Computer Science 2 Marks Each

Spam is the abuse of electronic messaging systems (including most broadcast media, digital delivery systems) to send unsolicited bulk messages indiscriminately.

Bus topology

StarTopology

OR any valid illustration of Bus and Star Topology.

(a) Broad network access (e.g, mobile phones, tablets,
laptops, and workstations)
(b) Resource pooling

PAN

GPRS: General packet Radio service

CDMA: Code Division Multiple Access

Video Conferencing: It is a conference between two or more participants at different locations in real time over
the Internet or a private network using video camera, microphone and speakers.

Chat: It is an application to communicate with a person, a group, or a site on the Internet in real time by typing text.

2G: Better voice service, Speed around 64kbps

3G: Improved data services with multimedia, Speed around 2Mbps

(b) and (c)

(a) Optical Fiber can carry data without any loss

(b) Optical fiber can carry data at the speed of light

Domain Name: It is the unique name that identifies an Internet site

IP Address: It is the unique address for each computer on a network

URL: http://cbseacademic.in/results.html

Domain Name: cbseacademic.in

Independent line of connection allows freedom of removing or adding nodes from the network.

a. Stealing a mouse from someone’s computer.

Client Side Scripting Language: JavaScript (OR VBScript)

Server Side Scripting Language: JSP (OR ASP)

VoIP

JavaScript and VBScript are client side scripts.

JSP and ASP are server side scripts.

Voice over Internet Protocol: It is a communication protocol and transmission technology for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Also, we can say, VoIP are IP telephony, Internet Telephony, Internet telephony and broadband telephony.

Packet switching: In packet switching, a fixed size of data packet that can be transmitted across the network is specified and then the data packets are sent through switching stations to the final destinations. All the packets are stored in the main memory instead of disk. As a result accessing time of packets is reduced.

Message switching: The source computer sends data (message) to the switching station, which stores data in a buffer. It then looks for a free link to another switching station and sends data to that station. This process continues until data is delivered to the destination computer. This type of switching technique is also known as “store and forward” switching.

Two threats to network security are:

(i) Snooping : Unauthorized access of someone else’s data, email etc

(ii) Eavesdropping : Secretly listening someone else’s private communication.

Firewall (both in hardware form or software form) prevents unauthorized access to or from a private network.

A modem is a networking device that allows a computer to connect and communicate with other computers via telephone lines. Modem translates digital signals of a computer into analog signals of a computer (modulation) so that they can travel via telephone lines and again converts received analog data into digital data (demodulation).

LAN - Small computers networks that are confined to localised area are known as Local Area Networs (LAN).
For example office, building , school.

WAN - On the other hand, network spread across countries are known as Wide Area Network. It is a group
of servers that are separated by large distances and tied together. For example Internet.

Resource sharing . For example , a printer can be shared among 20 stand alone computers.

Reliability : A file can have copies on two or more different machines. So if one computer is down or unavailable, other copy can be used.

MAC address refers to the physical address assigned by NIC manufacturer . It is a 6 byte address with each
byte separated by colon.

For example ,20 :A6 :E9 :45 :AF : 2E

IP address refers to the logical address (Unique) assigned to all network on a TCP/IP network. It is a 4 byte address with each byte separated by dot(.).

For example: 192.168.52.2.

Two measures to secure a network are :

(i) Firewall : It helps to prevent unauthorized access to or from a private network.

(ii) Intrusion detection : It is the art and science of sensing when a number of network is being used inappropriately or without authorization.

(i) .com - commercial business

(ii) .org - organization (non profit)

BOSS (Bharat Operating system Solution)

Optical Fibre