C] Computer Network
I] Definition: A computer network is a set of equipment linked together to exchange information. By analogy with a net (a network is a “small net”, that is to say a small net1), we call a node the end of a connection, which can be an intersection of several connections or equipment (a computer, router, hub, switch).

II] Computer network categories
There are several ways to categorize a computer network.
Computer networks can be categorized in terms of extent:
 Personal Area Network (PAN): Personal network
 Wireless PAN: Wireless Personal Area Network
 Controller Area Network (CAN): Personal network for electronic systems (bus) - Particularly used in the automotive sector
 Local Area Network (LAN): Local network
 Wireless LAN (WLAN): Wireless local network
 Wide Area Network (WAN): Extended network
 Storage Area Network (SAN): Storage network
Computer networks can also be categorized by functional relationship between components:
 Client-server
 Multi-tier architecture
 Three-tier architecture
 Peer-to-peer (P2P or Peer to Peer)

They can also be categorized by network topology:

 Star network
 Bus network
 Ring network
 Toroidal or hypercube network
 Grid network
 Hybrid network