Network

1. Exercise # 1
Introduction to Computer Networks
Objectives / Statement Purpose:
To study about some basic concepts of Computer Networks
Describe the Network Devices
Explain how devices use in the internetwork
Types of Network
Internet in detail
Activity Outcomes:
The student should know the Infrastructure of Internet
The students should know how networks helping us in daily life
The student should know the network devices in detail with their applications
Instructions:
The purpose of the networking guidelines are as follows:
To assist students in understanding the benefits of networking.
.
To assist students in planning the next stage of network development
To provide standard networking ‘models’ and best practice to students
that will assist students in their network planning.

2. A network is a set of devices (often referred to as nodes)
connected by communication links. A node can be a
computer, printer, or any other device capable of sending
and/or receiving data generated by other nodes on the
network.
Distribued Procession
Network Criteria
Physical Structures
Network Models
Interconnection of Networks: Internetwork
1- Distributed Processing:- A task is divided among
multiple computers.
2- Network Criteria: A network must be able to meet a
certain number of criteria. The most important of these
are performance, reliability and security.

3. Interconnection of Networks: Internetwork
Distributed Processing:- A task is divided among multiple computers.
Network Criteria: A network must be able to meet a certain number
of criteria. The most important of these are performance, reliability
and security.
1.Performance: - Performance is measured in many ways including
transit time and response time. Transit time is the amount of time
required for a message to travel from one device to another. Response
time is the elapsed time between an query and a response
ii. Reliability: - Reliability is measured by the frequency of failure,
the time it takes a link to recover from a failure.
iii. Security:- Network security issues include protecting data from
unauthorized access.

4. . Physical Structures
Types of connections: A network is two or more devices
connected through links. A link is a communications
pathway that transfers data from one device to another
a) Point- to-point: - A point to point connection
provides a dedicated link between two device.
b) Multipoint:-A multipoint connection is one in which
more than two specific devices share a single link.

6. Physical topology:- the term physical topology refers to the way in
which a network is laid out physically
Mesh:- In a mesh topology every device has a dedicated point-to-
point link to every other device
Star topology:-In a star topology each device has a dedicated
point-to-point link only to a central controller, usually called a hub.
Bus topology:- A bus topology, on the other hand, is multipoint.
One long cable acts as a backbone to link all the devices in a
network.
Ring topology:-In a ring topology, each device has a dedicated
point-to-point connection with only the two devices on either side
of it. A signal is passed along the ring in one direction, from devices
to device, until it reaches its destination.
Hybrid topology: - A network can be hybrid. For example, we can
have a main star topology with each branch connecting several
stations in a bus topology.

7. Categories of topology

8. A fully connected mesh topology (five devices)

9. A star topology connecting four stations

10. A bus topology connecting three stations

11. A ring topology connecting six stations

12. A hybrid topology: a star backbone with three bus networks

13. 4. Network Models: - Standards are needed so that
these heterogeneous networks can communicate with
one another. The two best known standards are the OSI
model and the internet model.
5. Categories of networks
•LAN (local Area Network) is usually privately owned
and links the devices in a single office, building or
campus.
•WAN (Wide area Network) provides long-distance
transmission of data, image, audio and video information
over large geographic areas that may comprise a
country a, a continent or even the whole world.
•MAN (Metropolitan Area Network) is a network with the
size between a Lan and a WAN. It normally covers the
area inside a town or a city.

14. 6. Interconnection of Networks: Internetwork:-When
two or more networks are connected, they become an
internetwork or internet.
An isolated LAN connecting 12 computers to a hub
in a closet