CBSE Class 12 Computer Science Computer Networks Worksheet Set B

Very Short Answer

Question. What is network congestion? 
Answer. Network congestion is a specific condition in a network when more data packets are coming to network devices than they can handle and process at a time.

Question. What are the symptoms of network congestion? 
Answer. Excessive packet delay, loss of data packets and retransmission are the symptoms of network congestion.

Question. What is a mail exchange record?
Answer. Mail exchange records are DNS records that are necessary for delivering email to the recipient’s address.

Question. Define IP Address? 
Answer. IP address is a unique numerical label as a string of numbers separated by dots, used to identify a device on the internet.

Question. What do you mean by SMTP?
Answer. SMTP (Simple Mail Transfer Protocol) is used for sending emails across the internet.

Short Answer 

Question. What is the difference between remote desktop connection and remote login? 
Answer. Remote desktop collection is a technology that allows us to sit at a computer (the client computer) and connect to the remote computer (the host computer) in a different
location where as a remote login facility permits a user to work on a program on a distant computer based on a valid login credentials. 

Question. What is SSL and how it works? 
Answer. SSL stands for secure sockets layer protocol. It is a mechanism of data transfer over the internet to provide a safe passage for the transmission of data. The working of SSL requires that the website has SSL certificate installed which ensures its authenticity. Once installed the sensitive information is obtained from the user through a secure connection over internet. 

Question. What makes a protocol have a higher bandwidth? 
Answer. In networking bandwidth refers to the transmission capacity of a computer or a communications channel. Higher frequencies offer higher bandwidth. It means they can handle more users, more data at the same time and by transmitting at both the high and low frequencies they can get the 4G signal to propagate into the countryside and also offer high bandwidth to city users. 

Question. Why are protocol needed? 
Answer. In networking, communication occurs between the entities in different systems. Two entities cannot just send bit streams to each other and expect to be understood. For communication, the entities must agree on a protocol. A protocol is a set of rules that govern data communication. 

Question. What is a traceroute command? 
Answer. Traceroute command races the route through the internet from the sending device to the destination computer. The signal generally goes from computer to the internet service provider and then to their provider until it reaches to a provider. It then eventually transfers to the destination provider and finally reaches to the destination computer.

Long Answer 

Question. What do you mean by web address? 
Answer. A location on a net server is called a website. Each website has a unique address called URL. A URL is also referred to as web address. It is an Internet or intranet name that points to a location where a file, directory or website page is hosted. They can also be embedded into the code of web pages in the form of hyperlinks to direct the user to other locations on the Internet. A file’s internet address or URL: 1. The type of server or protocol, 2. The name or address of the server on the internet, 3. The location of the file on the server. URL protocols include HTTP (Hypertext Transfer Protocol) and HTTPS (HTTP Secure) for web resources, mail to for email addresses, FTP for files on a File Transfer Protocol (FTP) server, and telnet for a session to access remote computers.
Most URL protocols are followed by a colon and two forward slashes; “mail to” is followed only by a colon. URLs can only be sent over the Internet using the ASCII character-set. Because URLs often contain non-ASCII characters, the URL must be converted into a valid ASCII format. URL encoding replaces unsafe ASCII characters with a "%" followed by two hexadecimal digits. URLs cannot contain spaces. 

Question. Explain the basic network tools? 
Answer. The basic network tools are:
1. Ping: To test the connectivity between two hosts we can use the PING command. PING determines whether the remote machine can receive the test packet and reply, ping<domain name or ip address>
2. Traceroute: Traceroute is a handy utility to view the number of hops and response time to get to a remote system or website, traceroute or tracert<domain name or ip address>.
3. NSLOOKUP: For diagnosing DNS name resolution problems, we can use the command NSLOOKUP.
4. IPCONFIG Command: The IPCONFIG command displays detailed information about the network we are connected to. The ipcongfig/all command gives more detailed information like DNS server, MAC Address along with other helpful information.
5. WHOIS Command: WHOIS command is a query command that is used to get some information on a specific domain name like who registered it, when was it registered whois -h <domain name>.
6. Speed Test: To check the download and upload speeds of the network connections, we can use the speed test utility. 

Question. Explain about HTTP? 
Answer. The Hypertext Transfer Protocol is an application level protocol with the lightness and speed necessary for distributed collaborative, hypermedia information systems. It is a generic stateless object oriented protocol which can be used for many tasks. HTTP allows an open minded set of methods to be used to indicate the purpose of a request. It builds on the discipline of reference provided by the Uniform Resource Identifier (URI), as a location (URL), or as a name (URN) for indicating the resources on which a method is to be applied. Messages are passed to HTTP in a format similar to that used by Internet Mail and Multipurpose Internet Mail Extensions (MIME). It is also used as a generic protocol for communication between user agents and proxies or gateways to other internet protocols such as Gopher, SMTP, and FTP etc. The HTTP protocol consists of two fairly distinct items: 1. The set of requests from browsers to servers,
2. The set of responses. The HTTP has various built in request methods which allow users to read a web page or to need a web page’s header or to store a webpage or to append to a named resource or to remove the web page or to connect two existing resources or to break an existing connection between two resources.  

Question. Explain the working of Email? 
Answer. We have been writing, sending and receiving emails. Steps for working of email are:
1. We compose and send an email form our email client. Our email client has the recipient’s email address along the email address.
2. Now our email client connects to the outgoing SMTP server and hands over the email message on the required format.
3. The outgoing SMTP first validates the sender details and if valid processes the message for sending and places it in outgoing queue.
4. Next DNS lookup takes place. The SMTP server based on the domain details in the recipient address, looks up the DNS server of the domain and retrieves the recipient server information of the recipient domain.
5. Mail Exchange records are DNS records that are necessary for delivering email to the recipient’s address.
6. Then the SMTP server connects with the recipient email server and sends the emails through the SMTP protocol.
7. The recipient server in turn validates the recipient account and delivers the email to the users mail account.
8. The user logs into own email account and views the received email using email client that will use POP3 or IMAP protocols. 

Question. What are the wireless connectivity protocols?
Answer.  The wireless or cellular connectivity protocols are:
1. 2G (the second generation): 2G is known as GSM was introduced back in 1992 and is a fully digital technology. It allowed some data along with calls in the form of text messages. GSM can handle data speeds up to 250Kbps.
2. 3G (the third generation): 3G was introduced to cater to increasing demand for data by consumers. 3G initially offered speeds of 500 Kbps to 2 Mbps but it is now as high as 20Mbps. It can handle data in the form of text messages and multimedia.
3. 4G (the fourth generation): 4G offers data speeds in the range of 10-15 Mbps,which can go up to 50Mbps and even higher depending on the technology. The operators use many different frequencies for 4G.
4. Wi-Fi: Wi-Fi (wireless fidely) protocol governs the rules to connect to the internet without a direct line form the PC to the ISP. For wi-fi to work we need:
1. A broadband internet connection, 2. A wireless router, 3. A laptop or desktop with a wireless internet card.
5. Wi-fi hotspots: A hotspot is a venue that offers wi-fi access. The public can use a la[top or other suitable portable device to access the internet through a wi-fi hotspots