Topic 3 Networks (1.3)
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What does LAN stand for?
Local Area Network
Give the characteristics of a LAN
• covers a relatively small geographical area (e.g., a school, home, office) • the hardware is owned by a single person or organisation (that uses it) • only connected to a small number of devices and users
What does WAN stand for?
Wide Area Network
Give the characteristics of a WAN
• covers a wide geographical area (e.g., the internet, a global company) • usually made up of several LANs connected together • uses third party hardware • usually slower than LANs • cost per byte for transmission is much higher on WANs than on LANs
Give the pros of LANs over WANs
• sharing files and communicating with LAN users is easier (shorter distance) • you can share the same hardware on a LAN (printers) • user accounts can be stored centrally, so users can log in from any device on the network
What are the different factors that can affect the performance of a network?
• number of devices connected • bandwidth
How does bandwidth affect the perfomance of a network?
Bandwidth is the amount of data that can be transferred in a given time, eg. 500Mbps. The greater the bandwidth, the beter the network can perform since more data can be transferred at the same time
How does the number of devices connected affect the perfomance of a network?
Available bandwidth is shared between users of a network- too many users or heavy use (streaming videos) may cause congestion/traffic and slow the network you can limit the bandwidth available to individual users to address this
What are two types of networks you need to know?
• client-server • peer-to-peer
How do client-server networks communicate (through what)?
a server and clients
Explain the client-server model
• a client sends a request fto the server (eg. asking for data) • the server processes the request and responds
How do peer-to-peer networks communicate (through what)?
individual devices
Explain the peer-to-peer model
• all devices (peers) have equal status and responsibilities • each peer can act as both a client and a server • they can request resources from other peers and also provide resources in return
What are the types of LAN hardware?
• Wireless Access Points • routers • switches • NIC (Network Interface Controller/Card) • transmission media
What is LAN hardware?
hardware components required to let devices connect and communicate within the WAN
What is the purpose of a Wireless Acess Point (WAP)?
a WAP allows devices to connect wirelessly to a network
What is the purpose of a router?
a router is used to transmit data between multiple networks, allowing devices to connect to the Internet
What is the purpose of a switch?
a switch connects (wired) devices to a LAN. It sends and recieves data requests/packets and transmits this data to the correct device on the network
What is the purpose of a Network Interface Controller/card?
a NIC allows a device to connect to a network
Give some types of transmission media
• ethernet cables • fibre optic cables • coaxial (copper) cables • WiFi
What is the purpose of transmission media?
transmission media help transmit data around the network
What is the Internet?
a networks of computer networks (a WAN)
What is a Domain Name Server?
a system made up of multiple DNS servers
What does the Domain Name Server do?
• made up of multple DNS servers • it converts URLs into IP addresses so computers can communicate with each other • the DNS server is checked for the URL • if it is found, the IP address is returned • if not, it queries another server until it is found