Prerequisite – Layers of OSI Model, Working of ISO-OSI Model
A protocol is simply defined as a set of rules and regulations for data communication. Rules are basically defined for each and every step and process at time of communication among two or more computers. Networks are needed to follow these protocols to transmit data successfully. All protocols might be implemented using hardware, software, or combination of both of them. There are three aspects of protocols given below :
- Syntax –
It is used to explain data format that is needed to be sent or received.
- Semantics –
It is used to explain exact meaning of each of sections of bits that are usually transferred.
- Timings –
It is used to explain exact time at which data is generally transferred along with speed at which it is transferred.
Protocol Hierarchies :
Generally, Computer networks are comprised of or contain a large number of pieces of hardware and software. To just simplify network design, various networks are organized and arranged as a stack of layers of hardware and software, one on top of another. The number, name, content, and function of each layer might vary and can be different from one network to another. The main purpose of each of layers is just to offer and provide services to higher layers that are present. Each and every layer has some particular task or function. In programming, this concept is very common. The networks are organized and arranged as different layers or levels simply to reduce and minimize complexity of design of network software.
Below is diagram representing a five-layer network. The diagram shows communication between Host 1 and Host 2. The data stream is passed through a number of layers from one host to other. Virtual communication is represented using dotted lines between peer layers. Physical communication is represented using solid arrows between adjacent layers. Through physical medium, actual communication occurs. The layers at same level are commonly known as peers. The peer basically has a set of communication protocols. An interface is present between each of layers that are used to explain services provided by lower layer to higher layer.
- The layers generally reduce complexity of communication between networks
- It increases network lifetime.
- It also uses energy efficiently.
- It does not require overall knowledge and understanding of network.