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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: latency vs. packet loss
True, one can certainly think of and even find many situations where they don't correlate, but in real world measurements, it looks like in perhaps 90% of the cases, packet loss between randomly choosen places on the Internet is accompanied by greater than typical latency. I suppose this suggests that saturated links (where the router/switch adds latency by buffering) are a commmon cause of Internet packet loss (vs line errors, etc which would not show this correlation). As a single example, connectivity from here to a popular NSP web site is 40 msec in the morning with no packet loss and 500 msec with 20% packet loss in the afternoon. Routing is the same (through mae-east :-)). > > How well does latency correlate to packet loss on the Internet? For > > example, if one were to pick one of several randomly placed sites on > > the net based on lowest latency to/from point x, what percentage of > > this time would this also yield the site with the lowest packet loss > > to/from point x? My guess is that the correlation is high (due to > > typical buffer sizes). > > Remember latency is also affected by other things, like distance > (you won't get less than 70ms RTT NY<->Lon even on an empty STM-1), > > Also note there are some conditions which cause packet loss which > won't cause ICMP latency (line errors, various IXP overload conditions
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