[BBLISA] Jim Gettys on Internet buffer bloat: smoke ping

[Tom Metro]

Jim mentioned a few tools for diagnosing packet delay, such as "smoke
ping." Did anyone catch the full name of those tools? (Not Netalyzer,
which I'm already familiar with.)

I had a packet latency problem (occasional spikes into the seconds) on a
wireless LAN a while back, and looked around for tools at the time and
didn't find anything that really did what I wanted. I ended up throwing
together a small tool using a ping library for Perl. It pinged a target
host periodically and output a timestamp and an ASCII bargraph that was
proportional to the latency. It also, when the latency exceeded a
threshold, output a tone that varied proportional to amount of latency.

Eventually the problem was traced back to an incorrectly configured QoS
setting where the bandwidth limit was set in excess of the WAN speed.
This was apparently filling up the router's buffers, and spilling over
to its ability to pass packets between the WLAN and the LAN.

 -Tom

-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/