Anna University Coimbatore 2009 B.E Electronics

data link layer adds the
header, which describes the
from a specific process on
one computer to a specific
process on a different
computer.
network layer adds a
header, which indicate the
logical address of the sender
and receiver.
source machine' s address
and the destination
machine' s address.
UNIT – V
APPLICATION LAYER
1. What is the purpose of Domain Name System?
Domain Name System can map a name to an address and conversely an
address to name.
2. explain the 3 main division of the domain name space.
Domain name space is divided into 3 various sections: generic domains,
country domains & inverse domain.
Generic domain: describe registered hosts according to their generic behavior, uses
generic suffixes.
Country domain: Uses 2 characters to identify a country as the last suffix.
Inverse domain: obtains the domain name provided the IP address.
3. explain the TCP connections needed in FTP.
FTP establishes 2 connections ranging from the hosts. 1 connection is used
for data transfer, the other for control info. The control connection uses very
simple rules of communication. The data connection needs more complex rules due to
the variety of data kinds transferred.
4. explain the basic model of FTP.
The client has 3 components: the user interface, the client control process,
and the client data transfer process. The server has 2 components: the server
control process and the server data transfer process. The control connection is made
ranging from the control processes. The data connection is made ranging from the data transfer
processes.
5. What is the function of SMTP?
The TCP/IP protocol supports electronic mail on the Internet is called Simple
Mail Transfer (SMTP). It is a system for sending messages to other computer users
based on e-mail addresses. SMTP provides mail exchange ranging from users on the identical
or various computers.
6. What is the difference ranging from a user agent (UA) and a mail transfer agent
(MTA)?
The UA prepares the message, creates the envelope, and puts the message in
the envelope. The MTA transfers the mail across the Internet.
7. How does MIME enhance SMTP?
MIME is a supplementary protocol that allows non-ASCII data to be sent
through SMTP. MIME transforms non-ASCII data at the sender site to NVT ASCII
data and deliverers it to the client SMTP to be sent through the Internet. The server
SMTP at the receiving side receives the NVT ASCII data and delivers it to MIME to

Earning:   Approval pending.