Saturday, August 2, 2014

Operation of IP Data Networks

Hello Friends...Today I am going to discuss about the operation of IP data networks and basics of networks. I hope this post will help you.

  • Recognize the purpose and functions of various network devices such as routers, switches, bridges and hubs.
  • Select the components required to meet a given network specification
  • Identify common applications and their impact on the network
  • Describe the purpose and basic operation of the protocols in the OSI and TCP/IP models
  • Predict the data flow between two hosts across a network
  • Identify the appropriate media, cables, ports, and connectors to connect Cisco network devices to other network devices and hosts in a LAN.
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    Network Devices: 

    HUB:

    Networks using a Star topology require a central point for the devices to connect. Originally this device was called a concentrator since it consolidated the cable runs from all network devices. The basic form of concentrator is the hub.
    hub stackable hub
    As shown in Figure; the hub is a hardware device that contains multiple, independent ports that match the cable type of the network. Most common hubs interconnect Category 3 or 5 twisted-pair cable with RJ-45 ends, although Coax BNC and Fiber Optic BNC hubs also exist. The hub is considered the least common denominator in device concentrators. Hubs offer an inexpensive option for transporting data between devices, but hubs don't offer any form of intelligence. Hubs can be active or passive.
    An active hub strengthens and regenerates the incoming signals before sending the data on to its destination.
    Passive hubs do nothing with the signal.

    Switches:

    Switches are a special type of hub that offers an additional layer of intelligence to basic, physical-layer repeater hubs. A switch must be able to read the MAC address of each frame it receives. This information allows switches to repeat incoming data frames only to the computer or computers to which a frame is addressed. This speeds up the network and reduces congestion.
    ethernet hub swtich
    Switches operate at both the physical layer and the data link layer of the OSI Model. 

    Routers

    Routers Are networking devices used to extend or segment networks by forwarding packets from one logical network to another. Routers are most often used in large internetworks that use the TCP/IP protocol suite and for connecting TCP/IP hosts and local area networks (LANs) to the Internet using dedicated leased lines.
    router
    Routers work at the network layer (layer 3) of the Open Systems Interconnection (OSI) reference model for networking to move packets between networks using their logical addresses (which, in the case of TCP/IP, are the IP addresses of destination hosts on the network). Because routers operate at a higher OSI level than bridges do, they have better packet-routing and filtering capabilities and greater processing power, which results in routers costing more than bridges.
    cisco router


    WAPs (Wireless Access Point)

    A wireless network adapter card with a transceiver sometimes called an access point, broadcasts and receives signals to and from the surrounding computers and passes back and forth between the wireless computers and the cabled network.
    wireless access point
    Access points act as wireless hubs to link multiple wireless NICs into a single subnet. Access points also have at least one fixed Ethernet port to allow the wireless network to be bridged to a traditional wired Ethernet network.
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 Thanks
Atul S Singh
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