Networks 2


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Networks 2

  1. 1. A quick revision on the OSI model.Network devices.Networks topologies.
  2. 2.  It is a way of sub-dividing a communications OSI model system into smaller parts Application layer called layers. Presentation layer A layer is a collection of conceptually similar Session layer functions that provide Transport layer services to the layer above it Network layer and receives services from the layer below it. Data link layer Physical layer
  3. 3.  Helps users understand the big picture of networking. Helps users understand how hardware and software elements function together. Makes troubleshooting easier by separating networks into manageable pieces. Defines terms that networking professionals can use to compare basic functional relationships on different networks.
  4. 4. Repeater.Hub.Bridge.Router.
  5. 5. A repeater connects two segments of your network cable. It retimes and regenerates the signals to proper amplitudes and sends them to the other segments. Repeaters require a small amount of time to regenerate the signal. Repeaters work only at the physical layer of the OSI network model.
  6. 6.  Is a device for connecting multiple devices together and making them act as a single network segment. Any packet entering any port is regenerated and broadcast out on all other ports. Hubs are classified as Layer 1 (physical layer) devices in the OSI model.
  7. 7. A bridge reads the outermost section of data on the data packet, to tell where the message is going. It reduces the traffic on other network segments, since it does not send all packets. Bridging occurs at the data link layer of the OSI model, which means the bridge cannot read IP addresses, but only the outermost Hardware Address of the packet.
  8. 8. A bridge and switch are very much alike; a switch being a bridge with numerous ports. Switch or Layer 2 switch is often used interchangeably with bridge. Switchesmay operate at one or more OSI layers, including physical, data link, network, or transport layer.
  9. 9. A router is used to route data packets between two networks. It reads the information in each packet to tell where it is going. Routing occurs at the network layer of the OSI model. Which means that Routers can read IP addresses .
  10. 10.  Routers do not send broadcast packets or corrupted packets. If the routing table does not indicate the proper address of a packet, the packet is discarded.
  11. 11. Bus topology.Star topology.Ring topology.Mesh topology.
  12. 12.  Bus networks use a common backbone to connect all devices.
  13. 13.  Easy to install.  Ifthere is a problem Add and remove with the cable, the entire devices is simple. network breaks down. Cost effective; only a  Sending data takes long single cable is used. time. Easy identification of  Limited cable length and cable faults. number of stations.
  14. 14.  Many home networks use the star topology. A star network features a central connection point called a "hub" that may be a router or a switch. Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cables will only take down one computers network access and not the entire LAN.
  15. 15.  Better performance.  High dependence of the Isolation of devices. system on the central hub. Easy to install and wire.  Network size is limited by No disruptions to the the number of connections network when connecting that can be made to the or removing devices. hub.
  16. 16.  In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise").
  17. 17.  Very orderly network where  Add/Remove devices. every device has access to the  Limited number of token and the opportunity to devices. transmit.  High cost. Performs better than a bus topology under heavy  Time. network load. Easy to install.
  18. 18.  Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. Some WANs, most notably the Internet, employ mesh routing.
  19. 19. A mesh network in which Partial mesh networks also existevery device connects to every in which some devices connectother is called a full mesh. only indirectly to others
  20. 20.  Low rate of failure.  Add/Remove devices. Low time consuming  Limited number of in sending data. devices. More secured.
  21. 21. Thank You