Types of Network ComputerStand-alone Computer

A computer that is not connected to a network is called a stand-alone computer.

Types of Network ComputerNetworked Computer

A computer connected to one or more computers on a network.

Types of Network ComputerNetworked Computer

A networked computer needs to be fitted with a Network Interface Card (NIC). The NIC can be wired or wireless.

Types of Network ComputerServer

A computer or device on a network that manages network resources. Examples include:File ServerPrint ServerWeb ServerMail ServerDatabase Server

Types of NetworkClient-Server

Advantages:All files stored centrally, peripherals controlled centrallyCentralised back-ups

Disadvantages:Expense of server hardwareIf server fails, the network will be disruptedAdditional network resources such as specialist OS& network manager required

Types of NetworkClient-Server

Server: provides a resource across a networkClient: a computer requesting a service on the network

A file server shares up centrally stored files to the client

A web server hosts web sites internally (intranet) or externally (Internet)

A print server connects clients with printers

Types of NetworkPeer-to-Peer

A network consisting of two or more connected PCs which share resources

Could be as simple as 2 computers connected using USB to transfer files

Bit Torrent sites are an example of a P2P network – the same file can be shared by multiple peer computers making downloads faster

Types of NetworkPeer-to-Peer

Advantages:if one peer fails, there are others which can be usedcheaper to build as no server required

Disadvantages:security is poor, difficult to manage levels of access rights and issues with virusesnot possible to back-up

Range of NetworkLocal Area Network (LAN)

A Local Area Network is a network of connected computers which spans a small area such as:RoomBuildingOfficeWider site (such as a school or hospital)

Range of NetworkWide Area Network (WAN)

A Wide Area Network is a network computers which spans a large geographical area

Generally 2 or more LANs connected together through telephone lines, leased lines or satellites

Largest WAN is the Internet

The InternetThe Internet is a global network of computers

The Internet is decentralised

No one owns the Internet

The InternetThe Internet is not the same as the World Wide Web (The WWW is the hyperlinked information that is built on top of the Internet)

An Internet Service Provider (ISP) is a company which provides users with Internet access

Trends in NetworkingIncreasing BandwidthAverage UK fixed broadband average:2012 = 9 Megabits / sec (Mbps)2013 = 15 Mbps2014 = 19 Mbps2015 = 23 Mbps2019 = 50 Mbps (predicted)

Transmission MediaOptical cables offer much faster data speeds

Trends in NetworkingMobile Network Speeds3G = 0.5 – 1.5 Megabits / sec4G = 2 – 12 Megabits / sec5G = up to 1 Gigabit / sec (expected 2020)

Improved WiFi standards2003 – 802.11g up to 54 Mbps2009 – 802.11n up to 600 Mbps2015 - 802.11ac up to 1.3 Gbps2019 - 802.11ax could offer over 10 Gbps