LIVING IN THE IT ERA

• Computer network


  The interconnection of multiple devices, generally termed as hosts connected using multiple paths for the purpose of sending/receiving data or media
• Server

  A large-capacity device that can store a wide variety of files such as application or data files
• Client

  A computer or device that accesses a server through a network
• Client and server

  Relationship in a client-server model where the client machine sends the request to the server machine
• Client-server model


  • Client sends a request to the server, server looks for the requested data and sends it back as a response
• Both client and server are computers
• Computer network uses addressing to manage the flow of data
• IP address


  An address assigned to a device on a network, composed of four dot-separated decimal numbers ranging from 0 to 255
• MAC address

  A unique hardware identification number which identifies each device on a network, manufactured into every network card or network enabled devices
• MAC address format

  • Six two-digit hexadecimal numbers separated by colons or hyphen
• MAC addresses work like home addresses used for delivery or mailing
• MAC address format

  • C4:AB:B2:9B:7A:8A
• Modulation and demodulation


  Signals travelling between multiple networks are converted into different forms of signals appropriate for transmission over cables or other media
• Modem stands for Modulator-Demodulator
• Hubs broadcast data from one computer to all other units connected to it
• Switches know specific addresses (MAC Address) to send messages, unlike hubs
• Routers calculate the best route for sending data and communicate with each other
• Routers create and maintain a local area network and manage the data entering and leaving the network
• Wireless routers perform the functions of a router and a wireless access point
• Ethernet cables are used with wired networks to connect devices within a local area network
• Network speed is an important aspect that affects internet or network activities
• Network Speed

  Speed is a combination of bandwidth and latency. Bandwidth is the rate of transfer of data over the network, measured in bits, kilobits, or megabits per second. Latency is the time that elapses between a request for information and its arrival, usually measured in milliseconds
• Higher bandwidth networks can deliver more data than lower bandwidth networks given the same amount of time
• Higher bandwidth networks feel faster because they can deliver more data per second
• Latency, measured in milliseconds, is the time that elapses between a request for information and its arrival
• Higher latency means a slower network
• Types of Area Network
• Types of Area Network

  • PAN (Personal Area Network)
  • LAN (Local Area Network)
  • CAN (Campus Area Network)
  • MAN (Metropolitan Area Network)
  • WAN (Wide Area Network)
• PAN (Personal Area Network) surrounds an individual and can be created between Bluetooth devices
• LAN (Local Area Network) connects network devices over a relatively short distance
• CAN (Campus Area Network) spans multiple LANs but smaller than a MAN, such as on a university or local business campus
• MAN (Metropolitan Area Network) spans a physical area larger than a LAN but smaller than a WAN, such as a city
• WAN (Wide Area Network) spans a large physical distance, like the internet