This document provides an overview of computer networks. It defines a computer network as a collection of devices connected to allow data exchange. It then describes different types of networks including personal area networks (PANs), local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). Finally, it discusses common network architectures such as client-server, peer-to-peer, and hybrid architectures.

2. COMPUTER
NETWORKS
CREATED BY:
USMAN SHAFIQ
WALEED ZAFAR
FAHAD NADEEM
SHEHROZ KHAN

4. CONTENTS
INTRODUCTION
COMPUTER NETWORK
TYPES OF NETWORK
CLASSIFICATION OF NETWORK ARCHITECTURE

5. INTRODUCTION
 A computer network is a telecommunications network that allows computers
to exchange data.
 The physical connection between networked computing devices is
established using either cable media or wireless media.
 The best-known computer network is the internet.

6. COMPUTER NETWORK
 A collection of computing devices that are connected in various ways
in order to communicate and share resources.
 Usually, the connections between computers in a network are made
using physical wires or cables.
 However, some connections are wireless, using radio waves or
infrared signals.

7. TYPES OF NETWORK
 Based on the size and the coverage area, networks
are categorized into the following types:
 Personal Area Networks (PANs)
 Local Area Networks (LANs)
 Metropolitan Area Networks (MANs)
 Wide Area Networks (WANs)

8.  PERSONAL AREA NETWORKS (PANs)
 A personal area network (PAN) is a computer network used for communication
among computer and different information technological devices close to one
person.
 Is a small network established for communication between different
devices, such as laptops, computers, mobiles, and PDAs.
 A pan may include wired and wireless devices.
 The reach of a pan typically extends to 10 meters.

9.  LOCAL AREA NETWORK(LANs)
 A local area network (LAN) is a network that connects computers
and devices in a limited geographical area such as a home, school,
office building, or closely positioned group of buildings.
 Each computer or device on the network is a node.
 Wired LANs are most likely based on Ethernet technology.

10. LOCAL AREA NETWORK

11. HISTORY
 The increasing demand and use of computers in
universities and research labs in the late 1960s generated
the need to provide high-speed interconnections between
computer systems.

12.  A 1970 REPORT FROM THE LAWRENCE RADIATION
LABORATORY DETAILING THE GROWTH OF THEIR
"OCTOPUS" NETWORK GAVE A GOOD INDICATION OF
THE SITUATION.

13. OCTOPUS NETWORK’S FIGURE

14. CABLES THAT ARE USED IN IN LOCAL AREA NETWORK
 Early LAN cabling had generally
been based on various grades of
coaxial cable.
 Shielded twisted pair was used
in IBM's Token Ring LAN
implementation.

15. CABLES THAT ARE USED IN IN LOCAL AREA NETWORK
 But in 1984, StarLAN showed the
potential of simple unshielded
twisted pair by using Cat3 cable—
the same simple cable used for
telephone systems.
 This led to the development of 10-
Base-T (and its successors)
and structured cabling which is still
the basis of most commercial LANs
today.

16. CABLES THAT ARE USED IN IN LOCAL AREA NETWORK
 Fiber-optic cabling is common for
links between switches, but fiber to
the desktop is uncommon.

17. TECHNICAL ASPECTS
 Network topology describes the layout of
interconnections between devices and
network segments.
 At the Data Link Layer and Physical Layer, a
wide variety of LAN topologies have been
used, including ring, bus, mesh and star, but
the most common LAN topology in use
today is switched Ethernet.

18. TECHNICAL ASPECTS
 At the higher layers, the Internet Protocol
(TCP/IP) has become the standard, replacing
NetBEUI, IPX/SPX, AppleTalk and others.
 Simple LANs generally consist of one or
more switches. A switch can be connected to
a router, cable modem, or ADSL modem for
Internet access

19. WLAN (WIRELESS LOCAL AREA NETWORK)
 A WLAN is a wireless computer network that links two or
more devices using a wireless distribution method
within a limited area such as a home, school, computer
laboratory, or office building.

20. WLAN (WIRELESS LOCAL AREA NETWORK)
 Most modern WLANs are based on IEEE 802.11 standards,
marketed under the Wi-Fi brand name.
 Wireless LANs have become popular in the home due to ease
of installation, and in commercial complexes offering wireless
access to their customers; often for free.

21. WHAT IS IEEE 802.11?
 IEEE 802.11 is a set of media access control (MAC) and
physical layer specifications for implementing wireless local
area network (WLAN) computer communication in the 2.4,
3.6, 5 and 60 GHz frequency bands.

22. VIRTUAL LOCAL AREA NETWORK
 A VLAN allows several networks to work virtually as a
LAN.
 One of the most beneficial elements of a VLAN is that
it removes latency in the network, which saves
network resources and increases network efficiency.

23. VLAN TRUNKING PROTOCOL
 (VTP) is a Cisco proprietary protocol that propagates the
definition of Virtual Local Area Networks (VLAN) on the
whole local area network.
 VTP carries VLAN information to all the switches.

24. WHY USE VLAN?
 To create more flexible designs that group users by
department, or by groups that work together
instead of by physical location.
 To segment devices into smaller LANs (Broadcast
Domains) to reduce overhead caused to each host
in the LAN.

25. WHY USE VLAN?
 To reduce the workload for the Spanning Tree Protocol
(STP) by limiting a VLAN to a single access switch.
 To ensure better security by keeping hosts that work with
sensitive data on a separate VLAN.

26. TYPES OF VLAN
 STATIC VLAN.

27. TYPES OF VLAN
 Dynamic VLAN.

28.  METROPOLITAN AREA NETWORK (MAN)
 It is relatively larger than LAN and extends across a city
or a metropolitan.
 It is created by connecting two or more LANs located at
different locations in a city.

29. EXAMPLE OF MAN
• The best example is television cable network available in many
cities.

30. STANDARD OF MAN
 DQDB, Distributed Queue Dual Bus, is the metropolitan area
network standard for data communication.
 It is specified in the IEEE 802.6 standard.
 The reach of a MANs typically extends up to 20 miles (30 km)
long.
 A MANs operate at speeds of 34 to 155 Mbit/s.

31. WHY USE MAN?
 To Links between LANs with Cables and Wireless
media like microwaves, radio waves, or infra-red
laser links.

32. WHAT IS BMAN?
 BMAN (Broadband Metropolitan Area Network) is a
telecommunications service from Sprint in the U.S.

33. WHAT IS BMAN?
 BMAN provides corporate users in a metropolitan area with
broadband access to the internet on optical fiber lines in a system
that preserves a connection even when one line is cut or fails.
 Using existing and supplemented infrastructure, BMAN uses a
series of interlocking rings so that a connection can be restored
within 60 milliseconds if a single line goes down.

34. WIDE AREA NETWORK(WANs)
 A wide area network (WAN) is a computer network that covers a large
geographic area such as a city, country, or spans even intercontinental
distances.

35. Wide Area Network
 A WAN uses a communications channel that combines many
types of media such as telephone lines, cables, and air
waves.

36. Wide Area Network
 A WAN often makes use of transmission facilities provided by
common carriers, such as telephone companies.

37. EXAMPLE OF WAN
 One of the most prominent examples of the existing wans
is the Internet.

38. WAN
Leased Lines
 WANs are often built using leased lines.
 At each end of the leased line, a router connects the LAN on
one side with a second router within the LAN on the other.
 Leased lines can be very expensive.

39. Circuit Switching and Packet Switching
 WANs can also be built using less costly circuit
switching or packet switching methods.
WAN

40. CLASSIFICATION OF NETWORK ARCHITECTURE
The architecture of a network is a logical design that
determines how the devices in the network communicate.
The commonly used architectures for computer networks are:
 Client-server architecture.
 Peer-to-peer architecture.
 Hybrid architecture.

41. CLIENT-SERVER ARCHITECTURE
 On a network built using the client-server architecture, the
devices communicate to other devices through a central
computer referred to as a server.
 The server is a terminal with high processing power, which
provides services for the other computers on the network.
 The client is a terminal that accesses the resources
available on a server.

42. PEER-TO-PEER ARCHITECTURE
 On a network built using the peer-to-peer architecture, no specific
distinction exists between a client and a server.
 Any node can provide a service as well as send a request for a
service from another node on the network.
 The peer-to-peer network architecture allows sharing of resources,
data, and users.
 Each node on the network has full control over the network
resources.

43. Hybrid Architecture
 A hybrid, in general, is a composition of two different types
of elements.
 A hybrid network architecture is created to get the benefits
of both, the peer-to-peer and the client-server
architectures, in a network.

44. REFERENCES
 Computer Networks
(Andrew S.Tanenbaum)
 Data & Computer communications
(William Stallings)
 http://en.wikipedia.org
 http://www.networkcomputing.com
 http://www.networkworld.com
 http://www.entrecomputer.com

45. THANK YOU FOR TOLERATING
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