CH2

• Local Area Network (LAN)


  Network confined into 1 single site/building, belonging to an organization, geographically small, using cable/low powered radio (wireless) for connections (twisted pair)
• LANadv


  • Cheaper
  • Expense of installing application software on each pc could be saved by installing the software on the application server attached to a LAN
  • Instead of using many cheap printers for each pc, can use one good quality printer attached to a LAN
  • Efficient
  • File server that's attached to LAN allows user to store and share large files
  • Paperless office - can be save on file server
• LAN disadv


  • Managing can be difficult and complex
  • Malware and hacking can affect the entire network
• HardwareLAN

  • Switch
  • Server
  • Network Interface Card (NIC)
  • Wireless Network Interface Card (WNIC)
  • Wireless Access Point (WAP)
  • Cables
  • Bridge
  • Repeater
• Switch


  Devices within a network that forward packets within the network itself, allow multiple computers to connect to a network through a single node
• Server


  Computer or system that provides resources, data, service to computers, known as clients
• Network Interface Card (NIC)

  Computer hardware component that connects a wire-based computer to a computer network usually the company's network
• Wireless Network Interface Card (WNIC)

  Computer hardware component that connects a radio-based computer to a computer network usually the company's network
• Wireless Access Point (WAP)


  Hardware device on a LAN that allows wireless capable devices and wired networks to connect through a wireless standard (WiFi or Bluetooth)
• Cables

  Coaxial, Twisted Pair, and Fibre optic cables
• Bridge

  Connect multiple devices that has the same protocol & provide communication between them
• Repeater

  Expanding network coverage by combining 2 LAN signals
• Wide Area Network (WAN)

  Network that extends over a large area, created by joining several LAN together, used by company to connect different sites but not owned by the company, provided from a PSTN, use fiber optic Cable, satellite radio, and microwave radio
• WANbenefits

  • Job can be run on a remote computer that had the required application software
  • Data archive that was stored on a remote computer can be access
  • Message could be transmitted electronically to a user on a remote computer
• WAN Hardware

  • Routers
  • Gateways
  • Server
• Router

  Connect 2 network using the same protocol, regulate network traffic, assign private IP address, receive and forward packets from a network using the most efficient route
• Gateway

  Connect 2 network using different protocol, regulate network traffic, assign private IP address, convert data packets from one protocol to another, receive and forward packets from a network
• Internet


  Massive network of networks which are made up of various computers and electronic devices, uses IP protocol, forms a collection of connected networks and is a packet-switched network, all network traffic is made up of packets of data with a source address and destination address, there will be a large number of available paths for the transmission of any data packet
• Internet Hardware


  • Public Switched Telephone Network (PSTN)
  • Dedicated Line
  • Cell Phone Networks
  • Internet Service Provider
• Public Switched Telephone Network (PSTN)


  Switching center that connects all networks together, allows any telephone to communicate with each other, dedicated channel used between 2 points for the duration of the call, connection maintain throughout the telephone call, line remain active even in a power outage
• Dedicated Line


  Permanent connection that is used for business purposes, not commonly shared among multiple users, allows consistent data transfer speed, hence allow users to maintain a continuous, uninterrupted calls
• Cell Phone Networks


  Wireless network spread over large areas called 'cells', each cell is served by at least 1 fixed location transceiver = base station, each cell uses a different set of frequencies to avoid interference, when joined together, cells provide radio coverage over a wide geographical area
• Internet Service Provider


  Organization that provides services for accessing, using the internet
• Client Server Model


  A distributed applications software that splits tasks between the providers of the service (servers) and service requesters (clients), clients sends a request to the server and server find requested data and send it back to client
• Client Server Model


  • More secure, user need username and password, files and resources are centralized
• Types of Servers


  • File Server
  • Email Server
  • Print Server
  • Database Server
  • WebServer
• File Server


  All software and user data files can be stored on the server
• Email Server


  Send, receive, and store emails
• Print Server

  Manages print jobs from network client computers
• Database Server


  Manages a database management system; MySQL
• WebServer


  Manages pages available from a website
• Peer-to-Peer


  Consist of a direct link between 2 computers, therefore not needing any server, no central server, nodes can share files with each other and each nodes will have its own data
• Peer-to-Peeradvantages


  • Faster and more reliable because its a direct connection, no need to authentic users
• Peer-to-Peer- Disadvantages

  • Used in small areas, max nodes = 10, performance issues
• Thin-Client


  A client that only provides input and receive output from the application, chooses an app to run on the server, sends input data to the server when requested by app, received output from the app
• Thin-Client


  • Cheap to expand, hardwares are cheap, all devices are linked to a server, update and new softwares installation done centrally, server can offer protection against malwares and hacking
• Thin-Client

  • High reliance on server, goes down = devices won't work, startup cost is high
• Thick Client


  A client that carries out at least some of the processing itself, chooses an app provided by the server, possibly carries out some processing before running the app on the server and also after receiving the output from the app, possibly download the app from server and runs the app by itself
• Thick Clientadv


  • More robust, can carry out processing even without connection to server, clients have more control, store their own programs and data/files
• Thick Client


  • Less secure, rely on client to keep own data secure, each client need to update data and software individually, data integrity issues, many clients access the same data which can lead to inconsistencies