Skip to main content

OSI model Contents Description of OSI layers | References | Navigation menu

Networks


computer networkingabstractioncommunication protocolsnetworkWeb browser• Electronic mailcommunication.encryptionfirewallframesError detection and correctionelectricalfiber-optic cablesEthernetfiber opticDSLcoaxial cablebroadbandwirelessbit












OSI model




From Wikipedia, the free encyclopedia






Jump to navigation
Jump to search


The Open Systems Interconnection model (OSI model) is a method of thinking of computer networking in terms of abstraction layers. Different communication protocols with similar functions are grouped into different logical layers on the OSI Model. Each layer of the OSI Model makes use of functions provided by the layers below it and provides functions that are used by the layers above it.
There are 7 layers. kn






Contents





  • 1 Description of OSI layers

    • 1.1 Layer 7: Application layer


    • 1.2 Layer 6: Presentation layer


    • 1.3 Layer 5: Session layer


    • 1.4 Layer 4: Transport layer


    • 1.5 Layer 3: Network layer


    • 1.6 Layer 2: Data link layer


    • 1.7 Layer 1: Physical layer



  • 2 References




Description of OSI layers |


According to the standard OSI Model there are seven layers. Each layer is dependent upon the layers below it to function.





















OSI Model

Data unit
Layer
Host
layers
7. Application

Network process to computer programs
6. Presentation

Data representation, security encryption, convert computer code to network formatted code
5. Session

Interhost communication, managing sessions between programs
4. Transport

End-to-end connections, reliability and flow control
Media
layers
3. Network

Path determination and logical addressing
2. Data link

Physical addressing
1. Physical

The physical infrastructure used to send and receive signals

Some aspects of computer networking, such as management and security, use or are used on every layer.



Layer 7: Application layer |

The application layer provides an interface for the end user operating a device connected to a network. This layer is what the user sees, in terms of loading an application (such as Web browser or e-mail); that is, this application layer is the data the user views while using these applications. Examples of application layer functionality include:


• Support for file transfers


• Ability to print on a network


• Electronic mail


• Electronic messaging


• Browsing the World Wide Web.



Layer 6: Presentation layer |


To be able to properly interpret a message sent through the network this layer is responsible for the proper translation or interpretation.



Layer 5: Session layer |


This layer establishes request/response communication. When needed a session is started with authentication, after which a request is sent. After a response the session might be ended or a new request is sent. This is the first layer where a client/server concept is introduced. Where a specific device might change the role from client to server or vice versa.



Layer 4: Transport layer |


The Transport Layer is the level at which system reliability and quality are ensured. This layer manages traffic flow through the network layer to reduce congestion on a network, and performs error checking ensuring quality of service by resending data when data has been corrupted. Some of the most popular methods of encryption and firewall security take place on this layer.



Layer 3: Network layer |


The Routing Layer works to coordinate related parts of a data conversation to ensure that large files are transferred. In other words, while the data link layer deals with the method in which the physical layer is used to transfer data, the network layer deals with organizing that data for transfer and reassembly. This layer also handles aspects of Routing Protocols, finding the available [best] path(s) from one network to another to ensure delivery of the data.



Layer 2: Data link layer |


The Data Layer is mainly the method in which information from the network is broken down into frames and transmitted over the physical layer. This layer is also responsible for some Error detection and correction and some addressing so different devices can tell each other apart in larger systems.



Layer 1: Physical layer |


The physical layer refers to electrical and physical aspects of devices. In particular, it specifies how a device sends and receives information, such as using copper wires or fiber-optic cables. Examples of this include Ethernet or fiber optic cables, phone cords used for dial-up or DSL services, the coaxial cable used to provide broadband internet, the wires used to connect various components of a computer or even the radio signals used in wireless communication. Other functions of the physical layer include the conversion of signals into something that another layer can use (referred to as a bit), and adjusting the signal to allow for multiple users to use the same connections.



References |











Retrieved from "https://simple.wikipedia.org/w/index.php?title=OSI_model&oldid=6565283"













Navigation menu


























(RLQ=window.RLQ||[]).push(function()mw.config.set("wgPageParseReport":"limitreport":"cputime":"0.028","walltime":"0.036","ppvisitednodes":"value":116,"limit":1000000,"ppgeneratednodes":"value":0,"limit":1500000,"postexpandincludesize":"value":311,"limit":2097152,"templateargumentsize":"value":73,"limit":2097152,"expansiondepth":"value":8,"limit":40,"expensivefunctioncount":"value":0,"limit":500,"unstrip-depth":"value":0,"limit":20,"unstrip-size":"value":0,"limit":5000000,"entityaccesscount":"value":0,"limit":400,"timingprofile":["100.00% 20.945 1 -total","100.00% 20.945 1 Template:Reflist"," 15.14% 3.172 1 Template:Main_other"],"scribunto":"limitreport-timeusage":"value":"0.002","limit":"10.000","limitreport-memusage":"value":523380,"limit":52428800,"cachereport":"origin":"mw1270","timestamp":"20190725130544","ttl":2592000,"transientcontent":false););"@context":"https://schema.org","@type":"Article","name":"OSI model","url":"https://simple.wikipedia.org/wiki/OSI_model","sameAs":"http://www.wikidata.org/entity/Q93312","mainEntity":"http://www.wikidata.org/entity/Q93312","author":"@type":"Organization","name":"Contributors to Wikimedia projects","publisher":"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":"@type":"ImageObject","url":"https://www.wikimedia.org/static/images/wmf-hor-googpub.png","datePublished":"2010-03-22T12:04:19Z","dateModified":"2019-06-04T09:51:40Z","headline":"model with 7 layers to describe communication systems"(RLQ=window.RLQ||[]).push(function()mw.config.set("wgBackendResponseTime":99,"wgHostname":"mw1269"););

Popular posts from this blog

Canceling a color specificationRandomly assigning color to Graphics3D objects?Default color for Filling in Mathematica 9Coloring specific elements of sets with a prime modified order in an array plotHow to pick a color differing significantly from the colors already in a given color list?Detection of the text colorColor numbers based on their valueCan color schemes for use with ColorData include opacity specification?My dynamic color schemes

Invision Community Contents History See also References External links Navigation menuProprietaryinvisioncommunity.comIPS Community ForumsIPS Community Forumsthis blog entry"License Changes, IP.Board 3.4, and the Future""Interview -- Matt Mecham of Ibforums""CEO Invision Power Board, Matt Mecham Is a Liar, Thief!"IPB License Explanation 1.3, 1.3.1, 2.0, and 2.1ArchivedSecurity Fixes, Updates And Enhancements For IPB 1.3.1Archived"New Demo Accounts - Invision Power Services"the original"New Default Skin"the original"Invision Power Board 3.0.0 and Applications Released"the original"Archived copy"the original"Perpetual licenses being done away with""Release Notes - Invision Power Services""Introducing: IPS Community Suite 4!"Invision Community Release Notes

199年 目錄 大件事 到箇年出世嗰人 到箇年死嗰人 節慶、風俗習慣 導覽選單