Networks are divided by size and communication method.

1. (LAN) Local Area Network: connects proximate devices with cables
2. (WLAN) Wireless LAN: likes LAN’s but use wireless technology
3. (WAN) Wide Area Network: connects distant devices/LAN’s

Campus Area Networks (CAN), commonly used at universities, and Metropolitan Area Networks (MAN), commonly used for public places, are between LAN and WAN. A Personal Area Network (PAN) is a very small LAN often using wireless tech (WPAN). When it comes to the size of network we can describe it in several ways. The term network describes almost anything but usually means devices connected using the layer two of the OSI model. A subnetwork and a segment are both part of a network. Although segment has a specific meaning in certain technologies (Coax cable). Finally, we have an Internetwork which is a really big network composed of layer two networks connected via router at layer 3.

Internet is short for Internetwork while “The Internet” refers to the global network of TCP/IP networks. Intranet refers to an internal network that uses TCP/IP. An extranet is like an intranet that allows people from the outside to access it. Given their definitions, we can use these terms quite ambiguously so keep that in mind.