This document provides an overview of computer networks. It discusses network diagrams, classifications of networks by range including LAN, WAN, PAN and MAN. Common network topologies such as bus, star, ring and mesh are described. The OSI and TCP/IP models are explained. Common network devices, switching technologies, and transmission media are defined. Signal types including analog and digital are also summarized.

1. COMPUTER NETWORKS
Assigned by: Sir Ayaz Keerio Submitted b
Kiran Buriro
2K17/MCS/O7

2. PRESENTATION GOALS
What is Network
Network Diagram
Classification of Network
Network Topologies
OSI Reference Model
TCP/IP Model
Agenda of TCP/IP Model
Protocol Architecture
Transmission Media
Guided Media
Unguided Media
 Network devices
Switching Technologies
General Network Design Process
Classification of Networks by
range
Protocols
Communication
Communication Model
Signals
Analog
Digital

3. The Network Diagram

4. COMMUNICATION MODEL

5. SCALE
• Local Area
Network(LAN)
• Wide Area
Network(WAN)
• Metropolitan Area
Network
• Personal Area
Network()PAN
CONNECTION
METHODS
• Optical fiber
• Ethernet
• Wireless LAN
• Power Line
Communication
FUNCTIONAL
RELATIONSHIP
• Active Networking
• Client-server
• Peer-to-peer
NETWORK
TOPOLOGY
• Bus Network
• Star Network
• Ring Network
• Mesh Network

6. Classification of Network by Range
LAN (Local Area Network)
WAN (Wide Area Network)
PAN (Personal Area Network)
MAN (Metropolitan Area Network)

7. Local Area Network(LAN)
Ethernet
LAN in your office
WLAN in your home

8. Wide Area Network(WAN)
CHICGO
PAKISTAN
NEW YORK

9. Metropolitan Area Network(MAN)
Islamabad
Hyderabad
Karachi

10. Personal Area Network(PAN)
Room 1
HOME
Room 2

11. Open System Interconnection
(OSI) Reference Model
Physical
Datalink
Network
Transport
SessionPresentation
Application
OSI (Open Systems
Interconnection) Reference
model deals with connecting
open systems (systems that
are open for communication
with other systems
Logical connection to be
established on an end-
user’s
Ensures that the data
units are delivered error
free.
Implements routing of
frames (packets)
through the network.
Data link layer Breaks
the outgoing data into
frames and reassemble
the received frames.
Provides physical interface
for transmission of
information.
Application layer
interacts with
application programs and
management functions to
support distributed
applications.
Presentation layer
defines the format and
data encryption
(cryptography).

12. APPLICATION LAYER
PRESENTATION LAYER
SESSION LAYER
TRANSPORT LAYER
NETWORK LAYER
DATA LINK LAYER
PHYSICAL LAYER
OSI WORKING Mechanism
APPLICATION LAYER
PRESENTATION LAYER
SESSION LAYER
TRANSPORT LAYER
NETWORK LAYER
DATA LINK LAYER
DATA
DATA
DATA
DATA
DATA
DATA
DATA PHYSICAL LAYERDATA
DATA
DATA
DATA
DATA
DATA
DATA

13. TCP/IP PROTOCOL
Application
Transport
Network
Datalink
Physical
Application programs
using the network
Management of end-to-end
message transmission,error
detection and error
correction
Handling of datagrams
: routing and
congestion
Physical Media Management of cost effective
and reliable data delivery,access
to physical networks
The current Internet is based
on a TCP/IP reference model.
TCP and IP are two protocols of
this model. TCP stands for
Transmission Control Protocol and IP
stands for Internet Protocol.

14. APPLICATION LAYER
TRANSPOR LAYER
NETWORK LAYER
DATA LINK LAYER
PHYSICAL LAYER
TCP/IPWORK
Message Received
APPLICATION LAYER
TRANSPOR LAYER
NETWORK LAYER
DATA LINK LAYER
PHYSICAL LAYER

15. In general ,the network design problems consists of the following 3 general
elements:
Environmental given: Includes the locations of hosts, servers,
terminals and other nodes
Performance constraints: Consists of network reliability, traffic
throughput and host/client computer speeds
Internetworking variables: Includes the network topology, line
capacities, and packet flow assignments

16. Access needs and costs
Select topologies and technologies to
satisfy needs
Model network workload
Simulate behaviour under expected
load
Perform sensitivity tests
Rework design as needed
General Network Design Process

17. Network topologies
describe the ways in which
the elements of a
network are mapped.
They describe the physical
and logical arrangement of
the network nodes.
The physical topology of a
network refers to the
configuration of cables,
computers, and other
peripherals.
NETWORK TOPOLOGIES

18. BUS TOPOLOGY

19. STAR TOPOLOGY

20. RING TOPOLOGY

21. MESH TOPOLOGY

22. TREE TOPOLOGY

23. HYBRID TOPOLOGY

24. Agenda of TCP/IP Model
ADDRESSING
CONNECTION
ESTABLISHMEN
T
CONNECTION
RELEASE
FLOW
CONTROL
ERROR
HANDLING
INTERFACE
AND STATE
MACHINE
The “three-way handshake"
is the procedure used to
establish a connection.
This procedure normally is
initiated by one TCP and
responded to by another
TCP.
Release can be
asymmetric(one sided,
where data may loss ) or
symmetric (both sides
agreed).
A network address is an identifier for
a node or network interface of
a telecommunications network.
Network addresses are designed to be
unique across the network, although
some networks allow for local, private
addresses or locally administered
addresses that may not be unique.
Flow Control is one important
design issue for the Data Link
Layer that controls the flow
of data between sender and
receiver.
Error control is the
process of detecting and
correcting both the bit
level and packet level
errors.
a state machine is any device that stores
the status of something at a given time
and can operate on input to change the
status and/or cause an action or output to
take place for any given change.

25. Protocol Architecture Of
OSI & TCP/IP
Host-to-Network
Network Access
Layer Ethernet Token ring ATMFrame
Internet Protocol IP
Internet layer
Transmission
Control
Protocol (TCP)
User Datagram
Protocol(UDP)
Transport layer
DNS SNMP
RIP
Application layer FTP
TELNE
T
SMPT
HTTP

26. Protocols
TCP
UDP
SMTP

30. Transmission Medium

31. COAXIAL CABLE
Outer jacket
Foil Shield
Braided Shield
Center
Conductor

32. TWISTED PAIR
Crimping tool
JacketFoil Shield
Drain wire
Insulated twisted
pair conductors
Outer Jacket
Rip Cord
Insulation
Conductor

33. FIBER OPTICS
Optical fiber
Outer Jacket
Protective Coating
Fiber Coating
Central Strength element
Optical signals

34. UNGUIDED MEDIA(Wi-Fi)
Microwaves
Satellite
Radio waves

35. UNGUIDED MEDIA(Wi-Fi)

36. UNGUIDED MEDIA(Satellite)

37. UNGUIDED MEDIA(Infrared)

38. NETWORK DEVICES
Networking hardware includes all computers, peripherals,
interface cards and other equipment needed to perform data-
processing and communications within the network.
Networks Devices
includes:
Network Interface
Card
Hub
Repeater
Bridge
Switch
Router
Gateway
SWITCH
ROUTER
BRIDGE
REPEATERS
FILE SEREVERS
WORKSTATIONS

39. Network Interface Card(NIC)
A network interface card is a piece of
computer hardware designed to allow
computers to communicate over a
computer network.
The computers that are part of Ethernet
have to install a special card called
Ethernet Card.
An Ethernet supports three types of
connections:
RJ-45 connection, if it is designed
for twisted pair
BNC Connector, if it is designed for
coaxial cable
AUI connector

40. HUB
A Hub is a hardware device used to
connect several computers together. A hub
contains multiple ports.
FUNCTIONING OF A HUB:
Hubs forward any data packets – including
e-mail, word documents, spreadsheets,
graphics- they receive over one port to all
of the remaining ports. All users connected
to a single hub are in the same segment.
ACTIVE HUB: Electrically amplifies the
signal as it moves from one connected
device to the other.
PASSIVE HUB: Allows the signal to pass
from one computer to another without any
change.
INTELLIGENT HUB:I ntelligent hub include
additional features that enables an
administrator to monitor the traffic
passing through the hub and to configure
each port in the hub.

41. REPEATER
The maximum path between 2
stations on the network should not
be more than 5 segments with 4
repeaters between those segments
and no more than 3 populated
segments.
Host A
Host Z

42. BRIDGES
Bridges are used to connect separate segments of a
network.
Bridges implement the Spanning-Tree Protocol to build a
loop free network topology. This means that on a network
,one or more bridges may be blocked if they are forming a
loop . Bridges communicate with each other, exchanging
information such as priority and bridge interface MAC
address. They select a root bridge and then implement
the Spanning-Tree Protocol.
BRIDGE
Ethernet NetworkLocal Talk Network
LT
LT
LT

43. A network switch is a small hardware device that joins multiple
computers together within one local area network (LAN).
Network switches are capable of inspecting data packets as they
are received, determining the source and destination device of
each packet, and forwarding them appropriately.
Allow several users to send information over a network at the
same time without slowing each other down.
SWITCH
SWITCH

44. • A device to interconnect SIMILAR networks, e.g. similar
protocols and workstations and servers.
• A router is an electronic device that interconnects two or more
computer networks, and selectively interchanges packets of data
between them.
• Each data packet contains address information that a router can
use to determine if the source and destination are on the same
network, or if the data packet must be transferred from one
network to another.
ROUTER
SWITCH
ROUTER
The Internet

45. • Gateways are used to
interconnect two different
networks having different
protocols.
• Networks using different
protocols use different
addressing formats.
• A gateway is a network
point that acts as an
entrance to another
network.
• Gateways are also called
protocol converters.
GATEWAY
GATEWAY
INTERNET
LOCAL AREA NETWORK

46. FIREWALL
• A FIREWALL is a network security system that monitors and
controls the incoming and outgoing network traffic based on
predetermined security rules.
• A FIREWALL typically establishes a barrier between a trusted,
secure internal network and another outside network, such as
internet, that is assumed not to be secure or trusted.

47. SWITCHING TECHNOLOGIES
In large networks there might be
multiple paths linking sender and
receiver. Information may be
switched as it travels through
various communication channels.
switching
Circuit Switching
Packet Switching
Message
Switching
Circuit switching is a
technique that directly
connects the sender and
the receiver in an unbroken
path.
In packet switching methods, a
message is broken into small
parts, called packets.
With message switching there is n
need to establish a dedicated pat
between two stations.
This type of network is called a
store-and-forward network.

48. CIRCUIT SWITCHING
In this technique one node directly
connected to sender and receiver is
an unbroken part.
You can see 1,3,5 are the broken
part. This technique one dedicated
path is exists between the both
ends until the connection is
Terminated.
1 4
3
2 5

49. Node A
Node B
Node C
Node D
Node F
Node E Node H
Node gHost 1
Host 2
PACKET SWITCHING

50. Sender
Receiver
Intermediate Switching devices
message
message
Store full message and
then forward
Store full message and
then forward
MESSAGE SWITCHING

51. COMMUNICATION TYPES
SIMPLEX
Data can be sent only through
one direction.
HALF DUPLEX
FULL DUPLEX

52. Only
Receiver
Only
Sender
SIMPLEX

53. HALF DUPLEX

54. FULL DUPLEX

55. SIGNAL TYPES

56. EXAMPLE OF ANALOG SIGNALS
Analog Signals
Amplitude value
Frequency(time)
Peak Amplitude
Waves

57. EXAMPLES OF DIGITAL SIGNALS
Digital Signals
Amplitude value
Frequency(time)
Bit Rate
Digital signals

58. THANK YOU!