Re: deprecating Postel's principle- considered harmful

[Joe Touch <touch@xxxxxxxxxxxxxx>]

On May 7, 2019, at 1:29 PM, Barry Leiba <barryleiba@xxxxxxxxxxxx> wrote:

It just erroneously blames Postel for sloppy implementations.

Blaming the principle isn't the same as blaming Postel; the point here
isn't so much that "Postel was wrong" as it is that there are many
consequences of adhering to that principle that Jon didn't anticipate.

I’ve already noted this in earlier versions of this thread, but to restate:

Protocols are, by definition, a set of rules - rules for BOTH sender and receiver - that enable communication (sharing of state) [Shannon/Weaver]. 

The point of the Postel Principle is to stay INSIDE the lines as a sender, and allow right up to the lines for the receiver.

It is about interpreting the (often unavoidable) aspects of protocol that are ambiguous.

*NONE* of it is about tolerating bugs or errors, nor is it about allowing arbitrary behavior for senders. 

It can’t be - again, protocols are rules. Take away the rules and you take away the ability to communicate.

Joe