[ih] IEN's as txt

[Joe Touch]

Hi, Jack (et al.),

On 2/10/2017 11:21 AM, Jack Haverty wrote:
> One of the beauties of the TCP/IP design is that the specifications did
> not overspecify. They essentially defined what the formats and protocols
> had to be "on the wire" so that different implementations could
> communicate.  But there were a lot of design decisions still to be made
> by each implementer or system builder

I sincerely wish the phrase "on the wire" would go away. It was NEVER
sufficient to describe a protocol; it defines only the messages that are
exchanged.

A protocol consists of a FSM specification:
    - those messages that are exchanged (sent or received) "on the wire"
    - state
    - events sent/received to the next layer up
    - time events
    - the relationship between the above events and states (a transition
table)

The constellation of items above provides the context in which the
messages have meaning. Without that, they are identical to noise.

Note - TCP got this right early on. The IETF made a serious error in
claiming the "API" wasn't part of a protocol spec for many decades, and
is only now recovering.

But NONE of the above is a decision made by the implementer - they are,
by definition, the aspects of a protocol that ensure that all
implementations interoperate.

Joe