Question

Computer essentials wasn’t in the subject search please get my question to the right tutor

2. List six protocols that are used on the Internet and what they are used for. Protocols Description/Use 2. 3. 4. 5. 6.

Answer 1

1.Transmission Control Protocol (TCP)

TCP is a connection oriented protocol and offers end-to-end packet delivery. It acts as back bone for connection.It exhibits the following key features:

• Transmission Control Protocol (TCP) corresponds to the Transport Layer of OSI Model.

• TCP is a reliable and connection oriented protocol.

• TCP offers:

  • Stream Data Transfer.

  • Reliability.

  • Efficient Flow Control

  • Full-duplex operation.

  • Multiplexing.

• TCP offers connection oriented end-to-end packet delivery.

• TCP ensures reliability by sequencing bytes with a forwarding acknowledgement number that indicates to the destination the next byte the source expect to receive.

• It retransmits the bytes not acknowledged with in specified time period.

2.Internet Protocol (IP)

Internet Protocol is connectionless and unreliable protocol. It ensures no guarantee of successfully transmission of data.

In order to make it reliable, it must be paired with reliable protocol such as TCP at the transport layer.

Internet protocol transmits the data in form of a datagram

• The length of datagram is variable.

• The Datagram is divided into two parts: header and data.

• The length of header is 20 to 60 bytes.

• The header contains information for routing and delivery of the packet.

3.User Datagram Protocol (UDP)

Like IP, UDP is connectionless and unreliable protocol. It doesn’t require making a connection with the host to exchange data. Since UDP is unreliable protocol, there is no mechanism for ensuring that data sent is received.

4.File Transfer Protocol (FTP)

FTP is used to copy files from one host to another. FTP offers the mechanism for the same in following manner:

• FTP creates two processes such as Control Process and Data Transfer Process at both ends i.e. at client as well as at server.

• FTP establishes two different connections: one is for data transfer and other is for control information.

• Control connection is made between control processes while Data Connection is made between

• FTP uses port 21 for the control connection and Port 20 for the data connection.

5.Telnet

Telnet is a protocol used to log in to remote computer on the internet. There are a number of Telnet clients having user friendly user interface. The following diagram shows a person is logged in to computer A, and from there, he remote logged into computer B.

6.Hyper Text Transfer Protocol (HTTP)

HTTP is a communication protocol. It defines mechanism for communication between browser and the web server. It is also called request and response protocol because the communication between browser and server takes place in request and response pairs.

HTTP Request

HTTP request comprises of lines which contains:

Request line

Header Fields

Message body

HTTP Response

Like HTTP request, HTTP response also has certain structure. HTTP response contains:

Key Points

• Status line

• Headers

• Message body

• The second line specifies the header which indicates the domain name of the server from where index.htm is retrieved.

• The first line i.e. the Request line specifies the request method i.e. Get or Post.