Layered Network Architecture

The main aim of the layered architecture is to divide the design into small pieces.

• Each lower layer adds its services to the higher layer to provide a full set of services to manage communications and run the applications.
• It provides modularity and clear interfaces, i.e., provides interaction between subsystems.
• It ensures the independence between layers by providing the services from lower to higher layer without defining how the services are implemented. Therefore, any modification in a layer will not affect the other layers.
• The number of layers, functions, contents of each layer will vary from network to network. However, the purpose of each layer is to provide the service from lower to a higher layer and hiding the details from the layers of how the services are implemented.
• The basic elements of layered architecture are services, protocols, and interfaces.
• Service: It is a set of actions that a layer provides to the higher layer.
• Protocol: It defines a set of rules that a layer uses to exchange the information with peer entity. These rules mainly concern about both the contents and order of the messages used.
• Interface: It is a way through which the message is transferred from one layer to another layer.
• In a layer n architecture, layer n on one machine will have a communication with the layer n on another machine and the rules used in a conversation are known as a layer-n protocol.