David P. Reed wrote: > Two thoughts: > > Any layering builds from something ... so it's interesting what > you posit as the base case from which the mathematical induction > follows. > > There is an alternative to layering: constructing a system that > recurses or contains a looped-back-upon-itself dependency, in which > case, the resulting behavior can be characterized by the least-fixed- > point (LFP, result of the Y combinator, or some other formulation) > of the functional recursion. > > I realize these are abstract mathematical concepts, not always > taught to the kids these days. HTML and Python are thought to be > verging on too difficult. > > Regarding the IRTF DTN stuff: is the system layered or based on a > least fixed point? > > > L.Wood at surrey.ac.uk wrote: >> >> David, >> >> Interesting that he thrust of current IRTF delay-tolerant >> networking work has effectively turned your statement below >> on its head, in believing that there is no need for reliability >> at the top of the network, and no need for location at the top >> of the network, either. >> >> How the network base assures sufficient reliability and assures >> that endpoint identifiers map to something meaningful would seem >> to be open problems... >> >> L. >> >> >> >> > Just as there is no need for "reliability" at the base of the >> network, >> > there is no need for "location" at the base. >> DTN work: http://info.ee.surrey.ac.uk/Personal/L.Wood/saratoga/ From dpreed at reed.com Tue Dec 2 10:08:35 2008 From: dpreed at reed.com (David P. Reed) Date: Tue, 02 Dec 2008 13:08:35 -0500 Subject: [e2e] a means to an end In-Reply-To: <88634386-C2A3-46D3-8B3B-1B728A9AD0BE@cs.cmu.edu> References: <20081201165329.6954028E161@aland.bbn.com> <88634386-C2A3-46D3-8B3B-1B728A9AD0BE@cs.cmu.edu> Message-ID: <493579A3.6030707@reed.com> Objects != information. No need to objectify information anymore than need to objectify women. :-) Regarding flooding - the alternatives not so black and white as you make them out to be. Search can scale rather dramatically, under the same conditions that routing can scale: when things don't move. The difference is that search doesn't require that the pre-condition of static placement be satisfied... a good search strategy adapts its work effort to conditions. Instead of flood first, one could do depth-based search from a landmark near the last appearance known, if given a network that is relatively static, where things move slowly. Algorithms are great things. They can be designed to adapt, while still doing well in simple cases. So "flooding" seems just a straw man argument made by those who don't want to consider adaptive algorithms. David Andersen wrote: > Interesting discussion. I sense something fundamental here in the > needles vs. haystack side of things: one can find hay easily without > needing to embed location at all, b/c you can flood to find it and > expect to find it soon. For scalability, though, needles need some > well-defined rendezvous point. > > That rendezvous point eventually needs to map to a physical > realization that stores, at minimum, a mapping that tells you where to > get the data you're interested in. Or could store the data itself. > > This is, of course, assuming that the # of data objects in the > universe is substantially larger than the # of globally, independently > routable objects in the universe. Which is probably a reasonable > assumption for the medium term. > > -Dave > > On Dec 1, 2008, at 11:53 AM, Craig Partridge wrote: > >> >> Hi Dave: >> >> So fine, call it datum or message -- the point is that some things that >> are desired have a single current instance. That instance may get >> replicated >> eventually, or not, depending on context. It may be that you can >> retrieve something similar from other, more widely available, >> sources/instances/etc. >> >> But you haven't responded to the point I made which is that when you >> want something that is rare, what I've discovered is all systems to >> date embed location. If I'm understanding your note, you think I'm >> saying there's a reference copy/instance that we all must go back to >> ala the Grail (nope, that's not what I'm saying) or that I'm otherwise >> intentionally making things rare. Instead I'm saying, when something is >> rare (1 instance/instantiation/whatever in the world -- and, by the way, >> I care about such cases as I used to be a medievalist and occasionally >> was probably the first person to see a document since it was written 700 >> years ago), I've found that every information retrieval system >> (including >> Van's) embeds a location. >> >> Thanks! >> >> Craig >> >> In message <49340902.2050400 at reed.com>, "David P. Reed" writes: >> >>> Interesting. >>> >>> Your presumption that information is a matter of copies, and that "sole >>> copy" is a well-defined term, suggests a fundamental difference in our >>> understanding of the word "information". >>> >>> Had you used the word "datum" or "message" (two human constructed >>> concepts), I might agree. But "information" is not a synonym for >>> either >>> term. Both are *representations* or *instantiations* of information. >>> >>> A piece of paper with a number printed on it may be the "sole instance" >>> of a printed piece of paper with that particular representation of >>> information. But if that number represents (say) "the total net value >>> of my bank account on Dec. 1 2008", it is not at all the only "copy" of >>> information. >>> >>> Information typically exists independent of form or >>> representation. It >>> is a constructed, calculated, computed thing. It doesn't exist >>> independently, nor does it exist in sole form. >>> >>> Yes, I could agree with you that if information were forced to exist in >>> "single copy" form, it would require some complex and amazing procedure >>> to copy that piece of information into another place. But, once >>> copied, >>> it would be smeared across half the universe. (or alternatively you >>> could decide, since "place" is really not a very easy-to-define term, >>> that the information is still in one place, but the universe has now >>> collapsed significantly, because all the places "containing" (whatever >>> that means) the information would be "the same place"). >>> >>> But independent of that: why is any information system designed to have >>> data in a "sole copy"? Van asks this question, and he is wise to ask >>> this question. Most computer systems work by having vast numbers of >>> copies of data. We constantly see most information representations used >>> in computation in the form of cached data. >>> >>> It seems to me that it is a pure fetish, perhaps conditioned by >>> training, to posit that most information is represented by single >>> copies. That way lies "brittle" failure-prone engineering. >>> >>> Let a thousand representations bloom. Many of them will be copies of a >>> datum. Others will be computable recovery algorithms - some of which >>> invent an abstraction called "location". But even that abstraction >>> called location is not a "place" in the sense of a 4 dimensional >>> spatial >>> metric based coordinate system. I address a piece of paper by its >>> title, not its current location in the file folder on someone's desk. >>> >>> >>> Craig Partridge wrote: >>>>> Our dear friend, Van Jacobsen, has decided that layering "where" >>>>> under >>>>> "what" with regard to data is neither necessary, nor a good idea. >>>>> >>>>> I agree: confusing the container with the information it happens >>>>> to hold >>>>> is a layer violation. Information is not bound to place, nor is >>>>> there a >>>>> primary instance. Information is place-free, and perhaps the idea >>>>> that >>>>> there must be a "place" where it "is" is an idea whose time should >>>>> pass, >>>>> and the purveyors of that idea as a holy writ (the OSI layering) >>>>> retired >>>>> to play golf. >>>>> >>>> >>>> Hi Dave: >>>> >>>> Much as I'd like to believe this particular theory (as it is nice, >>>> clean >>>> and pretty), practical considerations suggest we're not there. >>>> >>>> I've talked with some of the folks working on information and seeking >>>> to make information place-free, and the answer, so far, that I've >>>> gotten >>>> is that you get part-way there. If the information is popular or >>>> "nearby" then there are mechanisms that can be viewed as place-free >>>> (and >>>> a good thing -- it means that the more popular a piece of >>>> information is, >>>> the easier to get easily and perhaps from somewhere locally). >>>> >>>> But if you ask about retrieving an uncommon piece of information then >>>> you discover "location" crawls out from under the covers. That is, >>>> if you ask the question "where do I find the sole copy of item X", you >>>> learn that somewhere hidden in the name of X is a location -- perhaps >>>> of X or perhaps of a rendezvous server that knows where X is -- but >>>> there's the location of something buried in there. >>>> >>>> Thanks! >>>> >>>> Craig >>>> >>>> >> >