What is Computer Network?

To be what it's meant to be computer network should include the following components minimally:

• At least two computers (supplied with network adapters) that have something to share;
• A cable or wireless pathway, called transmission media, for computers to signal each other;
• Rules, called protocols, so that computers can, figuratively, use the unified principle of data communication.

Today's computer networks include not only personal computers, but also other types of computers and a variety of communication devices as well.

Computer networks are often classified by size, distance covered, or structure. The following network classifications are commonly used:

• Local area network (LAN)

  It is a combination of computer hardware and transmission media that is relatively small. Usually LANs do not exceed tens of kilometers in size and is contained within a building or set of a few adjacent buildings:

  

  Today the most popular technologies of LAN organization are Ethernet (wireline LAN) and WLAN (wireless LAN).

• Wide area network (WAN)

  This type of networks interconnects LANs which may be at opposite sides of a country or located around the world: