Internet Architecture- Lecture 1

Internet Architecture
Lecture 1:What Is the Internet?

Introduction
One of the most frequently asked questions about the Internet is "Who runs it?" The truth is that no centralized management of the Internet exists. Instead, it is a collection of thousands of individual networks and organizations, each of which is run. Each network cooperates with other networks to direct Internet traffic so that information can pass among them. Together, these networks and organizations make up the world of the Internet.
The Internet isn t a single network; it is a vast network of networks. No single person, group, or organization runs the Internet.
The Internet was created by the Advanced Research Projects Agency (ARPA) and the U.S. Department of Defense for scientific and military communications.
The Internet is a network of interconnected networks. Even if part of its infrastructure was destroyed, data could flow through the remaining networks.
The Internet uses high-speed data lines, called backbones, to carry data. Smaller networks connect to the backbone, enabling any user on any network to exchange data with any other user.
Internetworking: the process of connecting separate networks.

How the Internet Works: TCP/IP
The networks communicate with one another based on certain protocols, such as the Transmission Control Protocol (TCP) and the Internet Protocol (IP). More and more networks and computers are being hooked up to the Internet every day.
Tens of thousands of these networks exist, ranging from university networks to corporate local area networks to large online services such as America Online and MSN. Every time you tap into the Internet, your own computer becomes an extension of that network.