At 7:25 PM 8/18/94, Steve Dorner wrote:
If I FedEx someone a package, I
can have that package returned to me undelivered, so long as I call FedEx
early enough in the process.
Perhaps we have no choice but to be the USPS. I'd like to at least think
about whether we could be FedEx, though.
In the distinction between ALL MUST, versus SOME MIGHT, we also need to
distinguish between requirements imposed only upon participating UAs,
versus ones imposed on MTAs.
A delete-while-in-transit function a) adds noticeable complexity to MTAs
and b) requires that all in the path participate. Affecting the transport
infrastructure this way is going to be a toughy to get.
Note that FedEx charges rather more for its service than does the USPS.
The problem with this kind of feature is that it can tend to drive email
operating costs in the direction of fedex.
A key error with X.400 was not that it created a lot of silly functions,
it's that it didn't distinguish between core requirements for everyone,
versus highly optional functions for the few. This is a case of confusing
what MRose characterizes as core-vs-edges functionality.
I'll also note that a small comment from Jacob bothers the heck out of me.
He said that the behavior in the receiving UA wasn't specified. This makes
it sound as if the semantics of the function are not clear enough. Sure
hope that was just bad reading on my part.
d/
-----
Dave Crocker
<dcrocker(_at_)mordor(_dot_)stanford(_dot_)edu>
675 Spruce Dr. phone: +1 408 246 8253
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