3.1.1 Network Topology Complete New

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3.0 INTERNET TECHNOLOGY

3.1 Network Basics

3.1.1 Network Topology


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LEARNING OUTCOMES

At the end of this topic, students should be able to:

1) Explain types of network topology


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Network

Network is a group of two ormore computer systems linkedtogether to exchange data and

share resources.

TOPIC 3: INTERNET TECHNOLOGY- NETWORK TOPOLOGY


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A network topology refers to the layout ofthe computers and devices in a

communications network.

It refers to both the physical and logicallayout of a network.

What Is a Topology?



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Physical Topology Logical Topology

The arrangement of acabling on a network. The path that data travelsbetween computerson a network.


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Types of network topology.

Three commonly used network topologies are:

Bus network

Star network

Ring network



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BUS NETWORKTOPOLOGY


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Bus Network Topology

A bus network consists of a single centralcable (backbone), to which all computers andother devices connect.

T-Connector

Terminator

Backbone



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The busis the physical cable that connects thecomputers 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 thattravel along the length of the cable in all directions.



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Each devices is connected to the single buscable through T-Connector.

A terminator is required at each end of the buscable to prevent the signal from bouncing backand forth on the bus cable.

T-Connector

Terminator

Backbone



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When a sending device transmits data, theaddress of the receiving device is includedwith the transmission.

If the device address does not match theintended address for the data, the deviceignores the data.

If the data does match the device address, thedata is accepted.

All devices receive the data but only the

receiving device accept them.




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Advantages:

1. Bus networks are inexpensive and easy to install,practical in a small environment such as home or

office.

2. Bus networks are reliable and easy to expand; anydevices can be attached and detached at any point

on the bus without disturbing the rest of thenetwork.

3. Failure of one computer (workstation) /device

usually does not affect the rest of the bus network.



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Disadvantages:

1. Only one computer(workstation) can transmit ata time.

2. A bus network with more than a few dozenscomputers is likely to perform poorly.

3. Because all systems on the network connect toa single cable or backbone, a break in the cablewill prevent all systems from accessing thenetwork.



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STAR NETWORKTOPOLOGY


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Star Network Topology

All the computers and other devices on thenetwork connect to a central device, thus forminga star.



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Two types of devices that provide a commoncentral connection point to all the other deviceson the network are a hub and a switch.

Hub / Switch


TOPIC 3 INTERNET TECHNOLOGY NETWORK TOPOLOGY


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The device that provides a common centralconnection point for other devices on anetwork.

All data that transfers from one device toanother passes through the hub or switch.

The hub takes a signal that comes from anydevice and passes it along to allthe other devices in the network.

Hub / Switch

Hub / Switch




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Advantages:

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

2. Devices can be added to or removed fromnetwork with little or no disruption.

3. Easy to troubleshoot and isolate problem.




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Disadvantages:

1. If the hub or switch fails, the entire network willbe inoperabled.

2. Requires more cable than most of the othertopologies.

3. More expensive because of the cost of thehub/switch.



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RING NETWORKTOPOLOGY

TOPIC 3: INTERNET TECHNOLOGY NETWORK TOPOLOGY


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Ring Network Topology

On a ring network, a cable forms a closed loop(ring) with all computers and devices arrangedalong the ring.




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Data transmitted on a ring network travels fromdevice to device around the entire ring, in onedirection (clockwise or counterclockwise)

Token passing is one method for sending dataaround a ring

Each device takes a turn sending and receiving

information through theuse of a token.




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The token along with any data is sent from thefirst device to the second device which extractsthe data addressed to it and adds any data it

wishes to send.

Then second device passes the token and data tothe third device, etc. until it comes back around to

the first device again.

Only the device with the token is allowed to senddata . All other devices must wait for the token to

come to them.



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Advantages:

1. The transmission of data is relativelysimple as packets travel in one direction only.

2. Cable faults are easily located, makingtroubleshooting easier.

3. The uses of token passing enables all devices ina ring topology to share the network resourcesfairly.




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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 computertherefore, this makes it slower.

3. A ring network can span a larger distance than abus network, but it is more difficult to install.


SUMMARY:


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DEFINITION

SUMMARY:

NETWORK TOPOLOGY

BUS

A bus network

consists of a

single central

cable (backbone),

to which all

computers and

other devices

connect.

STAR

All the computers

and other devices

on the network

connect to a

central device,

thus forming a

star.

RING

On a ring network,

a cable forms a

closed loop (ring)

with all computers

and devices

arranged

along the ring.

SUMMARY:


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ADVANTAGES

Only one computer(workstation) can transmitat a time.

A bus network with morethan a few dozens

computers is likely toperform poorly.

Because all systems on thenetwork connect to a singlecable or backbone, a breakin the cable will prevent all

systems from accessing thenetwork.

SUMMARY:

BUS NETWORK TOPOLOGY

Bus networks are inexpensiveand easy to install, practical ina small environment such as

home or office.

Bus networks are reliable andeasy to expand; any devices

can be attached and detachedat any point on the bus without

disturbing the rest of thenetwork.

Failure of one computer(workstation) /device usuallydoes not affect the rest of the

bus network.

DISADVANTAGES

SUMMARY:


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DISADVANTAGES

STAR NETWORK TOPOLOGY

If one device fails, onlythat device is affected.

Devices can be added to orremoved from network with

little or no disruption.

Easy to troubleshoot andisolate problem.

If the hub or switch fails, theentire network will be

inoperabled.

Requires more cable thanmost of the other topologies.

More expensive because ofthe cost of the hub/switch.

ADVANTAGES

SUMMARY:


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The transmission of data isRelatively simple as packetstravel in one direction only.

A failure in any cable orDevice breaks the loop and

can take down the entire

network.

Cable faults are easilylocated, making

troubleshooting easier.

The uses of token passingenables all devices in a ring

topology to share theNetwork resources fairly.

Data packets must passthrough every computertherefore, this makes it

slower.

A ring network can span alarger distance than a bus

network, but it is moreDifficult to install.

RING NETWORK TOPOLOGY

DISADVANTAGESADVANTAGES


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1) Which of the following statements describe aboutnetwork topology correctly ?

A. Devices attached or detached at any point on the

network.

B. The failure of device on the network.

C. Refers to the configuration of cables, computers

and other peripherals.

D. All of the above.

EXERCISE:


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2) On a __________, all of the computers and deviceson the network connect to a central device.

A. Bus network.

B. Ring network.

C. Star network.

D. All of above.

EXERCISE:


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3) On a star network, the central device that providesa common connection point for nodes on theNetwork is called the ____________.

A. Hub.

B. Personal computer.

C. Printer.

D. File server.

EXERCISE:


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4) On a bus network, if one node fails ________.

A. Only that node is affected.

B. Only the nodes before that node are affected.

C. Only the nodes after that node are affected.

D. All the nodes are affected.

EXERCISE:


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The transmission of data is relatively simpleas packets travel in one direction only.

5) The statement above is correctly refer tothe _________________.

A. Bus network.

B. Ring network.

C. Star network.

D. All of the above.

EXERCISE:

3.1.1 Network Topology Complete New

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