CLASSIFICATION OF NETWORK | INTERNET SERVICES | NETWORK ARCHITECTURE | NETWORK TOPOLOGY | INTERNET


Network Topology



Define Network :

-A computer network is a communication system that connects two or more computers and their peripheral devices to exchange information and share resources.




What is a network topology?
A network topology refers to:
-The layout of the computers and devices in a communications network or
-The configuration of a network that consists of cables, computers, and other peripherals.

What is a physical topology?

-The physical topology of a network refers to the configuration of cables, computers, and other peripherals.


What is a logical topology?
-The logical topology of a network refers to the architecture, that is the way in which the network appears to the devices that use it.

Three (3) basic types of network topology:
-Star Network.
-Bus Network.
- Ring Network.
Bus Network Topology



-A bus network consists of a single central cable (backbone/trunk), to which all computers and other devices connect (node).
-The bus is the physical cable that connects the computers and other devices.
-The bus in a bus network transmit data, instructions, and information as a series of signal.
-Those signals are sent as electrical pulses that travel along the length of the cable in both directions.
-Each devices is connected to the single bus cable through T-Connector.
- A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable.

Advantages:

1. Bus networks are inexpensive and easy to install.

2. Computers and other devices can be attached
    and detached at any point on the bus without
    disturbing the rest of the network.

3. Failure of one device usually does not affect the
    rest of the bus network.

Disadvantages:

-1. There might be disruption when computer or
    other devices are added or removed.

2. Because all systems on the network connect to
    a single cable or backbone, a break in the cable
    will prevent all systems from accessing the
    network.

3. It is difficult to identify the problem if the entire
    network shut down.
Ring Network Topology



-On a ring network, a cable forms a closed loop (ring) with all computers and devices arranged along the ring.
-Data transmitted on a ring network travels from device to device around the entire ring, in one direction (clockwise or counterclockwise)
-Token passing is one method for sending data around a ring
-Each device takes a turn sending and receiving information through the use of a token.

Advantages:
1. The transmission of data is relatively
    simple as packets travel in one direction only.

2. Cable faults are easily located, making
    troubleshooting easier.

3. The uses of token passing enables all devices in
    a ring topology to share the network resources
    fairly.


 Disadvantages:

1. A failure in any cable or device breaks the

    loop and can take down the entire network.

2. Data packets must pass through every computer

    therefore, this makes it slower.

3. A ring network can span a larger distance than a

    bus network, but it is more difficult to install.




Star Network Topology



*All the computers and other devices on the

  network connect to a central device, thus forming

  a star.

*Two types of devices that provide a common

  central connection point to all the other devices

  on the network are a hub and a switch

Advantages:

1. If one device fails, only that device is affected.

2. Devices can be added to or removed from

    network with little or no disruption.

3. Easy to troubleshoot and isolate problem.





Disadvantages:

1. If the hub or switch fails, the entire network will

    be inoperable.

2. Requires more cable than most of the other

    topologies.

3. More expensive because of the cost of the

    hub/switch



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