Networked Information Systems 1 Advantages of and classified by their size & architecture or design

What is a network? A network consists of two or more computers that are linked in order to: – share resources (such as printers and CD-ROMs), – exchange files, or –allow electronic communications

Why Network? Advantages 1.Resource sharing - internet, printers, software, etc 2.Remote services, ordering, B2B, ATMS, etc. 3.Facilitate communication 3.Facilitate communication – collaborative documents, intranet, group calendaring, , videoconferencing, chat, virtual private networks 4.Data and information sharing 5.Saving money on expensive equipment 5.Saving money on expensive equipment – printers, internet connections, internet cache, CD drives 6.Convenience 6.Convenience – access home directory from any PC, remote control of equipment, networked help desks 7.Security 7.Security – password protection, backups 8.Achieve organisation goals, efficiency, effectiveness, customer service, company image

Networking Networks can be classified by: 1.Their size and architecture 2.Their logical shape, “topology” (bus, star, ring) 3.How they are linked or connected together, (cable, wireless, satellite, radio & infrared systems) 4.Their hardware and software

LANS, local area network Can be cabled (UTP, coaxial*) or wireless. Geographically limited, usually to one site. Longer distances between buildings may need fibre optic cable. LANs usually have one computer designated as the file server Other computers are connected to the network by cables connecting network interface cards in each computer Wireless LAN means computers not confined to one building

Wide Area Network, (WAN) (WAN) – broad geographic coverage (e.g. state-wide, country-wide) WAN, where communications carried by a medium owned by someone else who is not part of organisation Connections use landline data cables (e.g. ISDN, ADSL), satellite. WANS, MAN, state wide network, National Area Network, world wide, eg. internet Virtual Private Networks (VPN) can form a private network using the internet as a communication channel – much cheaper than leased ISDN lines.

Client/Server One computer program (the ‘client’) asks another computer program (the ‘server’) to provide a service, such as looking up and providing data, delivering , sending web pages, bank balances etc. The client/server model can interconnect programs distributed across different locations. Use of multi-tasking File servers, print servers, database servers, DNS’s, Proxy servers

Peer-to-Peer (P2P) networks No server, so costs are lower and installation is simple All computers and users, “peers”, have equal authority and rights Little protection of one workstation against another -Used at home or in small organisations with trusted users -Allows sharing of files, internet connection, printer Issues of speed, security, storage -Internet music sharing networks such as Kazaa are peer-to-peer because there is no central coordinating computer, data and operating software are stored on on each client’s computer.

Internet peer-to-peer network Connect to another’s computer over internet Kazaa software application that supports this Exposes computer to security violations

VOIP Protocol, Network Voice over Internet Protocol, a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP hardwaresoftwareInternettelephone Advantages: User doesn’t pay anymore than what they are paying for their internet.

VPN Network Internet telephony is a combination of hardware and software that enables people to use the Internet as the transmission medium for telephone calls. Internet telephony hardwaresoftwareInternet Problems can be with the quality of the calls Only need a microphone & sound card Other person needs to be on internet