Short Question And Answer Computer Network Set-5

1. What are the responsibilities of Application Layer?
The Application Layer enables the user, whether human or software, to access the network. It provides user interfaces and support for services such as e-mail, shared database management and other types of distributed information services

  •  Network virtual Terminal
  •  File transfer, access and Management (FTAM)
  •  Mail services
  •  Directory Services

2. What is Encapsulation and De-capsulation ?
To send a message from one application program to another, the TCP/UDP protocol encapsulates and de-capsulate messages.

3. What is DNS?
Domain name service is the method by which Internet address in mnemonic form such are converted into the equivalent numeric IP address such as

4. What is Fully Qualified Domain Name?
If a label is terminated by a null string is called a Fully Qualified Domain Name,

5. What is Generic Domains?
Generic domain define registered hosts according to their generic behaviour. Each node in the tree defines a domain, which is an index to the domain name space database
Eg. com – Commercial organizations
edu – Educational institutions
gov – Government institutions

6. What is simple mail transfer protocol?
The TCP/IP protocol that supports electronic mail on the internet is called Simple Mail Transfer Protocol (SMTP). It is a system for sending messages to other computer users based on email addresses.

7. What is User Agent?
A user Agent is defined in SMTP, but the implementation details are not. The UA is normally a program used to send and receive mail

8. What do you mean by File transfer protocol?
It is a standard mechanism provided by the internet for copying a file from one host to another

9. What are the two types of connections in FTP?
The two types of connections in FTP are

  •  Control connection
  •  Open connection

10. Define HTTP.
It is used mainly to access data on the World Wide Web. The protocol transfer data in the form of plaintext, hypertext, audio, video and so on

11. What are the types of messages in HTTP transaction?
The types of messages in HTTP transaction are

  •  Request messages
  •  Response messages

12. What are the parts of a browser?
The parts of a browser are

  •  A controller
  •  A client program
  •  Interpreter

13. Name the four aspects of security.

  • Privacy
  • Authentication
  • Integrity
  • Non-repudiation

14. Define Cryptography.
The science and art of manipulating messages to make them secure.

15, Define authentication.
It means that the receiver is sure of the sender identity.

16. What do you mean by encryption?
The process of converting plain text to cipher text.

17. Define Privacy
It means that sender and receiver expect confidentiality.

18. What do you mean by Symmetric key cryptography?
In Symmetric key cryptography both the parties will use the same key.

19. What are steps to transfer a mail message?
The steps in transferring a mail message are
a) Connection establishment
b) Mail transfer
c) Connection termination

20. What is POP?
Post Office Protocol, version3 (POP3) and Internet Mail Access Protocol version4 (IMAP4) are protocol used by a mail server in conjunction with SMTP to receive and hold mail for hosts.