[e2e] a means to an end
David P. Reed
dpreed at reed.com
Thu Nov 6 13:48:19 PST 2008
It can be in many places, including everywhere and nowhere. As an
example of the latter, consider the location of the piece of information
called the "majority" of a set of voters. Let's assume that the set of
voters has cardinality N. (Both Dave Gifford and I, and later Leslie
Lamport, built practical networked computing systems that were based on
key information elements being stored as majorities of this sort).
The "location" of such a majority is, in some sense, a superposition of
subsets that have the following property: the subset has floor(N/2)+1
elements who vote in the same way. Depending on the preponerance of
agreeable voters, the "location" of the majority has at least
2^(floor(N/2)) possible states, all of which are "a location of the
I'm bloody serious. The idea that one must access information by
*first* deciding *where* to look and then asking a container is JUST
WRONG. Or to be more polite, it is a design choice that we made
arbitrarily in the Internet. But it is not unambiguously "right".
Craig Partridge wrote:
> Hi Dave:
> Interesting you invoked Van as it was a talk with Van last week that led to
> my comment. I suspect this means you mean one thing by your comment and
> I mean something else (i.e. we're in agreement but having a semantics
> So let me try restating what I took from chatting with Van (with the
> understanding that this is my take, not necessarily Van's).
> * Information is place free.
> * Actually accessing that information, in the worst case, requires
> a rendezvous point (if it is popular data, it doesn't -- someone
> near you will have a copy -- but information that is of only occasional
> interest requires more effort).
> * To get to the rendezvous point, you need some way to convert from the
> name/label/ID of the information to a location of a rendezvous
> point that knows where the information currently resides (or, better,
> can get the information sent to you).
> In message <49135FAA.6080603 at reed.com>, "David P. Reed" writes:
>> 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.
>> Craig Partridge wrote:
>>> In message <49134E2F.8010704 at reed.com>, "David P. Reed" writes:
>>>> Why should "location" be relevant to networking? Must all wires be
>>>> buried permanently in the ground? Does wireless and mobility not occur?
>>> I think it is easier to see the merit of location when one thinks about
>>> retrieving data. You need some clue as to where the data is.
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