<p>[Graphic: map to come]</p><p>Cyberwarfare 101: The Physiology of the Internet</p><p>Editor’s note: This is part of a series of analyses on the emergence of cyberspace as battlespace.</p><p>Summary</p><p>Unlike conventional kinetic warfare -- in which physical force is used to destroy an enemy, his will and his means to fight -- Cyberwar would seem to be more a matter of destroying data. Still, there are more physical aspects of the Internet than meet the eye.</p><p>Analysis</p><p>There are few areas of the civilized world left untouched by the Internet. It feels like a strange new force, intangible but powerful, seeming to exist in some metaphysical dimension. But cyberspace does have physical characteristics -- other components less obvious than computers and keyboards that can nonetheless be seen, touched and put out of commission. Following are a few of the Internet’s most critical parts:</p><p>Undersea Cables Resting on the ocean floor, communications cables with fiber-optic cores allow the massive data flow that connects national networks to the global network. While these connections are critical to a nation’s ability to connect to and use the Internet effectively, their worldwide distribution is uneven. The highest concentration of cables are those connecting to networks in North America, specifically the United States, followed by Europe and East Asia. Countries in these geographic areas enjoy a very high level of communication system redundancy. If a cable connection is lost, their networks can continue functioning with little reduction in performance. Countries in regions that have yet to develop redundant capacity (due to a lack of resources or demand) are far more vulnerable to communication interruptions, including connectivity to the Internet. </p><p>Internet Exchange Points The ability just to connect to the Internet is not enough. While the Internet itself is a massive global network, it is composed of numerous regional, national, subnational and corporate networks. These networks can be inherently and vastly different. On their own, they cannot interact and communicate outside of their immediate virtual environments. In order for the network as a whole to work properly, these subnetworks must be banded together so that communications from around the world can find efficient routes of transmission. To accomplish this, a piece of physical infrastructure is integrated at meeting points between networks called Internet exchange points. An Internet exchange point contains numerous network switches. These allow several different Internet service providers (ISPs) to wire their respective infrastructures together, and if necessary translate their own internal languages into forms understandable to other networks. Backbones Behind each Internet exchange point is a nation or region’s backbone network. This backbone is the conglomerated network of all the connected individual ISPs' networks -- essentially the phone lines, coaxial cables and fiber-optic connections that tie all of the country or region's connected computers and servers together.</p><p>DNS Servers A critical reference tool for Internet users are the world's 13 “root” Domain Name System (DNS) servers. Globally dispersed (most are in the United States), DNS servers essentially act as the Internet's collective phone book, translating Domain Names (e.g., www.stratfor.com) into numerical Internet Protocol (IP) addresses (which look something like 62.71.268.14). These IP addresses often change over time, so the address of a regularly visited Web site might vary, requiring constant check-ins with a DNS server. This makes the DNS database one of the largest and most frequently accessed databases on the planet -- serving a function crucial to the operation of the Internet. One individual can easily access a DNS server a hundred times in the course of a day, which adds up to billions of daily requests worldwide.</p><p>Related Links:</p><p>Other Cyberwarfare 101 pieces [5] Other cyberwarfare pieces previously published on the site Cyberwarfare special topic page</p>