smart devices, as part of their intelligence, have communication skills and therefore also mandate some network capacity. More and more of the typical busi- ness professionals today-many of whom work in the high-tech sector and there- fore qualify as early adopters-already have an average of at least five devices each (e.g., PCs, mobile phones, PDAs, MP3 players, pagers, smart clothing). We're look- ing toward a future of more and more devices communicating with one another, and someday there will be thousands of such devices for each human, not to men- tion an enormous array of intelligent sensors monitoring each and every move of the environment, of humans, and of animals. As discussed in this book's introduc- tion, just about everything you can think of is having some kind of intelligence built into it in order to add value to your life. Devices are now beginning to com- municate with each other more than people are communicating with each other, and this situation promises to become further exaggerated in the future. Communications Backbone Trends Growth and changes in traffic necessitate changes in the network backbone. Before the Internet became commercialized in 1995, backbone traffic was growing at a compound rate of about 6% to 10% per year, which was not much different from the traffic growth on the PSTN and in voice communications. But since that com- mercialization in 1995, traffic has been increasing at a compound annual rate of more than 100%, slowing for the first time in 2005, and as of early 2006, the aver- age amount of traffic on the Internet's backbones was 1Tbps. Backbone trends will be further complicated and driven by the advent of advanced applications that consume bandwidth in petabits per second (1Pbps = 1,000Tbps). Online virtual reality, for instance, would require 1Pbps to 10Pbps additional capacity on the backbone; three-dimensional holography would require 30Pbps to 70Pbps additional capacity; metacomputing, or grid computing (i.e., the harnessing of multiple computers together to c