IT infrastructure and network technologies for Semi Final

IT Infrastructure and Network
Technologies
Semi Final
Instructor: Mark John P. Lado

Objectives
Have the basic understanding of network
topology.
Determine the function of different topologies.

Network Topology
Network Topology is the schematic description
of a network arrangement, connecting various
nodes (sender and receiver) through lines of
connection.

BUS Topology
Bus topology is a network type in which every
computer and network device is connected to
single cable. When it has exactly two endpoints,
then it is called Linear Bus topology.

Features of Bus Topology
It transmits data only in one direction.
Every device is connected to a single cable

Advantages of Bus Topology
It is cost effective.
Cable required is least compared to other network
topology.
Used in small networks.
It is easy to understand.
Easy to expand joining two cables together.

Disadvantages of Bus Topology
Cables fails then whole network fails.
If network traffic is heavy or nodes are more the
performance of the network decreases.
Cable has a limited length.
It is slower than the ring topology.

RING Topology
It is called ring topology because it forms a ring as
each computer is connected to another computer,
with the last one connected to the first. Exactly
two neighbors for each device.

Features of Ring Topology
A number of repeaters are used for Ring topology
with large number of nodes, because if someone
wants to send some data to the last node in the
ring topology with 100 nodes, then the data will
have to pass through 99 nodes to reach the 100th
node. Hence to prevent data loss repeaters are
used in the network.

The transmission is unidirectional, but it can be
made bidirectional by having 2 connections
between each Network Node, it is called Dual
Ring Topology.

In Dual Ring Topology, two ring networks are
formed, and data flow is in opposite direction in
them. Also, if one ring fails, the second ring can
act as a backup, to keep the network up.

Data is transferred in a sequential manner that is
bit by bit. Data transmitted, has to pass through
each node of the network, till the destination node.

Advantages of Ring Topology
Transmitting network is not affected by high traffic
or by adding more nodes, as only the nodes
having tokens can transmit data.
Cheap to install and expand

Disadvantages of Ring Topology
Troubleshooting is difficult in ring topology.
Adding or deleting the computers disturbs the
network activity.
Failure of one computer disturbs the whole
network.

Self Check
On a ½ cross wise clean paper.
Distinguish the difference between Bus Topology
and Ring Topology.

STAR Topology
In this type of topology all the computers are
connected to a single hub through a cable. This
hub is the central node and all others nodes are
connected to the central node.

Features of Star Topology
Every node has its own dedicated connection to
the hub.
Hub acts as a repeater for data flow.
Can be used with twisted pair, Optical Fiber or
coaxial cable.

Advantages of Star Topology
Fast performance with few nodes and low network
traffic.
Hub can be upgraded easily.
Easy to troubleshoot.
Easy to setup and modify.
Only that node is affected which has failed, rest of the
nodes can work smoothly.

Disadvantages of Star
Topology
Cost of installation is high.
Expensive to use.
If the hub fails then the whole network is stopped
because all the nodes depend on the hub.
Performance is based on the hub that is it depends on its
capacity

MESH Topology
It is a point-to-point connection to other nodes or
devices. All the network nodes are connected to
each other.

MESH Topology
There are two techniques to transmit data over the
Mesh topology, they are:
1. Routing
2. Flooding

MESH Topology: Routing
In routing, the nodes have a routing logic, as per
the network requirements. Like routing logic to
direct the data to reach the destination using the
shortest distance. Or, routing logic which has
information about the broken links, and it avoids
those node etc. We can even have routing logic,
to re-configure the failed nodes.

MESH Topology: Flooding
In flooding, the same data is transmitted to all the
network nodes, hence no routing logic is required.
The network is robust, and the its very unlikely to
lose the data. But it leads to unwanted load over
the network.

Types of Mesh Topology
Partial Mesh Topology : In this topology some of
the systems are connected in the same fashion as
mesh topology but some devices are only
connected to two or three devices.

Types of Mesh Topology
Full Mesh Topology : Each and every nodes or
devices are connected to each other.

Features of Mesh Topology
Fully connected.
Robust.
Not flexible.

Advantages of Mesh Topology
Each connection can carry its own data load.
It is robust.
Fault is diagnosed easily.
Provides security and privacy.

Disadvantages of Mesh
Topology
Installation and configuration is difficult.
Cabling cost is more.
Bulk wiring is required.

Self Check – ½ crosswise
1. List down the 3 features of Star Topology.
2. Give the 3 features of Mesh Topology.
3. Give at least one advantage of Star Topology.
4. What are two techniques to transmit data over
the Mesh topology?
5. Give at least one advantages of Mesh Topology.

Check point
You have now an idea of what is topology
specifically in the bus, ring, star, and mesh
topology. Before we will proceed to the advance
and more wide-ranging topologies lets have a
quick recap! Try to picture out all of those
topologies we discussed, the bus, ring, star, and
mesh topology

Self Check
On a 1 whole sheet of paper.
Draw a diagram of the bus, ring, star, and mesh
topology and give a brief discussion in each
diagram.

TREE Topology
It has a root node and all other nodes are
connected to it forming a hierarchy. It is also
called hierarchical topology. It should at least have
three levels to the hierarchy.

Features of Tree Topology
Ideal if workstations are located in groups.
Used in Wide Area Network.

Advantages of Tree Topology
Extension of bus and star topologies.
Expansion of nodes is possible and easy.
Easily managed and maintained.
Error detection is easily done.

HYBRID Topology
It is two different types of topologies which is a
mixture of two or more topologies. For example if
in an office in one department ring topology is
used and in another star topology is used,
connecting these topologies will result in Hybrid
Topology (ring topology and star topology).

Features of Hybrid Topology
It is a combination of two or topologies
Inherits the advantages and disadvantages of the
topologies included

Advantages of Hybrid Topology
Reliable as Error detecting and trouble shooting is
easy.
Effective.
Scalable as size can be increased easily.
Flexible.

Disadvantages of Hybrid Topology
Complex in design.
Costly.

Self Check – 1 whole clean paper
1. Draw the schematic diagram of a HYBRID
Topology and give a brief discussion .
2. Draw an illustration of TREE Topology and
give a concise details.

Summing up
What is the importance of topology?

Summing up
Draw the following on the board.
Bus Topology
Ring Topology
Star Topology

Summing up
Draw the following on the board.
Mesh Topology
Tree Topology
Hybrid Topology

Transmission Modes
in
Computer Networks

Objectives
Engage in different types of transmission modes.
Determine the roles of Transmission Modes in
Computer Networks.

Transmission Modes in
Computer Networks
Transmission mode refers to the mechanism of
transferring of data between two devices
connected over a network. It is also
called Communication Mode. These modes
direct the direction of flow of information.

Computer Networks
There are three types of transmission modes.
Simplex Mode
Half duplex Mode
Full duplex Mode

Computer Networks

SIMPLEX Mode
In this type of transmission mode, data can be
sent only in one direction i.e. communication is
unidirectional. We cannot send a message back to
the sender. Unidirectional communication is done
in Simplex Systems where we just need to send a
command/signal, and do not expect any response
back.

SIMPLEX Mode
Examples of simplex Mode are loudspeakers,
television broadcasting, television and remote,
keyboard and monitor etc.

HALF DUPLEX Mode
Half-duplex data transmission means that data
can be transmitted in both directions on a signal
carrier, but not at the same time.

HALF DUPLEX Mode
For example, on a local area network using a
technology that has half-duplex transmission, one
workstation can send data on the line and then
immediately receive data on the line from the
same direction in which data was just transmitted.

HALF DUPLEX Mode
Hence half-duplex transmission implies a
bidirectional line (one that can carry data in both
directions) but data can be sent in only one
direction at a time.

HALF DUPLEX Mode
Example of half duplex is a walkie- talkie in which
message is sent one at a time but messages are
sent in both the directions.

FULL DUPLEX Mode
In full duplex system we can send data in both the
directions as it is bidirectional at the same time in
other words, data can be sent in both directions
simultaneously.

FULL DUPLEX Mode
Example of Full Duplex is a Telephone Network in
which there is communication between two
persons by a telephone line, using which both can
talk and listen at the same time.

FULL DUPLEX Mode
In full duplex system there can be two lines one
for sending the data and the other for receiving
data.

Self Check
On a ½ crosswise clean paper.
Answer the following.
What is Transmission Modes?
What are the three types of transmission modes?

Self Check
Draw the illustration
SIMPLEX Mode
HALF DUPLEX Mode
FULL DUPLEX Mode

IT infrastructure and network technologies for Semi Final

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