There are several types of networks which can be categorized according to coverage area,distance, certain features,devices and others.. The following are must-known types: [b]1)LAN(Local Area Network)[/b]: This network is characterized by: - covers a limited geographic area (e.g: a network inside a school,a company,a store,..etc..) -Always ON - High Speed Connectivity, eg: fast ethernet works at 100Mbps -Uses LAN devices as repeators,hubs,bridges and switches. -Uses LAN technologies as ethernet,Token Ring and FDDI. [b]2)MAN(Metropolitan Area Network)[/b]: This network represents a group of LAN's connected together . e.g: a network connecting different subnetwroks over the whole country. [b]3)WAN(Wide Area Network)[/b]: This include the Internet.It's characterized by the following: -covers a large geographic area -could be Always On as in DSL or On and OFF as in Dial-up modem and ISDN -Limited speed conncetivity relative to LAN's , eg: DSL max. is 2Mbps.( An exception is Cable Modem which operates at very high speeds.) -Uses WAN devices as Routers, Modems and Communication Server (Routers are actually both LAN and WAN devices) -Uses WAN technologies as PPP,x.25, Frame Relay ...... - Requires Serial connections. [b]4)SAN(Storage Area Network)[/b]: This special network is designed as an archive for storage of a company's files, It is used just for just storage and for this sake , it's composed of fibreoptic cables( for fast speed) connecting with tapes or servers with huge size hard drives.. [b]5)VPN(Virtual Private Network)[/b]: This is a virtual network which is made via the interent for the following purposes: -Intranet VPN: a secure communication made between 2 LAN's via the interent. for example: to connect two branches of the same company. This private tunnel is permenant. -Extranet VPN: a secure communication made between the company's network and another company ,having limited access. This VPN is also permenant. -Access VPN: a secure communictaion made between the VPN and a stand-alone PC. For example: between the company's VPN and the manager's home PC. This communictaion is Temporary (requiring logging on and off using a username and password).