[ih] inter-network communication history

[Craig Partridge]

On Wed, Nov 6, 2019 at 2:42 PM Dave Crocker <dhc at dcrocker.net> wrote:

>
> This was where I had my first direct experience with mismatching packet
> sizes at different layers.  It's a classic CS training point, about
> buffer sizes, and the like.
>
> The email transfer mechanism (MMDF) had its own reliable packet layer,
> on top of the "phone" connection and below its email transfer mechanism.
>
> When I initially set such connections up, I discovered they were
> massively inefficient and massively slow.  And massively expensive.  All
> because the MMDF packet size was about 120% of a Telenet packet size.
> As soon as aligned mine with theirs, things went swimmingly. And a lot
> cheaper.
>
>
I maintained later versions of that software.  I don't know if it was in
your version, but by the time I encountered it,
the software had a sorcerer's apprentice bug, where some state glitch would
cause it to send two copies of each
packet instead of one.  As I recall, the bug was so subtle that we never
tracked it down -- just periodically restarted
a channel if it fell into the mode. (I find I want to castigate my younger
self for not investigating further).

Craig


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