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| In [[computer science]] a '''protocol''' is a complete [[specification]] of the rules for [[communication]] between two or more computing devices in a [[computer network]]. What is commonly referred to as a protocol is generally a [[stack]] of specifications, each building upon the others to define all aspects of communication. | | {{subpages}} |
| | In [[computer science]], a '''protocol''' is a specification of the rules for communication among devices across a network. Protocols have a wide range in complexity. On one end of the spectrum, the [[electrical]] characteristics of ones and zeros within a particular [[digital logic family]] might be considered a protocol. Similarly, the sequence of modulated [[infrared light]] emitted by a [[television]] remote control is also a protocol. A more complicated example of a protocol is the set or "stack" of protocols used in [[computer networking reference models]], such as the [[Internet Protocol Suite]] or [[Open Systems Interconnection Reference Model]]. |
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| Protocols have a wide range in complexity. On one end of the spectrum, the [[electrical]] characteristics of ones and zeros within a particular [[digital logic family]] might be considered a protocol. Similarly, the sequence of modulated [[infrared light]] emitted by a [[television]] remote control is also a protocol. A more complicated example of a protocol is the [[TCP/IP|Transfer Control Protocol over Internet Protocol]] used extensively in the [[internet]], or even higher level protocols built on top of TCP/IP.
| | ==References== |
| | {{reflist}} |
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| == A stack of protocols ==
| | [[Category:Reviewed Passed]] |
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| ''Main article:'' [[OSI model]]
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| The [[open systems interconnection|Open Systems Interconnection]] initiative suggests a seven-layer model to define a protocol. In their model, a protocol is defined (from lowest to highest level):
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| # [[physical layer (OSI Model)|Physical Layer]] -- Defines [[electrical]] and/or [[physical]] specifications for the communications. For instance, it may specify [[disjoint]] [[voltage]] ranges for binary ones or zeros. This layer would also specify things such as [[baud rate]], [[termination (transmission lines)|transmission line termination]], and many other things.
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| # [[data link layer (OSI Model)|Data Link Layer]] -- Defines for communications between two [[adjacent]] (i.e. directly connected) devices. Specifies things such as how packets are framed, and how to detect and correct errors which occur in the physical layer.
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| # [[network layer (OSI Model)|Network Layer]] -- Defines how individual communications can be [[route (networking)|routed]] between non-adjacent devices. This is only necessary if more than two devices need to communicate (i.e. a [[network]]).
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| # [[transport layer (OSI Model)|Transport Layer]] -- Defines further abstractions to the network layer, hiding implementation details such as network congestion or maximum frame sizes.
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| # [[session layer (OSI Model)|Session Layer]] -- Defines further abstractions to the transport layer, yielding the illusion that each channel of communications is a continuous [[stream]] of information instead of discrete frames or packets.
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| # [[presentation layer (OSI Model)|Presentation Layer]] -- Defines conventions for representing common types of information. For instance, [[ASCII]] is a convention which specifies, among other things, how to represent each letter of the alphabet as an integer, in a [[operating system|platform-]] and [[computer architecture|architecture-]] independent manner. Under this definition, any [[file format]] could be considered a presentation layer, if that file format were integral to the operation of the protocol.
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| # [[application layer (OSI Model)|Application Layer]] -- Defines application specific uses for the network. Common examples of this are [[HTTP]] or [[FTP]].
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| == List of protocols ==
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| # [[File Tranfer Protocol]] (FTP) - Application Layer 7
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| # [[Hypertext Tranfer Protocol]] (HTTP) - Application Layer 7
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| # [[Simple Mail Transfer Protocol]](SMTP) - Application Layer 7
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| # [[Transmission Control Protocol]] (TCP) - Network Layer 3
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| # [[Internet Control Message Protocol]] (ICMP)
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| # [[Internet Protocol]] (IP) - Data Link Layer 2
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| # [[Ethernet]] - Physical Layer 1
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| # [[802.11a/b/g/n]] (Wi-Fi, in its various incarnations)
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| # [[Bluetooth]] (cf. IEEE 802.15)
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| # [[802.16]] (Wi-Max)
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| # [[General Packet Radio Service]] (GPRS)
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| And many, many more.
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| [[Category:CZ Live]]
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| [[Category:Computers Workgroup]] | |
