What exactly is a network layer, and what is its importance to the network? Also please explain the significance of the layer numbers.
In computer programming, layering is the organization of programming into separate functional components that interact in some sequential and hierarchical way, with each layer usually having an interface only to the layer above it and the layer below it.
Communication programs are often layered. The reference model for communication programs, Open System Interconnection (OSI), is a layered set of protocols in which programming at both ends of a communications exchange uses an identical set of layers. In the OSI model, there are seven layers, each reflecting a different function that has to be performed in order for program-to-program communication to take place between computers.
TCP/IP is an example of a two-layer (TCP and IP) set of programs that provide transport and network address functions for Internet communication. A set of TCP/IP and other layered programs is sometimes referred to as a protocol stack.
For details about the entire OSI model and all the numbered layers, see our complete definition page.
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