WASEEM ALI

2. COMPUTER
NETWORKS

3. GROUP 6
MEMBERS
 Saba Irshad (Models & Topologies)
 Hassan (MethodsTypes)
 Ammara Ashraf (Internetworking Tools)
 Swaira Shabbir (OSI Model)
 Muneeb (Wireless Networks)
 Nimra Sattar (Communication Protocol)

4. COMPUTER NETWORK , NETWORK MODELS
AND TOPOLOGIES

5. COMPUTER NETWORK
 Computer network connects
computers in a manner to
enable meaningful transmission
and exchange of data between
them.
 In computer network we can
share information, share
resources (hardware, software).
 Computer network is also called
Information network.
For Example: Internet

6. HISTORY OF COMPUTER NETWORK
 The first-ever Computer-to-Computer link
was established on ARPANET (Advance
Research Project Agency Network) , the
precursor to the Internet, on October 29,
1969.
 The message on the ARPANET was sent by
UCLA student programmer Charles S Kline.

7. NETWORK TOPOLOGIES
 A Network
Topology
refers to the
way in which
nodes are
connected in
network.

8. BUS TOPOLOGY
 In Bus Topology, all
nodes are connected
to a single
communication line.

Advantages
 Reduce number of
physical line.
 Failure of node does
not effect the network
 .
Disadvantages
 Communication line
fails, the whole
network fails.

9. STAR TOPOLOGY
 In a star topology all
computers or nodes are
directly connected to a
central device called hub or
switch.
Advantages
 New nodes can easily added
and removed to and from the
central device.
 If any node fails, other nodes
are not affected
 .
Disadvantages
 If the central device fails the
whole network fails.

10. RING TOPOLOGY
 In a ring topology, each
computer is connected to
the next computer and the
last computer is
connected to the first.

Advantages
 It is less expensive than
star topology.
 All computers has equal
access to network.
Disadvantages
 If one node fails, the
entire network stops
functioning.
 Adding and removing
nodes affects the network

11. TREE TOPOLOGY
 Tree topology has
combined features of
bus and star
topologies. Typically
to form a tree
network, multiple star
topologies are
combined together
through Central cable
or bus.

12. MESH TOPOLOGY OR COMPLETELY
CONNECTED NETWORK
 In mesh topology, each
node has directly link,
with all other nodes.
Advantages
 It provides multiple routes
for date communication.
 It ensures data privacy.
 Communication is very
fast.
Disadvantages
 It is very expensive.

13. HYBRID NETWORK
 Hybrid network
combines two or more
networks. A hybrid
topology is a type of
network topology that
uses two or more other
network topologies
including bus
topology, mesh
topology, ring
topology, star topology,
and tree topology.

14. METHODSTYPES

15. TYPES OF NETWORK
 Depending upon the geo graphical area covered by a
network, it is classified as:
 Personal Area Network (PAN)
 Metropolitan Area Network (MAN)
 Local Area Network (LAN)
 Wide Area Network (WAN)

16. PERSONAL AREA NETWORK (PAN)
 A Personal Area Network is a computer network used for communication
among computer devices, including telephones, tablets, and personal digital
assistants.
 The reach of a PAN is typically a few meters.
 Personal area network may be wired with computer buses such as USB and
FireWire.
 A Wireless Personal Area Network can also be made possible with wireless
network technologies such as, Bluetooth, Wireless USB.

17. ADVANTAGES & DISADVANTAGES OF
PAN
Advantages:
 The PAN is a personal network of one or two person so there is no risk of
any leak of data.
 They are quick and easy.
 PAN usually need less technical skill.
 WPAN devices are easy portable.
Disadvantages:
 PAN have limited range.
 Devices are not compatible with each other.
 Devices with inbuilt WPANs are more expensive.

18. METROPOLITAN AREA NETWORK
(MAN)
 MAN is a network system that covers area of a single city.
 It covers a smaller geographical area than a WAN.
 Mobile phones systems often use MAN.
 In this type of network, fiber optics cables are used as communication
media.
 It is very high speed network.

19. ADVANTAGES &
DISADVANTAGES OF MAN
Advantages:
 It provides a good back bone for a large network and provides greater
access to WANs
 The dual bus used in MAN helps the transmission of data in both direction.
 A MAN usually encompasses several blocks of a city or an entire city.
Disadvantages:
 More cables required for a MAN connection from one place to another.
 It is difficult to make the system secure from hackers and industrial
spying.

20.  A Local Area Network is a group of computers and associated devices
that share a common communications line or wireless link.
 The computers used in LAN also require network interface card.
 They are connected to each other in a limited area. Typically, this area
is up to ONE KM.
 LAN is also known as Local Net.
LOCAL AREA NETWORK (LAN)

21. ADVANTAGES & DISADVANTAGES OF
LAN
ADVANTAGES:
 The resources can be shared among different users.
 All data is stored on the central server. So it becomes very easy to
manage the data.
 LAN is not very expensive.
 Data transmission in a LAN is very high.
DISADVANTAGES:
 If central server is infected by virus, then the important data stored on
server may be corrupted and the entire network may also be effected.
 All nodes depends on the central computer ( or Hub ), if any component
of server fails, then entire network will stop working.

22. WIDE AREA NETWORK (WAN)
 A Wide Area Network is a type of computer network
that covers a large area such as different cities of
country or different countries of the world.
 Computers and other devices in a WAN are often
connected through telephone lines.
 The internet is the world’s largest WAN.
 Many large organizations make use of WAN as
enterprise network.

23. ADVANTAGES & DISADVANTAGES
OF WAN
Advantages:
 WAN covers a large geographical area.
 Message may be shared and communicated all over the world.
 The software can be shared between different users all over the
world.
 The data of an organization is stored in a single location. Everyone
on the network can use the same data.
Disadvantages:
 WAN becomes expensive to install. WANs are very costly.
 It is very expensive to run the WAN.
 WAN is very slow for data transmission.
 If the server fails, the entire network is effected.

24. INTERNETWORKING TOOLS

25. INTERNETWORKING TOOLS

26. INTERNETWORKING TOOLS
 Interconnecting two or
more networks to form
a single network is
called Internetworking
and the resulting
network is called
internetwork.
 Internetworking may
or may not be differ in
protocol and topology.
 The goal of
Internetworking is to
Interconnect different
physical networks and
to hide their details,
enabling the
internetwork to
function as a single
coordinated unit.

27. BRIDGE
Bridge is used to
connect similar
networks segments.
It may or may not
use the same
protocols at physical
and data link layers.
 For Example, a
bridge can connect
two networks, one of
which uses fiber-
optic communication
medium and the
other uses coaxial
cable.
 However, networks
must use the same
high level protocols
(e. g, TCP/IP) to

28. ROUTER
 Router is used to connect
two or more different or
similar networks.
 Router is smarter than
bridge because they not
only copy a data from one
network segment to another
but also choose the best
route for the data by using
information in a routing
table.

29. GATEWAY
 Gateway is used to
connect two or more
different types of
networks.
 It is the most
sophisticated(great)
Internetworking tool.
Sometimes gateway
perform the routing
information
 Gateway convert data
packet from one format
to another format.

30. DIFFERENCE BETWEEN ROUTER AND
GATEWAY
 Route traffic from one network
to another
 Supports dynamic routing.
 Work on layer 3 &layer 4 of
OSI Model.
 Router forwards packet of data
from one network to another.
Router Gateway
 Translate data from one
format to another format.
 Doesn't support dynamic
routing.
 Work up to layer 3 to 5 of
OSI Model.
 Gateway is a device that
convert one protocol format
to another.

31. OSI MODEL

32. HISTORY OF OSI MODEL
 In 1979 ISO & CCITT (two international standards
organization) developed a document that defined
similar networking models.
 In 1983, these two documents were merged to form a
standard called “The Basic Reference Model for
Open System Interconnection". It is simply called OSI
Model.
 OSI Model had two major components, an abstract
model, called seven layer model & a set of specific
protocols.
 It was published in 1984 by ISO as standard ISO7498
& CCITT as standard X200.

33. CHARLES BACHMAN
The concept of seven layer model was provided by
the work of Charles Bachman at Honeywell
Information Services.

34. OSI MODEL
 OSI stands for Open System
Interconnection.
 OSI is the most widely accepted model for
network communication.
 OSI model provides a useful structure for
defining and describing various process of
networking.
 It organizes the communication into seven
layers.

35. OSI MODEL

36. WIRELESS NETWORKS

37. WIRELESS NETWORKS
 Wireless network is any
type of computer network
that uses wireless
transmission media to
communicate between
nodes.
 Wireless networks are
computer networks that are
not connected by cables of
any kind.
 For Example: Cellular
Phones

38. TYPES OF WIRELESS COMPUTING SYSTEMS
 Wireless computing systems
are of two types:
1. Fixed wireless systems
2. mobile wireless systems

39. 1: FIXED WIRELESS SYSTEMS
 These wireless computing systems support
little or no mobility of their computing equipment.
2: Mobile Wireless Systems
 These wireless computing systems support
mobility of users and allow mobile users to
access
at any time or place. Resulting computing is
called mobile computing or nomadic
computing.

40. ISSUES IN WIRELESS COMPUTING SYSTEMS
Computing systems faces many challenges. The
important ones among them are:
1. Lower bandwidth
2. Variable bandwidth
3. Higher error rate
4. Increased security concern
5. Dynamically changing network
6. Lost or degraded connection
7. Support for routing and location management
function
8. Limited power

41. WIRELESS TECHNOLOGIES
 Some wireless technologies are:
 2G and 3G Technologies
 Wireless LAN (WLAN)
 WiMAX
 Wireless Local Loop(WLLs)

42. 2G AND 3G TECHNOLOGIES
 2G was digital, circuit based and narrowband
but suitable for voice and limited data
communication.
 3G is suitable for online multimedia, data
applications and voice.
Wireless LAN(WLAN)
 A Wireless Local Area Network (WLAN) is a
LAN that enables wireless communication
among equipment which are the part of LAN.

43. WIMAX
 WiMAX is a technology based on IEEE 802.16
for providing wireless communication in WMANs
Wireless Local Loops(WLLs)
 Wireless Local Loop technology supports fixed
wireless systems and provides several MHz of
bandwidth which offer high-speed internet.

44. COMMUNICATION PROTOCOL

45. COMMUNICATION PROTOCOL
 A set of rules for exchanging
data between computers
connected to a network is
called NETWORK
PROTOCOL. It provide a
method for efficient exchange
of data between
senderreceiver , and for
proper interpretation of
controls and data transmitted
as raw bits and bytes.

46. RULES OF COMMUNICATION
PROTOCOL
1. Data sequencing
2. Data routing
3. Data formatting
4. Flow control
5. Error control
6. Procedure & order of transmission
7. Connection establishment
8. Data security
9. Log information

47. CONCEPT OF LAYERED PROTOCOL IN
NETWORK DESIGN
 Modern computer networks have modular
design for easy and efficient handling of
system. They consist of several modules,
which are grouped into layers logically. Each
layer has its own set of protocols. A
particular layer of one machine
communicates only with corresponding layer
of another machine by using protocols of
this layer.

48. REASON FOR USING LAYERED
PROTOCOL
1. Protocol of network are complex
2. Layered Protocol provides well-defined
interface between layers
3. Layering of protocols also allows interaction
between functionally paired layers

49. NETWORK INTERFACE CARD (NIC)
 NIC is a hardware device that connects a
computer to a network, both functionally and
physically. It is Printed Circuit Board(PCB),
which connects to one of the expansion slot of
computer, and provides a port for attaching a
network cable.NIC connects directly to a
computer’s IO bus. NIC ‘s ROM has the
network’s physical-layer communication
protocol. There are different NICs for different
netwrks. NIC is also called Network Card.