[ih] inter-network communication history
craig at tereschau.net
Wed Nov 6 13:47:42 PST 2019
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
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).
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