What is a networking protocol?

Overview

Protocol, in networking, is a set of rules that devices must follow to communicate with each other. Each network layer in the OSI model has a separate set of protocols. These protocols are defined in documents called RFCs.

RFCs

RFCs, also known as "request for comments," are official documents from standard-setting bodies of the internet, mainly the IETF (Internet Engineering Task Force). RFCs list communication protocols and specifications. Some of the protocols that are defined in RFCs and widely used are listed below:

FTP, SMTP, and HTTP

These application-layer protocols work on top of the transport layer to provide communication between different applications. Each of these has a separate role:

• FTPFile Transfer Protocol: It is used to transfer files from a server to a client in a network.
• SMTPSimple Mail Transfer Protocol: It is used to send and receive emails.
• HTTPHyper-Text Transfer Protocol: It is used to transmit hypermedia documents such as HTML from a server to a browser.

TCP and UDP

TCP and UDP are both transport layer protocols that provide end-to-end communication between different devices. However, there are key differences in how they work and the features they provide:

• TCPTransmission Control Protocol: This protocol establishes a connection before sending any data between devices. It provides reliable data delivery by re-sending data packets in case of loss and ensuring their delivery. Data is sent in the form of a data stream.
• UDPUser Datagram Protocol: This protocol does not require a connection to be established before sending data; hence, it is unreliable. However, it is much faster than TCP as there is no data overhead. Data is sent in the form of packets with fixed boundaries.

ICMP

ICMPInternet Control Message Protocol is a network layer protocol that allows devices to communicate network issues and evaluate network performance. A common command-line tool, traceroute, also uses ICMP.

PPP

PPPPoint-to-Point Protocol, also known as RFC 1661, is a data link layer protocol used to transmit data packets directly between two peers. It is a byte-oriented protocol that transmits data in frames.