Overview

The Internet is a global network of networks of computers. The "network of networks" concept is also known as internetworking and thus is even incorporated into the name Internet. It refers to the interconnection of many different networks, based on multiple technologies (e.g., Ethernet, token ring, and satellite links), into a single, larger network. Why not instead have one global network based on a single technology? Since no single network technology is best for all situations, there are different network technologies in use in different networks. Mandating a single technology for the global network would be very difficult, technologically, since painful compromises and other difficult decisions would have to be made in designing that single technology. Technology aside, the political obstacles would also be formidable; take the 3G wireless systems as an analogy. Despite the efforts of the International Telecommunication Union (ITU), a single unified global 3G wireless system failed to emerge (for more details, see Chapter 3).

Therefore, the internetworking concept arose as an alternative that would maintain the multiple network technologies while interconnecting the disparate networks into a single network. Thus, advantages of a single large network, such as connectivity between any two computers in the network, would be obtained without requiring a single underlying network to be used. This can be seen as an example of convergence in action, where internetworking was the glue that brought the disparate networks into a single, converged network.

In describing the Internet as a global network of networks of computers,...