What is a protocol?
Abstract definition:
A protocol defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.
Let’s break it down with an analogy.
Example 1: Protocols Applied in Human Interaction - Water Cooler
Protocols are quite common.
In Australia, the Monday morning water-cooling protocol is as follows:
Colleague: How’s it going?
Boss: Good. You?
Colleague: Did you watch the footy?
Boss: Yes. How good were the Hawks?
Colleague: Very good. Smashed the Dees.
Boss: Get back to work.
Colleague: Yessir.
Boss: Good bye.
This is a standard protocol.
Note: there is an introduction, then an exchange of information. Questions, then answers. Then finally, a termination.
Example 2: Protocols Applied in Human Interaction - The Nerd Dating Protocol
Boy: Hi. My name is –
Girl: Bye
A very simple one.
This example is analogous to a protocol - the TCP protocol: there was a TCP connection request, and the connection response was brutally rebuffed. There are may others.
So why do we need protocols?
We need protocols - rules in order to: (i) communicate, and (ii) do so effectively.
You use them everyday without realising: it applies in everything e.g. when we send letters: we need to write the address on an envelope - the address must be agreed upon, as must the language, as well as the written characters. We pack a certain amount content in a letter. We might even ask if the address is deliverable.
Protocols when computers communicate with each other applies in much the same way it applies to human beings.