'Net traffic: Knowing what we don’t know

>>Determining how fast the Internet is growing is almost a parlor game among pundits these days. Part of the reason is simple practicality: Companies that depend for their livelihoods on supplying or using Internet infrastructure want to better understand growth trends so they can plan investments and growth curves accurately.

Nobody knows how fast the Internet is growing. Another opinion, from IDG News Service:

>>Why didn't we know this until recently? Because there's no system for monitoring and measuring traffic in the 'Net. Individual carriers look inside their own networks, and peering providers (such as Equinix) examine characteristics of traffic that crosses peering points. But although many individual researchers and research institutions are attempting to monitor Internet traffic, none has a panoramic view.

... The best guess, according to experts who attended a conference with me recently, is somewhere between 75% and 100% per year -- but that could be off by as much as 2X (that is, it could be as low as 50% or as high as 200%). One of the foremost researchers in the field, the University of Minnesota's Dr. Andrew Odlyzko, estimates it's between 50% and 60%. The folks at Equinix figure more like 75%. And my own firm recently conducted a study modeling Internet demand at 100%. But the truth is, nobody really knows.