[e2e] UDP checksum field?
Cannara
cannara at attglobal.net
Wed Apr 6 20:20:10 PDT 2005
Well, long Erudite reponses are always welcome Ethan, but rather than
Beccaria, even I, as an Italian American, actually prefer Mao: "All political
power stems from the barrel of a gun". :]
Alex
Ethan Blanton wrote:
>
> Cannara spake unto us the following wisdom:
> > Of course, David, but the opposite is: no checksum = no chance of
> > correctness. And, the way NAT and other boxes have been intended and
> > deployed, many people consider them as "ends", making the mythical End-End
> > Principle even more of a fantasy.
>
> I'm not sure exactly what you're trying to say here (I seldom am), but I
> think it misses a very important point. There are in fact a _very_
> large number of applictions which obey the end-to-end principle exten-
> sively. Take as an example class of such applications all SSL or TLS
> streams over TCP.
>
> If [heh] you have a particular axe to grind, you can probably come up
> with some little semantic corner where this is not end-to-end in every
> respect, but it will be just that -- a semantic little corner. SSL over
> TCP performs end-to-end flow control, end-to-end congestion control,
> weak end-to-end integrity checking at the transport layer, and extremely
> robust end-to-end integrity checking (possibly as well as authentica-
> tion) at the application layer. Note that, in this example, each layer
> of the stack provides the largest reasonable set of guarantees it can
> provide, and the ultimate "end-to-end" integrity and authentication
> checks are performed at the _true_ ends of the connection -- the appli-
> cation.
>
> I realize this message is probably futile, but I hope it will end the
> bickering over semantics in this particular thread, and provide some
> food for thought for future such threads. No, the end-to-end principle
> isn't practiced everywhere, but it is far from a "fantasy". And yes, I'm
> sure Ma Bell provided perfect end-to-end service via POTS in 1908 and
> the Internet is so far behind we might as well not even bother talking
> about it, no need to tell me that. Since I use the Internet every day
> (and, miraculously, it works), I'll leave mailing-list theories about
> how it can't possibly work on the shelf for now.
>
> Ethan
>
> --
> The laws that forbid the carrying of arms are laws [that have no remedy
> for evils]. They disarm only those who are neither inclined nor
> determined to commit crimes.
> -- Cesare Beccaria, "On Crimes and Punishments", 1764
>
> ------------------------------------------------------------------------------
> Part 1.2Type: application/pgp-signature
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