Chpt 11: How do I create a simple network?

• Wired network


  • A network of devices connected by a physical medium, such as cables
• Wireless network


  • A network of devices in which signals are transmitted without the use of a physical medium. The transmission is in the form of electromagnetic waves, such as radio waves
• Wired network


  Data transfer is typically faster and more secure
• Wireless network


  Users can be connected only if they are within range of the network coverage. Obstacles such as walls or metal frames can reduce the strength of Wi-Fi signals
• Traffic


  Transmission of data over a network
• Computer network


  A system of two or more computers that are connected together by a transmission medium for the exchange of data
• Advantages and disadvantages of a computer network

  • Advantages:
  • Shared resources
  • Shared Internet access
  • Shared software
  • Shared storage
  • Communication

  Disadvantages:

  • Initial costs
  • Maintenance costs
  • Security risks
  • Risk of data loss
  • Server outage
• Types of computer networks

  • Local area network (LAN)
  • Metropolitan area network (MAN)
  • Wide area network (WAN)
• Local area network (LAN)

  Network of computing devices connected within a small geographical area, typically within the same building, such as a home, school or office
• Metropolitan area network (MAN)


  Network of computing devices typically spanning across two or more buildings within the same town or city
• Wide area network (WAN)


  Network of computing devices covering a large-scale geographical area, typically across multiple geographical locations
• Wired network


  Network of devices connected by a physical medium, such as cables
• Wireless network


  Network of devices in which signals are transmitted without the use of a physical medium
• Wireless access point (WAP)


  Network hardware that provides a connection between wireless devices up to 100 metres away and can connect to wired networks
• Server


  Computer that shares resources with and responds to requests from devices and other servers on the network
• Comparison between client-server and P2P networks

  • Security
  • Setup cost
  • Storage
  • Application
• Every computer is able to directly share resources with other computers in the network

  Describes a peer-to-peer network
• Each computer has a distinct role in the network


  Describes a client-server network
• Network interface controller (NIC)


  Provides the hardware interface to enable the transfer of data between a device and a network
• Network hub (or hub)


  Device that transmits received packets to all connected devices
• Network switch (or switch)


  Device that constructs a single network by connecting multiple similar networks together
• Router


  Device that forwards packets between separate networks
• Network topology


  Describes the physical layout of a network
• Bus topology


  • A common cable or backbone known as the bus connects all the devices
  • The bus is a medium that allows the transmission of data
  • Devices can communicate with the server, with each other and with devices such as a shared printer
• Ring topology


  • Each computer is connected to two other computers in a ring formation
  • All the data is passed around in the same direction
  • If a failure occurs in the cable or if a computer breaks down, the entire network will fail to function
• Advantages of bus topology

  • Easy and cheap to install as it uses less cabling than other network designs
  • Scalable as new computers can be easily added
  • Can continue to operate even when one of the computers breaks down
  • Works well for small networks
• Disadvantages of bus topology

  • A break anywhere along the bus may disable the entire network
  • The size of the network is limited by the capacity and length of the bus
  • A single bus is unsuitable for networks with many computers; performance slows down as the number of computers increases
• Advantages of ring topology

  • Can operate over larger distances and handle more data than a bus topology
  • Data packets that are sent between two computers will pass through intermediate computers, hence a central server is not required to manage the network
• Disadvantages of ring topology

  • If a computer or cable in the network fails, the entire network may fail as the data cannot be passed on
  • Adding a new computer to the ring network would mean that the whole communication ring needs to be temporarily interrupted
• Star topology


  • Network hardware such as a hub or switch is at the centre of the network with connections to all the other computers
  • The computers will send data to the central network hardware and the hardware forwards the data to the intended destination
• Advantages of star topology

  • The load on each section of cabling is reduced as each computer uses a separate cable from the rest
  • If a fault occurs at a computer or cable, it is easy to isolate the fault and do a replacement without affecting the rest of the network
• Disadvantages of star topology

  • Uses more cabling than other topologies and hence costs more
  • If the central network hardware fails, the entire network fails
• Network topology formed when multiple devices are connected to a network switch

  Star topology