, Computer
Networks
UNIT-I Introduction and Physical Layer
Introduction - Uses of Computer Networks - Network hardware - Network software - Reference Models:
OSI, TCP/IP Reference models - Example Networks: ARPANET, Internet - Physical Layer: Guided
Transmission media: Twisted pairs, coaxial cable, fiber optics - Wireless transmission.
2 MARKS
1. What is Network?
▪ A network is a group of two or more computer systems linked together.
▪ Network is an interconnection of systems to share data and information.
▪ A network is a set of devices (often referred to as nodes) connected by communication links. A
node can be a computer, printer, or any other device capable of sending and/or receiving data
generated by other nodes on the network.
2. Define Computer Network?
A Computer Network or data network is a telecommunications network which allows computers to
exchange data. In computer networks, networked computing devices pass data to each other along
network links (data connections). Data is transferred in the form of packets.
,3. Define Internet or internetwork?
▪ A collection of interconnected networks is called an internetwork or internet.
▪ Internetworking is connecting a computer network with other networks through the use of gateways
that provide a common method of routing information packets between the networks. The resulting
system of interconnected networks is called an internetwork, or simply an internet.
▪ Network is an interconnection of systems to share data and information. Internet is network of
network or collection of heterogeneous networks.
4. What is distributed system?
A distributed system is a collection of independent computers that appear to the users of the system as a
single coherent system.
5. What is meant by Middleware?
▪ Middleware is computer software that provides services to software applications beyond those
available from the operating system.
▪ Software that acts as a bridge between an operating system or database and applications, especially
on a network.
6. What is meant by World Wide Web (WWW)?
World Wide Web (WWW) is a distributed system of inter linked pages that include text, pictures, sound
and other information. It enables easy access to the information available on the internet.
WWW is a repository of information (called resource) distributed all over the world, is defined as a
world-wide networks of networks.
7. Mention the uses of Computer Networks?
The various uses of Computer Networks are
1. Business Applications
2. Home Applications
3. Mobile Users
4. Social Issues
5.
8. What is meant by Virtual Private Networks (VPN)?
Virtual Private Networks (VPN) is a network that is constructed by using public wires (usually the
Internet) to connect to a private network, such as a company's internal network. There are a number of
systems that enable you to create networks using the Internet as the medium for transporting data.
, 9. What is meant by Client?
The client part of a Client-Server architecture. Typically, a client is an application that runs on a personal
computer or workstation and relies on a server to perform some operations. For example, an e-mail
client is an application that enables you to send and receive e-mail.
10. What is meant by Server? List its types?
The data are stored on powerful computers called servers. A computer or device on a network that
manages network resources.
There are many different types of servers.
▪ File server: a computer and storage device dedicated to storing files. Any user on the network can
store files on the server.
▪ Print server: a computer that manages one or more printers, and a network server is a computer
that manages network traffic.
▪ Database server: a computer system that processes database queries.
11. What is Client-Server model?
The client-server model is widely used and forms the basis of much network usage. The most popular
realization is that of a Web application, in which the server generates Web pages based on its database in
response to client requests that may update the database. The client-server model is applicable when the
client and server are both in the same building.
12. What is meant by IP telephony?
▪ IP telephony (Internet Protocol telephony) is a general term for the technologies that use the Internet
Protocol's packet-switched connections to exchange voice, fax, and other forms of information that
have traditionally been carried over the dedicated circuit-switched connections of the public switched
telephone network (PSTN).
▪ Telephone calls between employees may be carried by the computer network instead of by the phone
company. This technology is called IP telephony or Voice over IP (VoIP) when Internet technology is
used.
Networks
UNIT-I Introduction and Physical Layer
Introduction - Uses of Computer Networks - Network hardware - Network software - Reference Models:
OSI, TCP/IP Reference models - Example Networks: ARPANET, Internet - Physical Layer: Guided
Transmission media: Twisted pairs, coaxial cable, fiber optics - Wireless transmission.
2 MARKS
1. What is Network?
▪ A network is a group of two or more computer systems linked together.
▪ Network is an interconnection of systems to share data and information.
▪ A network is a set of devices (often referred to as nodes) connected by communication links. A
node can be a computer, printer, or any other device capable of sending and/or receiving data
generated by other nodes on the network.
2. Define Computer Network?
A Computer Network or data network is a telecommunications network which allows computers to
exchange data. In computer networks, networked computing devices pass data to each other along
network links (data connections). Data is transferred in the form of packets.
,3. Define Internet or internetwork?
▪ A collection of interconnected networks is called an internetwork or internet.
▪ Internetworking is connecting a computer network with other networks through the use of gateways
that provide a common method of routing information packets between the networks. The resulting
system of interconnected networks is called an internetwork, or simply an internet.
▪ Network is an interconnection of systems to share data and information. Internet is network of
network or collection of heterogeneous networks.
4. What is distributed system?
A distributed system is a collection of independent computers that appear to the users of the system as a
single coherent system.
5. What is meant by Middleware?
▪ Middleware is computer software that provides services to software applications beyond those
available from the operating system.
▪ Software that acts as a bridge between an operating system or database and applications, especially
on a network.
6. What is meant by World Wide Web (WWW)?
World Wide Web (WWW) is a distributed system of inter linked pages that include text, pictures, sound
and other information. It enables easy access to the information available on the internet.
WWW is a repository of information (called resource) distributed all over the world, is defined as a
world-wide networks of networks.
7. Mention the uses of Computer Networks?
The various uses of Computer Networks are
1. Business Applications
2. Home Applications
3. Mobile Users
4. Social Issues
5.
8. What is meant by Virtual Private Networks (VPN)?
Virtual Private Networks (VPN) is a network that is constructed by using public wires (usually the
Internet) to connect to a private network, such as a company's internal network. There are a number of
systems that enable you to create networks using the Internet as the medium for transporting data.
, 9. What is meant by Client?
The client part of a Client-Server architecture. Typically, a client is an application that runs on a personal
computer or workstation and relies on a server to perform some operations. For example, an e-mail
client is an application that enables you to send and receive e-mail.
10. What is meant by Server? List its types?
The data are stored on powerful computers called servers. A computer or device on a network that
manages network resources.
There are many different types of servers.
▪ File server: a computer and storage device dedicated to storing files. Any user on the network can
store files on the server.
▪ Print server: a computer that manages one or more printers, and a network server is a computer
that manages network traffic.
▪ Database server: a computer system that processes database queries.
11. What is Client-Server model?
The client-server model is widely used and forms the basis of much network usage. The most popular
realization is that of a Web application, in which the server generates Web pages based on its database in
response to client requests that may update the database. The client-server model is applicable when the
client and server are both in the same building.
12. What is meant by IP telephony?
▪ IP telephony (Internet Protocol telephony) is a general term for the technologies that use the Internet
Protocol's packet-switched connections to exchange voice, fax, and other forms of information that
have traditionally been carried over the dedicated circuit-switched connections of the public switched
telephone network (PSTN).
▪ Telephone calls between employees may be carried by the computer network instead of by the phone
company. This technology is called IP telephony or Voice over IP (VoIP) when Internet technology is
used.
