1.13 The Internet

1.13 The Internet

In Figure 1.3 we showed an internet composed of two networks ” an Ethernet and a token ring. In Sections 1.4 and 1.9 we talked about the worldwide Internet and the need to allocate IP addresses centrally (the InterNIC) and the well-known port numbers (the IANA). The word internet means different things depending on whether it's capitalized or not.

The lowercase internet means multiple networks connected together, using a common protocol suite. The uppercase Internet refers to the collection of hosts (over one million) around the world that can communicate with each other using TCP/IP. While the Internet is an internet, the reverse is not true.