Communication Protocols

Shaunak Mahajan

5 min readDec 21, 2020

Lets talk about Communication in general, before we talk on Communication Protocols.

Communication is just the act of transferring information from one place, person or group to a different.

What’s in this blog ?

What are Communication Protocols ?
Types of communication protocols
In a Nut-shell

What are Communication Protocols ?

A Communication Protocol are a system of rules that allow two or more entities of a communications system to transmit information via any quite variation of a physical quantity.

Communication protocol are rules for exchanging data between computers, other digital devices and telecom systems.

The Protocol defines the principles , syntax, semantics and synchronization of communication and possible error recovery methods.

Communication protocols are used for software and hardware and can be implemented using both analog and digital communications.
Now let’s talk on some popular communication protocols…

Popular Communication Protocols

File Transfer Protocol (FTP)
Transmission Control Protocol / Internet Protocol (TCP / IP)
User Datagram Protocol (UDP)
Hyper Text Transfer Protocol (HTTP)
Post Office Protocol (POP3)
Internet Message Access Protocol (IMAP)
Simple Mail Transfer Protocol (SMTP)

Types of Communication Protocols

File Transfer Protocol (FTP)

File Transfer Protocol (FTP) is a standard Internet protocol for transmitting files between computers on the web over TCP/ IP connections.

FTP is a client-server protocol. Here the client will ask for a file and the local server will provide the file.
FTP Protocol

How does FTP Work ?

FTP relies on two communications channels between the client and the server. The command channel and the data channel. Command channel is used for controlling the conversation and a the data channel is used for transmitting file content. Conversations between Client and the server is initiated by requesting to download a file.

Using an FTP, a client can do following operations like upload files, download files, delete files, rename files, move and copy files. A user typically must go online to the FTP server.

Now let’s talk about the TCP protocol…

Transmission Control Protocol / Internet Protocol (TCP / IP)

A connection-oriented protocol that facilitates the exchange of messages between computing devices during a network.

One of the most common communication protocol which uses Internet Protocol is the TCP / IP.

How does TCP Work ?

Taking messages from an application / server and dividing them into packets, which can then be forwarded by the devices in the network — switches, routers, security gateways — to the destination. Numbering each packet and reassembling them before handing them off to the server recipient. This is TCP’s working mechanism.

Ensuring a secure connection is established and maintained until the exchange between the servers and receiving the messages is complete makes TCP a connection — oriented protocol.

Giving an example, when an email (using the Simple Mail Transfer Protocol(SMTP)) is sent from an email server, division of the messages into multiple packets, numbering them and forwarding them to IP layer for transport is done by the TCP Layer. Each packet will be transported to the destination email server at the IP Layer. Routes for going to the same place may vary. After the arrival, the IP layer hands it back to the TCP layer, and the packets are reassembled into messages and shown in the Inbox.

Heard about HTTP ? Let’s talk…

Hyper Text Transfer Protocol (HTTP)

The communications protocol used to connect to Web servers on the Internet or on a local network (intranet).

Being a part of the Internet Protocol suite, it defines the commands and services used for transmitting webpage data.

How does HTTP Work ?

HTTP functions as a request — response protocol. Giving an example , a web browser can be a client and the server can be the application running on a computer hosting a website. An HTTP request message is sent by the client to the server. Resources are provided by the server such as HTML files or any other data, or other function of client are also performed, returning a response message to the client. Completion status information about the request and content requested is present in the response message.

Have used mail ? Let’s talk on the protocol associated with it…

Simple Mail Transfer Protocol (SMTP)

SMTP is a set of commands that authenticate and direct the transfer of electronic mail

Protocol for sending e-mail over the internet is called as the SMTP. E-mail client such as Gmail, Outlook etc. uses SMTP.

How does SMTP Work ?

A TCP connection is opened by the client who wants to send the mail to the SMTP server which is then sent across the connection. The SMTP is in listening mode by default. As soon as the SMTP detects a TCP connection from the client a SMTP process connection is initiated on that port. A mail is sent as soon as a successfully establishing the TCP connection.

Learnt a lot about communication protocols…

In a Nut-shell

After knowing about communication protocols and their types we can say that every communication protocol has got it’s own significance and application in technical domain. Giving an example, SMTP is used for transfer of mail, HTTP is used for creating a connection between web servers and local network, FTP for file transfer and so on…