JiM Ge TTys
in pulling on a string
to figure out why
my home router
was misbehaving so
badly, i discovered
that all operating
systems—Linux,
Windows, and
Macintosh alike—
also are guilty
of resorting to
excessive buffering.
This phenomenon
pervades the whole
path. you definitely
can’t fix it at any
single location.

ceRf: I assume you weren’t the only one making noises about these sorts of problems?

Ge TTys: I had been hearing similar complaints all along. In fact, Dave Reed [Internet network architect, now with SAP Labs], about a year earlier had reported problems in 3G networks that also appeared to be caused by excessive buffering. He was ultimately ignored when he publicized his concerns, but I’ve since been able to confirm that Dave was right. In his case, he would see daily high latency without much packet loss during the day, and then the latency would fall back down again at night as flow on the overall network dropped.

Dave Clark [Internet network architect, currently senior research scientist at MIT] had noticed that the DSLAM (Digital Subscriber Line Access Multiplexer) his micro-ISP runs had way too much buffering—leading to as much as six seconds of latency. And this is something he had observed six years earlier, which is what had led him to warn Rich Woundy of the possible problem.

ceRf: Perhaps there’s an important life lesson here suggesting you may not want to simply throw away outliers on the grounds they’re probably just flukes. When outliers show up, it might be a good idea to find out why.

nicK WeaVeR: But when testing for this particular problem, the outliers actually prove to be the good networks.

GeTTys: Without Netalyzr, I never
would have known for sure whether
what I’d been observing was anything
more than just a couple of flukes. Af-
ter seeing the Netalyzr data, however, I
could see how widespread the problem
really was. I can still remember the day
when I first saw the data for the Inter-
net as a whole plotted out. That was
rather horrifying.