Definition of Protocols

A network or communication protocol is a set of rules for communicating between computing devices which governs format, timing, sequencing, and error control. Without these rules, the computer cannot make sense incoming/outgoing bits A protocol set a rules to identify one another in a network, the form of the data during transmission process, and how data is processed before it reaches its final destination. Computers can communicate only if the protocol used by a computer in the network is compatible with the protocol used by another computer. The rules include guidelines which regulates a network access method, allowed physical topologies, types of cabling, and the speed of data transfer.

Most commonly used network protocols 

1. TCP/IP (Transmission Control Protocol/Internet Protocol): TCP/IP is a layered set of protocols TCP is reliable, but complex transport-layer protocol. It is stream connection-oriented and reliable transport protocol. TCP/IP is the protocol used by Internet. It adds connection-oriented and reliability features. TCP is responsible for making sure that the data is transmitted to other end. It keeps track of what is sent, and re transmits any data that has not reached its destination. The Internet Protocol (IP) is the principal communication protocol used for transmitting data packets across and network using the Internet Protocol Suite. Internet exist due to TCP/IP.

2. FTP (File Transfer Protocol): This protocol is used for transferring data between client and server over TCP/IP (Internet). Hence, it is responsible for uploading and downloading files to and from the server.

3. UDP (User Datagram Protocol): UDP is simple, connection less, unreliable transport protocol. It performs very limited error checking. It is mainly used for transmitting multimedia data, which requires faster transmission and error checking is not used.

4. SMTP (Simple Mail Transfer Protocol): SMTP is a standard protocol for transmitting electronic mail (email) by the internet. It is a Internet mail protocol. It is a TCP/IP protocol used to send emails

5. POP (Post Office Protocol): POP is also a protocol for transmitting email. It is simple but has limited functionality. It is an application layer Internet standard protocol used by clients to access e-mail from a server over a TCP/IP connection i.e. internet. POP3 (POP version 3) is used at present. POP3 is supported by most modern webmail services such as Gmail and Yahoomail.

6. HTTP (Hypertext Transfer Protocol): HTTP networking protocol for distributed, collaborative, hypermedia information systems. It is used transmitting hypertext or HTML based document. It is the foundation of data communication for the World Wide Web used by web browser to communication with respective servers.

7. HTTPS (Hypertext Transfer Protocol Secure): HTTPS is combination of Protocol with the SSL/TLS protocol to provide encrypted identification of a network. HTTPS connections are often used in World Wide Web for sensitive transactions. The main objective of HTTPS is to create a secure channel over an insecure network