2. 3.0
Internet Technology
3.1 3.2 3.3 3.5
Network The Internet Internet Netiquette
Basic Services
3.2.1 3.2.2
Overview the World Wide Web
3.1.1 internet
Network Topology 3.2.2.1
3.2.1.1 Web Browser 3.4
3.1.2 Evolution of the Types of
Classification of internet 3.2.2.3
network Web page
Websites
3.2.1.2 navigation
The internet
connection 3.2.2.4
Information
3.2.1.3 searching
Internet Service
Provider
3.2.1.4
The Internet
Address
3.
4. LEARNING OUTCOMES
At the end of this topic, students should
be able to:
1) Explain types of network topology
5. What Is a Network?
A network is a collection of
computers and devices connected
together via communications devices
and transmission media
Shelly Cashman
6. What Is a Network Topology?
A network topology refers to the layout
of the computers and devices in a
communications network.
Shelly Cashman
11. Bus Network Topology
A bus network consists of a single central
cable (backbone), to which all computers and
other nodes connect.
Backbone
12. Bus Network Topology
The bus is the physical cable that connects the computers
and other nodes.
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 all directions.
13. Bus Network Topology
Each nodes is connected to the single bus
T-Connector
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.
14. Bus Network Topology
When a sending device transmits data, the address of the
receiving device is included with the transmission.
If the device address does not match the intended address for
the data, the device ignores the data.
If the data does match the device address, the data is
accepted.
All devices receive the data but only the receiving device
accept them.
15. Bus Network Topology
Advantages:
1. Inexpensive and easy to install.
2. Computers and other nodes can be attached
and detached at any point on the bus without
disturbing the rest of the network.
3. Failure of one node usually does not affect the
rest of the bus network.
16. Bus Network Topology
Disadvantages:
1. 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.
2. It is difficult to identify the problem if the entire network
shut down.
18. Star Network Topology
All the computers and other nodes on the
network connect to a central device, thus
forming a star.
19. Star Network Topology
Two types of nodes that provide a common
central connection point to all the other nodes
on the network are a hub and a switch.
Hub / Switch
20. Star Network Topology
Hub / Switch
The device that provides a common central
connection point for other devices on a network.
All data that transfers from one node to another passes
through the hub or switch.
The hub takes a signal that comes from any node and passes
it along to all the other nodes in the network.
21. Star Network Topology
Advantages:
1. If one node fails, only that node is affected.
2. Nodes can be added to or removed from
network with little or no disruption.
3. Easy to troubleshoot and isolate problem.
22. Star Network Topology
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.
24. Ring Network Topology
On a ring network, a cable forms a closed loop
( ring ) with all computers and devices arranged
along the ring.
25. Ring Network Topology
Data transmitted on a ring network travels from node to
node around the entire ring, in one direction
Token passing is one method for sending data around a ring
Each node takes a turn sending and receiving information
through the use of a token.
26. Ring Network Topology
The token along with any data is sent from the first device to
the second device which extracts the data addressed to it
and adds any data it wishes to send.
Then second device passes the token and data to the third
device, etc. until it comes back around to the first device again.
Only the device with the token is allowed to send data.
All other devices must wait for the token to come to them.
28. Ring Network Topology
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 nodes in
a ring topology to share the network resources
fairly.
29. Ring Network Topology
Disadvantages:
1. A failure in any cable or node 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.
30. SUMMARY:
BUS NETWORK TOPOLOGY
DEFINITION ADVANTAGES DISADVANTAGES
A bus network The break in the
consists of a main cable(backbone)
single central Inexpensive and
easy to install. will prevent all systems
cable (backbone), from accessing the
to which all network.
computers and
other nodes
connect. Other nodes can be It is difficult to
attached or detached identify the problem
without disturbing if the entire network
the network. Shut down.
Failure of one node
usually does not
affect the rest
of the network.
31. SUMMARY:
STAR NETWORK TOPOLOGY
DEFINITION ADVANTAGES DISADVANTAGES
All the computers If the hub or switch
and other nodes If one node fails,
fails, the entire
on the network only that node
network will be
connect to a is affected.
inoperabled.
central device,
thus forming a
star.
Nodes can be added
Requires more cables
or removed from
than most of the
network with no
other topologies.
disruption.
Easy to More expensive
troubleshoot and because of the
isolate problem. cost of hub/switch.
32. SUMMARY:
RING NETWORK TOPOLOGY
DEFINITION ADVANTAGES DISADVANTAGES
On a ring network, A failure in any cable
Transmission of data or nodes breaks the
a cable forms a is simple as packets
closed loop (ring) loop and can take
travel in one down entire
with all computers direction only.
and nodes network.
arranged
along the ring.
Cabel faults are easily Data packets must
located, making pass through every
troubleshooting computer, thus make
easier. it slower.
All nodes in ring More difficult to
topolgy share the install than a
network resources bus network.
fairly.
33. EXERCISE:
1) Which of the following statements describe about
network topology correctly ?
A. Nodes 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.
34. EXERCISE:
2) On a __________, all of the computers and nodes
on the network connect to a central device.
A. Bus network.
B. Ring network.
C. Star network.
D. All of above.
35. EXERCISE:
3) On a star network, the central nodes that provides
a common connection point for nodes on the
Network is called the ____________.
A. Hub.
B. Personal computer.
C. Printer.
D. File server.
36. EXERCISE:
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.
37. EXERCISE:
The transmission of data is relatively simple
as packets travel in one direction only.
5) The statement above is correctly refer to
the _________________.
A. Bus network.
B. Ring network.
C. Star network.
D. All of the above.
Editor's Notes
Machine 1 wants to send some data to machine 4, so it first has to capture the free Token. It then writes its data and the recipient's address onto the Token (represented by the yellow flashing screen). The packet of data is then sent to machine 2 who reads the address, realizes it is not its own, so passes it on to machine 3. Machine 3 does the same and passes the Token on to machine 4. This time it is the correct address and so number 4 reads the message (represented by the yellow flashing screen). It cannot, however, release a Token on to the ring, it must first send the message back to number 1 with an acknowledgement to say that it has received the data (represented by the purple flashing screen). The receipt is then sent to machine 5 who checks the address, realizes that it is not its own and so forwards it on to the next machine in the ring, number 6. Machine 6 does the same and forwards the data to number 1, who sent the original message. Machine 1 recognizes the address, reads the acknowledgement from number 4 (represented by the purple flashing screen) and then releases the free Token back on to the ring ready for the next machine to use.
