[e2e] Protocols breaking the end-to-end argument

William Allen Simpson william.allen.simpson at gmail.com
Sun Oct 25 01:29:30 PDT 2009

Noel Chiappa wrote:
> One was that for _some_ of us, the only 'ISO protocol war' we saw was the
> CLNP/TP4 vs TCP/IP competition.
As an implementor during that period, I have to agree with Noel.

Back in the late '70s, we used X.25 for transmission because that's the
only thing that AT&T (via Telenet, with an 'e') would sell us.  For
satellite data to move from field stations, as a practical matter we
were constrained by availability.

Just as weather data only came in 5-bit baudot coding.  I programmed a
dedicated Alpha Micro (in reality, a minicomputer) to translate to 7-bit
ASCII.  Then, to move it from the Alpha Micro to the Perkin-Elmer
Interdata 7/16, I used IBM bisync.

Before I'd ever heard of TCP/IP, I simply rolled my own "higher level"
packet format, to have a commonality over both X.25 and bisync.  But it
was clear that had to have its own checksum.  Folks seem to forget that
I-O buses were very unreliable.  Corrupted data and dropped interrupts
were common.  An independent transmission layer was crucial.

As I've mentioned recently, it wasn't until later that Merit decided to
implement TCP/IP.  Remember, Merit had its own protocol stack as far
back as the '60s.  ARPA was a relative late-comer around here....

It wasn't until CLNP that I ever perceived a 'war' (or competition).  To
me, it was always apparent that the war wasn't with the protocols per
se, but rather the corporate entities that wanted to control pricing.

When I worked on Michigan's NSFnet bid, we took the money from state
budget line items that were using ISO protocols.  To the politicians,
the potential savings over dedicated telco lines were a big plus.  We
were still in the aftermath of the Reagan Recession.

And that was another element that is often overlooked.  I know this is
less relevant outside the US, but the ISO corporate proponents were
primarily Republicans.  The NSFnet proponents were primarily Democrats,
who were very interested in competition, cost savings, and leveling the
playing field.

> The other was that the E2E paper was not principally intended as firepower in
> the TCP/IP vs X.25 debate, but rather was more intended to be exactly what
> the passage of time has shown it to be - a contemplation of the underlying
> fundamentals of functionality placement, one which would be of lasting value.
Admittedly, I didn't read the paper until much later, so it had little
influence on my thinking.  I vaguely remember a "well, duh" reaction, as
surely every implementor in the field already knew from experience.

But it has continued as an enduring touchstone to help explain these
fundamentals to successive generations.

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