[BBLISA] slow wan link

[Edward Ned Harvey]

> From: bblisa-bounces at bblisa.org [mailto:bblisa-bounces at bblisa.org] On
> Behalf Of Daniel Feenberg
> 
> We aren't continuous pinging, so it is possible that some intervals are
> terrible and others ok.

Based on this, I think it's safe to say, there is a problem from time to
time, and you simply haven't observed at the right time.  (or, wrong time as
it were.)

Here's an anecdote:

I recently faced exactly the same problem.  People complaining of slowness,
particularly when they VPN in and run X gui's (in this case, VNC and NX).  I
couldn't measure any problems.  So I went home, connected a VPN, and
scripted a ping via cron.  Leave it running all day, and in and out of
weeks.  Ping 50 times, record it to a log, repeat every minute.  This way, I
get a good log of all the ping response times throughout the day, and my log
is easily readable to see what times the results came from.

I found, during business hours, for periods of 10 sec or so, the responses
would be like 400ms.  And then maybe for a minute, it would be 100ms, and
then for 3-4 minutes, it might be 20ms.  Totally non-cyclic, no discernable
pattern, the point is, during business hours when everyone's in the office
using the network connection, the ping responses bounce all over the place,
and if any user was sitting at home trying to use it, they would experience
slowdowns and extreme slowdowns (to the point of calling it "unusable" or
"broken") ... They would definitely encounter such a situation in less than
10 minutes, and it might only last a few seconds, or it might last several
minutes.

They were right to complain.  But the only way to measure it was to leave a
continuous metric running, and feed it into an excel graph at the end of the
day.

I decided the best way to process my data was:  Throw away the 2 worst
samples from every minute.  Then average the next 5 worst samples.  Take the
result to mean how bad the connection was during that minute.  Use this as
the data point to feed into excel for that minute.

I got a graph that is near-zero on weekends, near-zero at night.  But it
rises up to a big tall spiky wave every day during business hours, 8-6 EDT.
A very convincing graph to show whoever I need to show it to...