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Unit 12: Application Layer

Applications of multimedia packages are found in all walks of life. With the advancement Notes
and innovation in presentation tools of multimedia, the multimedia applications have
been giving impressions of virtual reality to its end users.
Simple Mail Transfer Protocol (SMTP) is used to transfer mails from one computer system
to another computer system attached to the same network or different networks and uses
end-to-end delivery in which an SMTP client machine contacts the destination host’s SMTP
server directly to deliver the mail.

The HTTP uses TCP transport service through sockets to transfer the data. The HTTP client
initiates the TCP connection by using sockets on port 80 to the HTTP server. After accepting
the connection from the client, the server response back to the client requests with the
HTML pages and the objects. Thus, HTML pages and other objects are exchanged between
the client browser and web server. After serving the client request, the TCP connection is
terminated.

Multimedia is nothing but the processing and presentation of information in a more
structured and understandable manner using more than one media such as text, graphics,
animation, audio and video.

12.6 Keywords

Browser: A browser is software, which your computer uses to view WWW documents and access
the Internet.
Client: A client is a software entity within client machine that initiates a service request from a
server.
Client Server Architecture: The client server architecture includes a host machine that makes a
request to connect to another host machine for making available some services.
Cookies: Cookies that are small piece of data stored into the client’s disk are used to identify the
web browser.
Datagram Sockets: They are used for connectionless communication in which reliability is not
important.

Domain Name System (DNS): It provides the protocol, which allows clients and servers to
communicate with each other. DNS enables a system to use a resolver, which resolves the host
name to IP address understandable by server.

Electronic Mail: It refers to the electronic version of the postal mail that uses user agent and
message transfer agent to transport the message at the destination mailboxes. Multimedia.
Hyper Text Transfer Protocol: HTTP is a network protocol which is used to access any website.

HTTP Connections: Two types of HTTP connections are non-persistent (HTTP/1.0) and persistent
(HTTP/1.1).
HTTPS: The HTTPS is a secure version of HTTP and indicates to use the port 443 instead of port 80.

Iterative: A client program is said to be running iteratively when it runs one by one.
Multimedia: Multimedia means the combination of two or more continuous media.
Non-persistent HTTP: This connection works on an individually established TCP connection for
each object to be delivered by the HTTP server.
Persistent HTTP: The persistent HTTP connection enables the same TCP connection to be used
for sending and receiving multiple HTTP requests and responses.

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