[e2e] a means to an end
craig at aland.bbn.com
Mon Dec 1 10:27:57 PST 2008
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).
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
>> 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
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