I thought would be more sane too. I see mentioned online that PDV is a

gaussian distribution (around mean) but it looks more like half a bell curve, with most numbers near the the lowest latency seen, and getting progressively worse with

less frequency.

At least for DSL connections on good ISPs that scenario seems more frequent.

You "usually" get the best latency and "sometimes" get spikes or fuzz on top of it.

by the way after I posted I discovered Firefox has an issue with this test so I had

to block it with a message, my apologies if anyone wasted time trying it with FF.

Hopefully i can figure out why.

On Thu, May 7, 2015 at 9:44 PM, Mikael Abrahamsson <swmike@swm.pp.se> wrote:

On Thu, 7 May 2015, jb wrote:

There is a web socket based jitter tester now. It is very early stage but
works ok.

http://www.dslreports.com/speedtest?radar=1

So the latency displayed is the mean latency from a rolling 60 sample buffer, Minimum latency is also displayed. and the +/- PDV value is the mean difference between sequential pings in that same rolling buffer. It is quite similar to the std.dev actually (not shown).

So I think there are two schools here, either you take average and display + / - from that, but I think I prefer to take the lowest of the last 100 samples (or something), and then display PDV from that "floor" value, ie PDV can't ever be negative, it can only be positive.

Apart from that, the above multi-place RTT test is really really nice, thanks for doing this!

--
Mikael Abrahamsson email: swmike@swm.pp.se