Scott,

There is an often quoted statistic of the Internet doubling every 12 months. If we look at a snippet of [...] I've see a few guesses on this list as to a doubling rate, but I'm wondering if there is a way to judge this growth in some sort of external and non-proprietary way.

Perhaps a relationship between "average traffic" and the number of routes? This probably wouldn't hold in the specific (because of the degree of use of CIDR at a particular ISP), but may hold in the aggregate. Thinking caps?

It used to be that there were three ways to measure the growth of the Internet, these being the growth in the monthly total NSFnet backbone traffic, the size of a full forwarding table (or the size of the Merit PRDB, which was related to the size of a full forwarding table by a fairly constant factor), and the number of hosts discovered by the DNS host count. These all grew in near-enough lockstep, with doubling times consistently in the range of 10 to 15 months over a period of many years, that one could come to the conclusion that they were actually telling you something about the global whole, even though any of those measurements by itself might have been less convincing. The deployment of BGP4 pretty much screwed up the size of a full forwarding table as a measure of anything of greater significance than the size of a full forwarding table (which, of course, now also varies in size and content depending on where you measure it). While the jury is still out on whether we've actually caused a fundamental change to the way in which global routing information grows, or whether we're just in transition to a shallower curve, where the growth in global routing information will again match the growth rate of the Internet as a whole but with a smaller constant of proportionality, it is almost certainly the case that the last couple of years of data won't tell you much of anything at all. This leaves the DNS host counts. I haven't seen any results from these for a long time now (are they still done?), but in any case this was always the least satisfactory measure of the three because of the large number of things you could list as being wrong with them. These were included in plots I saw mostly because they happened to often match the other two growth rates, if they hadn't I suspect they would have been discarded without further concern. You could certainly measure your own traffic growth rate, but to know if this represented a sample consistent with the global growth rate you'd need other peoples' data to compare it to, and since the latter comparison could be construed by the simple minded (including marketing people and the press, no doubt) to have connotations with respect to "market share" no one in their right mind is going to want to participate in an I'll-show-you-mine-if-you-show-me-your's competitive rathole like this. You could also try using measurements of NAP traffic to characterize the global whole, but in fact without other data to correlate this with you've still got to wonder if this is representative of anything more than just the growth rate of NAP traffic. I personally think we've sort of seen the end of a golden age of Internet building, and that hope of maintaining any sort of macro-level sense of the scale and nature of the whole thing being built (rather than just guarded views of individually-owned chunks of it) is diminishing. I do find it exceedingly annoying that all sorts of bits and pieces of the most wonderful, insightful trivia get buried inside internal reports where people who could make use of the tidbits in understanding what we've built never see them (who would have expected, for example, that it would be possible to sustain average loads above 90% of full over 10 minute periods on a T3 backbone circuit with less than a 0.1% output drop rate using a router which had less than 8 milliseconds of output buffer for the interface). Of course there were always people, who I didn't disagree with, who consistently asserted that many sorts of useful data about the network they were a part of were no ones' business but their own, but if you're kind of fond of learning what works and how, and what doesn't work and why, it is less fun than it used to be. Sometimes it is hard to get rid of the bath water without dumping the baby with it. I'd note one thing, however:

growth and for planning. Obviously several things in the past year have occured that have greatly shortened this time. Amongst

In fact you can't know even this, since you haven't measured it you can only guess. It is always the case, when you're living on an exponential growth curve, that this year's growth looks pretty humungous compared to last year's, and next year's projections look even more amazing, but this doesn't tell you whether the slope on a log-linear plot has actually turned up or not. And the growth of your own service over the past year in particular is going to be a bit dangerous to extrapolate to anything general from, since it has grown from a point near zero only a year ago to really big now you've probably got severe divide-by-zero problems with this data. The data from years gone by at least have the merit that they were in fact measured to be so. If I were guessing I'd rather gamble on an extrapolation of something I knew to be "true" last year, rather than try to intuit how things might have changed this year, since intuition is notoriously fallable. I suspect this is why the 1 year doubling time still persists. Dennis Ferguson