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protocol stack - technical definition

A conceptual organization of protocol groupings into a vertical stack. In such a stack, the lowest level protocols are placed at the bottom, forming the foundation upon which higher levels, or layers, are placed.The OSI Reference Model, for example, comprises seven layers, each of which is interrelated, providing services to those above and below.The lowest is Layer 1, the Physical Layer, which contains specifications for the electrical, optical, and mechanical aspects of the interface of the device to a physical transmission medium, such as twisted pair, coax, or fiber. The highest is Layer 7, the Application Layer, which contains specifications for services that support user and application tasks such as file transfer, interpretation of graphic formats and documents, and document processing. See also OSI Reference Model and protocol suite.

See protocol stack in Webster''s New World Hacker Dictionary

In networking, protocols are layered on top of each other, with each layer being responsible for a different aspect of communication. A protocol stack is a particular software implementation of a computer network protocol suite. The suite consists of the protocol definitions, whereas the stack is the software implementation.

Protocols within a suite are designed with a very specific purpose, and each protocol typically communicates with two others in the stack. The lowest protocol deals with the low-level physical interaction of hardware, whereas user applications deal with only the uppermost layers. Protocol stacks are generally divided into three parts dealing with applications, transport, and media.

See Also: Encapsulation; Network; OSI-Model; Protocol.

Wikipedia. Protocol Stack. [Online, May 5, 2005.] Wikipedia Website. http://en.wikipedia.org/wiki/Protocol_stack.

See protocol stack in Computer

The set of protocols used in a communications network. A protocol stack is a prescribed hierarchy of software layers, starting from the application layer at the top (the source of the data being sent) to the data link layer at the bottom (transmitting the bits on the wire). The stack resides in each client and server, and the layered approach lets different protocols be swapped in and out to accommodate different network architectures. For more details about each layer, see OSI model.

The Protocol Stack

Using TCP/IP as a model, the sending application hands data to the transport layer, which breaks it up into the packets required by the network. It stores the sequence number and other data in its header. The network layer adds source and destination data in its header, and the data link layer adds station data in its header. On the other side, the corresponding layer reads and processes the headers and discards them.

Headers Come and Go

Headers are added at each layer in the stack of the sending machine and discarded at the receiving end by their counterpart layer. The headers serve only to get the message body from one point to another.

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