Basic Internet Protocols

1. File Transfer Protocol (FTP) :

The file transfer protocol sets the rules for transferring files between computers. When user wants to download a file from the server FTP is used. There are various issues that must be solved during such file transfer. These issues can be described as follows.

1. client must have an authority to download particular file.

2. the hardware and software on both the computers might be different.

3. the data interpretation and data formats on client and server might be different.

FTP provides the mechanism to handle these issues internally and remains free from all these complications. FTP uses two connections between client and server. One connection is used for actual data transfer and other is used for control information (used for commands). This seperation of data and commands makes the FTP more efficient.

2. Hyper Text Transfer Protocol (HTTP) :

The Hyper Text Transfer Protocol (HTTP) is a request/response protocol. It is a communication protocol used to transfer the information on local area network and World Wide Web (WWW).

It's the network protocol used to deliver virtually all files and other data (collectively called resources) on the World Wide Web, whether they're HTML files, image files, query results, or anything else. Usually, HTTP takes place through TCP/IP sockets.

A browser is an HTTP client because it sends requests to an HTTP server (Web server), which then sends responses back to the client. The standard (and default) port for HTTP servers to listen on is 80. The GET and POST are two popular methods used by HTTP protocol. It is also called as a stateless protocol because this protocol is not able to maintain the previous conversation/information.

3. Simple Network Management Protocol (SNMP) :

SNMP is a protocol which enables network administrators to manage network devices and to diagnose network problems. The network management system is based on two main elements : a supervisor and agents. The supervisor is the terminal at which the network administrator requests for network management. The agents are found at the level of each interface connecting the managed devices to the network. With the help of these agents information on the different objects (such as switch, hub, router) can be collected. SNMP makes use of UDP connection4. for transferring the SNMP messages. 

4. Post Office Protocol version 3 (POP3) :

POP3 is used by local email clients (such as Microsoft Outlook Express). POP3 makes use of port 110. The POP3 protocol works only at the receivers end and has no works at the sender's end.

The POP protocol has two parts, a client POP i.e. receiver's POP and a server POP i.e. receiver's email server. The client i.e. the receiver opens TCP connection with receiver's POP server. This client must be authenticated first by using the user name and password. Then the client can receive the email from the mailbox.

5. Transmission Control Protocol (TCP) :

The Transmission Control Protocol is used for, 

1. Safe delivery of data.

2. Error detection.

3. Assurance of the correct sequencing of data being received.

This protocol is called connection oriented protocol because before sending the data this protocol requires that two computers have established connections. The TCP allows the transmission of arbitrary amount of data by breaking it into stream of seperate IP packets. These IP packets are numbered so that it could be reassembled properly at arrivals. Along with the data an acknowledgement is also sent/received in order to know whether the reliable connection  has occured or not.

6. User Datagram Protocol (UDP) :

The user datagram protocol is a connectionless protocol without any error detection facility. This protocol is used for simply transmission of data. The UDP is known as an unreliable protocol however this is much faster than TCP.

7. Internet Protocol (IP) :

Internet Protocol (IP) is a network layer protocol which consists of addressing information. Using this information the communication between uniquely addressed computers is possible.

There are two functionalities provided by Internet Protocol :

* Decomposition of the initial information flow into packets of standardized size and reassembling of data at the destination.

* The internet protocol routes the packet through successive networks, from the source machine to the destination which can be identified by its IP address.