On Mon, 2009-06-08 at 14:22 +0900, Masataka Ohta wrote:
As you say "IN NETWORKING", I'm afraid you haven't read his original
paper "END-TO-END ARGUMENTS IN SYSTEM DESIGN", which is on "system
design" in general and not necessarily "in networking". For example,
in the original paper, RISC (Reduced Instruction Set Computer) is
given as an example of end to end design.
Er, no. The article states:
"The arguments that are used in support of reduced instruction set
computer (RISC) architecture are similar to end-to-end arguments."
I.e. the arguments for end to end are similar to the arguments for RISC.
This is not the same as saying that RISC is an example of end to end
design.
Both of the papers are freely downloadable.
The original paper:
http://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.pdf
The paper in 2001:
http://www.csd.uoc.gr/~hy558/papers/Rethinking_2001.pdf
You should have read both of them to make the dinner more valuable.
[Interesting articles, which took me back to discussions 20 years ago as
regards connectionless vs. connection oriented networks.]
It is clear from both of these that the basic subject is data
communication over a communication system. Thus the second article
quotes from the first article thus:
"The function in question can completely and correctly be implemented
only with the knowledge and help of the application standing at the
endpoints of the communications system. Therefore, providing that
questioned function as a feature of the communications systems itself is
not possible."
So the basic object under consideration here is a "communication
system".
It is clear from the first article that what is envisaged is a layered
model, (c.f. the conclusion). I would not be surprised if this kind of
thinking was input to the development of the OSI model for data
communications, which does set out to assign to each layer an
appropriate function.
The basic thesis of the article is that functions concerned with, for
instance, security and reliability are best done in the upper layers,
even the top (application) layer, as the application cannot rely
entirely on the lower layers to "do their stuff".
Thus "end to end" is about communication from one application layer to
the peer application layer down through the layers at one system, and
then up through the layers at the other system. So, I would paraphrase
the "end to end design principle" as the "application to application"
design principle.
I note that in models like the OSI model, only the lowest layer have
intermediate systems. (That's why layer 3 is called the network layer).
The article in no way implies that it is the existence of intermediate
systems which is the deciding factor in the design. "End to end" is not
in contrast to "hop by hop".
So, applying this to DNSSEC's PKI, this is clearly an application layer
security system. The system does not depend upon the security or
reliability of any lower layers (or, indeed, intermediate systems). So,
it would seem to fit the "end to end design" of this article.
The second article is a discussion about how the end-to-end design
principle might need to be modified in the light of the realities of the
modern Internet. In the present context of DNSSEC, the discussion of
trust is important.
best regards
David
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