Answer:
Protocol: It is a set of rules that govern communication over electronic devices. It is bridge between two devices to communicate with each other. All layers of OSI model support some protocol features of communication between devices over internet.
Explanation:
What is the Protocol
A protocol is a set of rules that govern communication over electronic devices that how to communicate with each other. These sets of rules include how to send data, what type of data may be transmitted, and how to receive the data and how to confirm that, data has been transmitted successfully.
You can think about protocol as a spoken language between two people. Therefore, people can understand their language easily if both know its rules and vocabulary. That means, if both people can speak with each other in the same language then they can communicate effectively with each other.
Similarly, if two devices support the same protocol, regardless of the type of device or manufacturers, they can communicate with each other effectively. For example, an android device can send email to an iPhone device using a standard mail protocol.
Today different Protocols exist for several different applications. For example wired networking (e.g. Ethernet), wireless networking (e.g. 802.11ac) and internet communication (e.g. IP).
The Internet protocol contains dozens of protocol which is used for transmitting data over the Internet. The protocol may be broken into four categories.
1. Link layer
2. Internet layer
3. Transport layer
4. Application layer
<u>OSI Model and Its Layers</u>
The Open System Interconnection (OSI) model is a conceptual model that is created by the International Organization for Standardization (ISO) which uses a standard protocol to enable communication between devices. In short, the OSI model provides a standard of communication between different computer systems. It has 7 layers, each layer has its own functionality as described below:
- Physical layer: Transmits raw bitstream over the physical medium
- Data link layer: Define the format of data on the network
- Network layer: Decide which physical path the data will take
- Transport layer: Transmit data using transmission protocols including UDP and TCP
- Session layer: Maintains connections and is responsible for controlling sessions and ports
- Presentation layer: Ensure that data is in a usable format and is where data encryption occur
- Application layer: Human-computer-interaction layer, where the application can access the network services
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