3.5 Computer Networks

Two or more computers connected together

• share files • share internet connection and hardware devices • improved communication • roaming profile • central backup

• reliance on networked sources • expensive hardware • risk of spread of viruses • specialist staff often required (maintenance & installation)

Personal Area Network Connect electronic devices within a user’s immediate area Wired or wireless Mouse, keyboard, printer, headphones

Local Area Network Network contained within one building or site

Wide Area Network Computer network that extends over a large geographical area, connecting LANs

Star & bus

A network device that forwards data packets between computer networks

A device used to connect two different networks, especially a connection to the internet

A global computer network of interconnected networks using standard communication protocols

A high speed internet connection

A network security system designed to prevent unauthorised access to or from a private network

A set of rules that allow devices and computer networks to communicate securely and transfer data reliably

Data transmitted via wired LAN

F.O is faster using protons rather than electrons Plus not a fire hazard

=group of wireless network protocols Using radio signals

Wireless access point Enables mobile devices to have wireless access to wired network

IP is an identifier of data TCP/IP tgt to connect devices UDP/IP tgt to route and transport data

TCP connect devices and labels packets UDP sends packets

file transfer protocol Legacy communication to transfer files to another computer

Both transfer electronic messages SMTP: from client to servers or between servers IMAP: only from an email server to client

Application Transport Internet Link

• LAN links only in one site • speed of LAN transmission is higher than WAN with traffic • WAN are typically public networks, LANs private, hence no need encryption

a set of rules that allow computer networks to communicate securely and transfer data reliably