1.3    Wired and wireless networks

• types of networks:

• • LAN (Local Area Network) 

    • covers a small area typically only 1 building

    • the using organisation (eg the school) owns all the infrastructure - servers, switches, cables

  • WAN (Wide Area Network)

    • Covers a wide area. The internet is a WAN it covers the whole world

    • Infrastructure not owned by the user - have to pay to use

• factors that affect the performance of networks

• • Bandwidth (how much data can be carried)

  • Transmission Media (wired or wireless) Wired is faster

  • Distance

  • Interference

  • number of users

• the different roles of computers in a client-server and a peer-to-peer network

Client-server  

• • • main computer (server) is accessed by several client computers

    • server controls access, hosts programs acts as central storage

    • Client computers are usually lower spec

Peer-to-Peer

• • • All computers act as client and server

    • they share files, programs and network access

    • a user can access the contents of any other user's computer on the network

• the hardware needed to connect stand-alone computers into a Local Area Network:

• • wireless access points (broadcasts the wireless signal)

  • switches - link computers together send information to specific devices using MAC addresses 

  • routers (routers connect networks together - including connecting to the internet)

  • NIC (Network Interface Controller/Card) on the motherboard of every PC/Laptop

  • transmission media (Ethernet cables, wireless, fibre optic cables)

• the internet as a worldwide collection of computer networks:

• • • DNS (Domain Name Server) - is an internet naming service converts a text web address into a numerical IP address eg ousedale.org.uk becomes 69.172.201.158

    • hosting - allowing remote users to access a specific computer via a network. Host computers can then deliver web pages

    • the cloud - storing data files and running programs on web servers. Google Docs or Office 365 are good examples  

    • Web servers and clients - Servers provide services to clients. Clients request or use services from a server. So in a network a file server will serve the client PCs. On the internet web servers will deliver webpages to requesting computers (pcs, phones, etc)

• star and mesh network topologies

Star has a central server 

Mesh - all computers connected to each other

MORE INFO HERE