Thursday, 4 May 2017

Network Topology - Description and Type of Typologies

Network Topology

Network Topology is a diagram or map which shows about the layout of network.
In computer network, network topology is the brief description of arrangement of the devices (Router, Switch, Hub, PC's, etc) and cables which are connecting these devices with each other in the network.
Network Topology is defined into two major parts
  1. Physical Network Topology
  2. Logical Network Topology

    Logical Network Topology

    Logical Network Topology is a type of topology in which only the over view of devices is show which means that how many devices are connected in the network and what type of those devices are.

    Network Topology - Logical Topology

    Physical Network Topology

    Physical Network Topology is a type of topology in which all the devices and cables are show completely with their complete locations and paths.

    Network Topology - Physical Topology

    There are different types of Physical Typologies
    • Point to Point Topology
    • Ring Topology
    • Star Topology
    • Bus Topology
    • Mesh Topology
    • Tree Topology

      Point to Point Topology

      In this topology two devices connect with each other with the direct link without any dedicated device or any third party.
      Examples of Point to Point Topology are
      Telephone Connections

      Network Topology - point to point topology

      Advantages of Point to Point Topology

      • Very low cost to setup
      • Very easy to setup connection
      • Suitable for networks which are temporary
      • Used to connect two areas using high speed link

      Disadvantages of Point to Point Topology

      • Growth is limited in these networks
      • There is no centralized administration
      • Compromising and very week security

        Ring Topology

        Ring Topology is a type of topology in which all the devices or nodes are connected with each other and forms a close circle. If any cable or device fails whole network will shutdown. All the packets should have to pass from each node to reach their destination.

        Network Topology - ring topology

        Advantages of Ring Topology

        • All packets travel in same direction and data travel speed is very high
        • Packet transmission is simple because all packets travel in same direction
        • New node consume very low bandwidth due to which networks speed remains better
        • Collision domain does not occurs because nodes transmit data only when the link is free
        • Only one node can transmit data at same time

        Disadvantages of Ring Topology

        • If one node or link fails all the network will shutdown
        • If changes are made in the networks it effects the whole network
        • Packets sent from sender should have to pass from all the nodes to reach the destination
        • All nodes are completely dependent on the link between them

          Star Topology

          Star Topology is used mostly. In this topology all the nodes are connected with central devices which may be switch or hub. If that central device fails then the whole network will shutdown.

          Network Topology - star topology

          Advantages of Star Topology

          • Star Topology is easy to set
          • it gives much better performance than other typologies
          • If organization wants to expand their network then this topology allows easy method to expand
          • If any node fails it does not effects or shutdown the networks
          • Administrator can easily add or remove any node form that network
          • If any failure occurs it can be easily detected due to centralized administration
          • It is more secure than other typologies because analysis of traffic is easy in this topology

          Disadvantages of Star Topology

          • Star Topology is very expensive because dedicated devices are required to establish this topology
          • huge amount of hardware is required
          • All the operations performed in this topology are completely dependent on central device and if that device fails then whole network will shutdown
          • Addition of new nodes is dependent upon the capacity and bandwidth of central device

            Bus Topology

            Bus topology is a topology in which all the devices are connected with central cable or backbone cable. Bus topology is reliable topology and if any one node fails it does not effect the network and data transmission stay active.

            Network Topology - bus topology

            Advantages of Bus Topology

            • Implementation of bus topology is very easy
            • In small networks it is suitable
            • Mostly used in temporary networks
            • Much less expensive than other

            Disadvantages of Bus Topology

            • Length of cable is limited due to which limited number of nodes can be added to that topology
            • If number of nodes are less then it's performance is better
            • If number of nodes increases then performance and speed of network decreases
            • This topology is used in the networks having less traffic
            • All the devices are dependent on the central cable and if that cable fails whole network will shutdown
            • All nodes can see the packets travelling through bus due to which security of network compromises
            • It is very difficult for administrator to troubleshoot problem in the network

              Mesh Topology

              In mesh topology each node and network device is directly connected with each other and form multiple links so that if one link or node is down then data will travel from other node or link.
              Data can take more than one paths to reach the destination form the source.

              Network Topology - mesh topology

              Advantages of Mesh Topology

              • All the nodes and devices are connected in such a way that at the same time data can be sent to more than one nodes
              • If one node or links fails it will not stops the transmission. Transmission occurs from the other nodes and links
              • Mesh topology can handle heavy network traffic due to multiple links
              • Point to Point connections can also be established and they will help to identify the problems in the network
              • This topology does not affect by the number of nodes

              Disadvantages of Mesh Topology

              • It need continuous observation and maintenance
              • Very expensive to install
              • Complex cabling is required

                Tree Topology

                 Tree topology is a three level topology. Tree topology is the combination of two typologies which are star and bus typologies. It is also called Hybrid Topology.

                Network Topology - tree topology

                Advantages of Tree Topology

                • Easily expandable
                • Troubleshooting is easy
                • Each level is connected directly with the root node with point to point connection
                • If one level fails remaining levels doesn't effected

                Disadvantages of Tree Topology

                • Dependent on main cable
                • Expansive to install and maintain
                • Addition of new nodes depend upon the bandwidth of the main cable

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