[ih] A comment on the seven layer model

[Steve Crocker]

Jack,

I liked your comment, "I gave up long ago on trying to stuff this into a
7-layer diagram and explain it."

I was part of the original group that designed the first set of host level
protocols for the Arpanet.  From the beginning we thought in terms of thin
layers that provided useful services, with the proviso that others would
build on, ignore and build around, or insert other layers in between as
needed

I turned my attention away from protocol design when I moved to (D)ARPA in
1971 and focused on AI and other topics.  When I re-engaged with the
network architecture and discovered OSI had determined there were
exactly seven layers, I nearly fell over laughing.

The seven layer model has been useful, but it is not complete or definitive.

Steve