In researching my entry about Intelliverse and VoIP quality, I checked out the folks at Brix Networks. There I found a neat link to a delay and jitter measurement site. They have deployed agents in each of a half-dozen sites around the world (London, Boston, San Jose, Montreal to name a few) and measure the session performance between your location and their endpoint.
The reports coming back from the site: testyouripvideo.com are web-automated and both simple and sophisticated, depending on how detailed you really want to get. This is the simple report on the left, which I have rotated to fit in the blog presentation window. From this report, I can see clearly that my DSL is more than sufficiently fast and stable to satisfy their probe in a Northborough MA <–> San Jose CA test (according to Google, it's 3,091 miles west of here).
The detailed report is also interesting.
Here Brix reports the roundtrip delay (209 ms), latency, packet discards and packet losses in a pie and then in a tabular form for both up and down stream tests. The packet discards and packet loss strike me as being synonyms, but there's no report of a jitter (variability in packet arrival). Maybe that's the packet discard?
The detailed report includes signaling losses too.
I'll try other measurement cities for fun.