NETWORK TOPOLOGIES HNC COMPUTING - Network Concepts 1 Network Concepts Topologies.

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NETWORK TOPOLOGIES HNC COMPUTING - Network Concepts 1 Network Concepts Topologies
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Transcript of NETWORK TOPOLOGIES HNC COMPUTING - Network Concepts 1 Network Concepts Topologies.

  • NETWORK TOPOLOGIESHNC COMPUTING - Network Concepts*Network ConceptsTopologies

    HNC COMPUTING - Network Concepts

  • AimsHNC COMPUTING - Network Concepts*Gain a knowledge about network topologies

    Discuss the advantages and disadvantages of different network topologies

    Draw a network topology in Visio

    HNC COMPUTING - Network Concepts

  • What is a network topologyHNC COMPUTING - Network Concepts*In computer terms, topology means the structure or layout of the communications networklogical

    Each workstation on a network is known as a node.

    HNC COMPUTING - Network Concepts

  • What is a network topologyHNC COMPUTING - Network Concepts*Types of Networksring, star, bus, meshCombined

    HNC COMPUTING - Network Concepts

  • Ring NetworksHNC COMPUTING - Network Concepts*

    HNC COMPUTING - Network Concepts

  • Ring NetworksHNC COMPUTING - Network Concepts*An example of a Ring network is a token ring network

    Each node connects to two other nodes creating a circular effect.

    Data travels from one node to another until the correct destination has been reached.

    HNC COMPUTING - Network Concepts

  • Ring NetworksHNC COMPUTING - Network Concepts*

    A node handles every packet that is sent through the network.

    Access is achieved either by means of a token, passed from one node to the other, or by polling

    The two main logical topologies which use this physical topology are Token ring and FDDI.

    HNC COMPUTING - Network Concepts

  • Ring NetworksHNC COMPUTING - Network Concepts*Some advantagesOrderly network because every device has to access the token in order to transmit data.

    Degrades gracefully. Network traffic gradually slows down when busy opposed to Ethernet which grounds to a halt.

    HNC COMPUTING - Network Concepts

  • Ring NetworksHNC COMPUTING - Network Concepts*Some disadvantagesA failure in any cable or device breaks the loop and can take down the entire network.

    Any movement of devices on the network can cause it to fail.

    HNC COMPUTING - Network Concepts

  • Star NetworksHNC COMPUTING - Network Concepts*

    HNC COMPUTING - Network Concepts

  • Star NetworksHNC COMPUTING - Network Concepts*A star network consists of one central switch, hub or computer, which acts as a channel to transmit messages.

    Server dependent - often a mainframe

    HNC COMPUTING - Network Concepts

  • Star NetworksHNC COMPUTING - Network Concepts*Some advantagesA Star Network Topology is very easy to manage because of its simplicity in functionality.

    The problems can be easily located logically in a Star Topology and therefore is easy to troubleshoot.The star topology reduces the chance of network failure by connecting all of the systems to a central node

    It is easier to add additional nodes

    HNC COMPUTING - Network Concepts

  • Star NetworksHNC COMPUTING - Network Concepts*Some disadvantages

    if the central hub fails, all computers connected to that hub would be disconnected.The performance and scalability of the network depends on the capabilities of the hub.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Bus Networks

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Bus NetworksA bus network topology is a network architecture in which a set of clients/nodes are connected via a shared communications line, called a bus.

    A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Bus NetworksA media access method called CSMA (Carrier Sense Multiple Access) is used to handle the collision that occur when two signals placed on the wire at the same time. The bus topology is passive. In other words, the computers on the bus simply 'listen' for a signal; they are not responsible for moving the signal along.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Bus NetworksSome advantagesEasy to implement and extend Requires less cable length than a star topology Cost effective as only a single cable is used.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Bus NetworksSome disadvantagesIf there is a problem with the cable, the entire network goes down. Performance degrades as additional computers are added or on heavy traffic. It works best with limited number of nodes. It is slower than the other topologies.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Mesh Networks

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Mesh NetworksIt allows for continuous connections and reconfiguration around broken or blocked paths by hopping from node to node until the destination is reached.

    A netlike communications network in which there are at least two pathways to each node. A fully meshed network means that every node has a direct connection to every other node.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Mesh NetworksSome advantages

    Self-healing: the network can still operate even when a node breaks down or a connection goes bad. As a result, a very reliable network is formed.

    HNC COMPUTING - Network Concepts

  • HNC COMPUTING - Network Concepts*Mesh NetworksSome disadvantages

    Setup time can be quite time consuming.Expensive

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  • TasksHNC COMPUTING - Network Concepts*

    Write notes and/or store web links regarding token ring networks.

    Find out about physical topologies and logical topologies. make notes.

    Research into different topologies, including combined topologies.

    Select one topology and draw it in Visio

    HNC COMPUTING - Network Concepts

  • ConclusionHNC COMPUTING - Network Concepts*Gained knowledge about network topologies.

    Discussed the advantages and disadvantages of different network topologies.

    Created a drawing in Visio to represent a network topology

    HNC COMPUTING - Network Concepts

    *Multistation Access Unit, a hub to which nodes connect on a Token Ring network.FDDI (Fiber Distributed Data Interface) technology is network access technology over fibre optic type lines. It is in fact a pair of rings (one is called "primary", the other which makes it possible to capture errors from the first, is called "secondary") FDDI is a token ring network with detection and correction of errors (it is here where the secondary ring becomes important). *CSMACarrier Sense Multiple Access (CSMA) is a probabilistic Media Access Control (MAC) protocol in which a node verifies the absence of other traffic before transmitting on a shared physical medium, such as an electrical bus, or a band of electromagnetic spectrum."Carrier Sense" describes the fact that a transmitter listens for a carrier wave before trying to send. That is, it tries to detect the presence of an encoded signal from another station before attempting to transmit. If a carrier is sensed, the station waits for the transmission in progress to finish before initiating its own transmission."Multiple Access" describes the fact that multiple stations send and receive on the medium. Transmissions by one node are generally received by all other stations using the medium.