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WELCOME

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MIS – 404:
Networking and
Operating Systems
Department of BBA
MIS
East West University

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Course Outline
1. Computer Network:
Introduction
Motivation
Classification: LAN, MAN, WAN
2. Network Topology:
Definition
Classification: BUS, TREE, STAR, RING, MESH, HYBRID

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Computer Network
Background of Network
 When there was no network
Motivation
 Resource Sharing
Resource
 Hardware
 Software
 Data/Information

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Computer Network
Definition:
 When a number of computers or devices are
interconnected in a single communication
system
 growth of number & power of computers is
driving need for interconnection
 also seeing rapid integration of voice, data,
image & video technologies

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History of Computer Network

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History of Computer Network

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Classification
Depending upon the area coverage:
 Local Area Network (LAN)
 Metropolitan Area network (MAN)
 Wide Area Network (WAN)

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LAN
• LANs consist of the following
components:
– Computers
– Network interface cards
– Peripheral devices
– Networking media
– Network devices

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LAN

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LAN
• smaller scope
– Building or small campus
• usually owned by same organization
as attached devices
• data rates much higher
• switched LANs, eg Ethernet
• wireless LANs

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LAN
• LANs make it possible for businesses that
use computer technology to locally share
files and printers efficiently, and make
internal communications possible.
• A good example of this technology is e-mail.
• They tie data, local communications, and
computing equipment together.

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LAN

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LAN
• Some common LAN technologies are:
– Ethernet
– Token Ring
– FDDI

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MAN
• Metropolitan Area Network
• A MAN is a network that spans a
metropolitan area such as a city or
suburban area.
• A MAN usually consists of two or more
LANs in a common geographic area.
• For example, a bank with multiple branches
may utilize a MAN.

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MAN

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MAN
• middle ground between LAN and WAN
• private or public network
• high speed
• large area
• Typically, a service provider is used to
connect two or more LAN sites using private
communication lines or optical services.
• A MAN can also be created using wireless
bridge technology by beaming signals
across public areas.

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WAN: Internet Architecture

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WAN
• span a large geographical area
• rely in part on common carrier circuits
• alternative technologies used include:
– circuit switching
– packet switching
– frame relay
– Asynchronous Transfer Mode (ATM)

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WAN
• WANs are designed to do the following:
– Operate over a large geographically separated
areas
– Allow users to have real-time communication
capabilities with other users
– Provide full-time remote resources connected to
local services
– Provide e-mail, World Wide Web, file transfer,
and e-commerce services

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WAN
• Some common WAN technologies are:
– Modems
– Integrated Services Digital Network (ISDN)
– Digital Subscriber Line (DSL)
– Frame Relay
– US (T) and Europe (E) Carrier Series – T1, E1,
T3, E3
– Synchronous Optical Network (SONET)

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WAN: Internet Architecture

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Storage Area Network
• A SAN is a dedicated, high-performance
network used to move data between servers
and storage resources.
• Because it is a separate, dedicated network,
it avoids any traffic conflict between clients
and servers.
• SAN technology allows high-speed server-
to-storage, storage-to-storage, or server-to-
server connectivity.

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Storage Area Network

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Storage Area Network
• This method uses a separate network infrastructure that
relieves any problems associated with existing network
connectivity.
• SANs offer the following features:
– Performance – SANs enable concurrent access of disk or tape
arrays by two or more servers at high speeds, providing
enhanced system performance.
– Availability – SANs have disaster tolerance built in, because
data can be mirrored using a SAN up to 10 kilometers (km) or 6.2
miles away.
– Scalability – Like a LAN/WAN, it can use a variety of
technologies. This allows easy relocation of backup data,
operations, file migration, and data replication between systems.

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Virtual Private Network (VPN)
• A VPN is a private network that is
constructed within a public network
infrastructure such as the global Internet.
• Using VPN, a telecommuter can access the
network of the company headquarters
through the Internet by building a secure
tunnel between the telecommuter’s PC and
a VPN router in the headquarters.

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Virtual Private Network (VPN)

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Virtual Private Network (VPN)
Benefits of VPN:
• A VPN is a service that offers secure, reliable
connectivity over a shared public network
infrastructure such as the Internet.
• VPNs maintain the same security and management
policies as a private network.
• They are the most cost-effective method of
establishing a point-to-point connection between
remote users and an enterprise customer's
network.

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Intranet
• One common configuration of a LAN is an Intranet.
• Intranet Web servers differ from public Web
servers in that the public must have the proper
permissions and passwords to access the Intranet
of an organization.
• Intranets are designed to permit access by users
who have access privileges to the internal LAN of
the organization.
• Within an Intranet, Web servers are installed in the
network.
• Browser technology is used as the common front
end to access information such as financial data or
graphical, text-based data stored on those servers.

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Intranet & Extranet

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Extranet
• Extranets refer to applications and services
that are Intranet based, and use extended,
secure access to external users or
enterprises.
• This access is usually accomplished
through passwords, user IDs, and other
application-level security.
• Therefore, an Extranet is the extension of
two or more Intranet strategies with a
secure interaction between participant
enterprises and their respective intranets.

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Bandwidth
Bandwidth has been defined as the
amount of information that can flow
through a network in a given time.

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Bandwidth

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