Networking

• A network is a communications system for connecting end systems called hosts
• A local area network (LAN) connects computers that are close together, e.g. by ethernet
• A Wide Area Network (WAN) connects computers in different cities, e.g. by X.15 or ISDN
• A Metropolitan Area Network (MAN) is intermediate in size
• An internet is a connection of two or more distinct LANs or WANs
• An intranet is an internet with all networks belonging to a single organisation