This document discusses computer networks and their components. It defines a computer network as a set of communication elements like computers and routers connected by communication links such as fiber optic cables. These networks allow for resource sharing, information exchange, and the creation of a global electronic society. The document outlines the hardware components of networks, including servers, clients, transmission media, and connecting devices. It also discusses the software components, specifically network operating systems and protocol suites that govern communication.

1. UNIT 1
Introduction to Computer Networks
Part 1 Networking Devices
Laishram Darmoni
ProjectAssociate
NIELIT IMPHAL
MCA 2nd Semester

2. Computer Networks
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A set of communication elements connected by communication links
➭ Communication elements
● Computers, printers, mobile phones, …
● Routers, switches, ...
➭ Communication links
● optic fiber
● coaxial cable
● twistedpair
● wireless (radio, microwave, satellite)
➭ Topologies
● Ring, Star, Bus, Tree, Mesh

3. Computer Networks
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A software/hardware infrastructure
➭ Shareresources
● data, files, computing power,video,…
➭ Information highway
● communication between geographicallydispersedusers
➭ Electronic Society
● Cyberspace
● Virtual globalnation

4. Computer Networks
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• Computer Network
– an interconnectedcollection of autonomouscomputers
➭ Internet: “network of networks”
– looselyhierarchical
– publicInternet versusprivate intranet
➭ WWWa distributed systemsrun on the top of Internet
• Distributed System
– High degreeof cohesivenessandtransparency
– A software system built on top of a network

5. Uses of Computer Networks
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➭ BusinessApplications
➭ Home Applications
➭ Mobile Users
➭ SocialIssues

6. Uses of Computer Networks: Business Application
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Business Applications of Network
• Resourcesharing(hardware,software, information,…)
• Doing businesselectronically(B2B, B2C, e-commerce)
• Providingcommunication medium(e-mail,videoconferencing)
A network with two clients and one server.

7. Uses of Computer Networks: Business Application
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Goals of Networks for Companies
• Resource sharing: equipment, programs,data
• highreliability
– replicated data
– hardware
• Saving money
– mainframe: 10 times faster, but 1000 times more
expensive than PC
– client-servermodel
• Scalability
– mainframe:replacea largerone
– client-servermodel:addmoreservers
• Communication mediumfor separated employees

8. Home Network Application
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Home Network Applications
• Accessto remote information
• Person-to-personcommunication
• Interactive entertainment
• Electronic commerce
In a peer-to-peer system there are no fixed clients and servers

9. Home Network Application
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Networks for People
– Accessto remote information
• e.g.: financial,shopping,customized
newspapers,on-linedigital library,
WWW
– Person-to-personcommunication
• email,video conference,newsgroup
– Interactive entertainment
• VOD, interactive moviesor TVs, game
playing
Some forms of e-commerce

10. Home Network Application
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Networks for People
– Accessto remote information
• e.g.: financial, shopping, customized
newspapers,on-linedigital library, WWW
– Person-to-personcommunication
• email,video conference,newsgroup
– Interactive entertainment
• VOD, interactive moviesor TVs, gameplaying
In a peer-to-peer system there are no fixed clients and servers

11. Network Component
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• Computer networks components comprise both
physical parts as well as the software required for
installing computer networks, both at organizations
andat home.
• The hardware components are the server, client,
peer,transmissionmedium,andconnecting devices.
• The software components are operating system and
protocols.

12. Hardware Component
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• Peers: Computers that provide as well as receive
servicesfrom other peersin a workgroupnetwork.
• Transmission Media: Channels through which data
is transferred from one device to another in a
network. .
• Connecting Devices: − Connecting devices act as
middleware between networks or computers, by
bindingthe network mediatogether.
• Servers: High-configuration computers that manage the resources of the network. The network operating
system is typically installed in the server and so they give user accesses to the network resources. Servers
canbe of variouskinds:file servers,databaseservers,printserversetc.
• Clients: Computers that request and receive service from the servers to access and use the network
resources.

13. Software Component
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• Networking Operating System: Network Operating
Systems is typically installed in the server and
facilitate workstations in a network to share files,
database,applications,printers etc.
• Protocol Suite: A protocol is a rule or guideline
followed by each computer for data communication.
Protocol suite is a set of related protocols that are
laid down for computer networks. The two popular
protocolsuites are
• OSI Model( Open System Interconnections)
• TCP / IP Model