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The '''Open Systems Interconnection Basic Reference Model''' (OSI Reference Model or '''OSI Model''') is an abstract description for layered communications and computer [[network protocol]] design. It was developed as part of the [[Open Systems Interconnection]] (OSI) initiative<ref>reference needed</ref>. In its most basic form, it divides network architecture into seven layers which, from top to bottom, are the Application, Presentation, Session, Transport, Network, Data-Link, and Physical Layers. It is therefore often referred to as the '''OSI Seven Layer Model'''.

A layer is a collection of conceptually similar functions that provide services to the layer above it and receives service from the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of the path.

Even though it has been largely superseded by newer [[IETF]], [[IEEE]], and indeed OSI protocol developments (subsequent to the publication of the original architectural standards), the basic OSI model is considered an excellent place to begin the study of network architecture. Not understanding that the pure seven-layer model is more historic than current, many beginners make the mistake of trying to fit every protocol under study into one of the seven basic layers. Especially the attempts of [[cross-layer optimization]] break the boundaries of the original layer scheme. Describing the actual layer concept with implemented systems is not always easy to do as most of the protocols in use on the [[Internet]] were designed as part of the [[TCP/IP model]], and may not fit cleanly into the OSI Model.

== History ==
In 1977, work on a layered model of network architecture was started, and the [[International Organization for Standardization]] (ISO) began to develop its OSI framework architecture. The ISO is a worldwide federation of national standards bodies from some 130 countries, one from each country.{{Fact|date=June 2008}}
OSI has two major components: an abstract model of networking (the Basic Reference Model, or seven-layer model) and a set of specific protocols. The standard documents that describe the OSI model can be freely downloaded from the ITU-T as the '''X.200'''-series of recommendations <ref>[http://www.itu.int/rec/T-REC-X/en ITU-T X-Series Recommendations].</ref>. A number of the protocol specifications are also available as part of the ITU-T X series. The equivalent ISO and ISO/IEC standards for the OSI model are available from the ISO, but only some of the ISO/IEC standards are available as cost-free downloads.<ref>[http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html Publicly Available Standards<!-- Bot generated title -->]</ref>

Some aspects of OSI design evolved from experiences with the [[CYCLADES]] network, which also influenced Internet design. The new design was documented in ISO 7498 and its various addenda. In this model, a networking system is divided into layers. Within each layer, one or more entities implement its functionality. Each entity interacts directly only with the layer immediately beneath it, and provides facilities for use by the layer above it.

Protocols enable an entity in one host to interact with a corresponding entity at the same layer in another host. Service definitions abstractly describe the functionality provided to an (N)-layer by an (N-1) layer, where N is one of the seven layers of protocols operating in the local host.

== Description of OSI layers ==
{|class="wikitable" align="right"
! colspan="4" | OSI Model
|-
|-
|{{ThisDateInRecentYears|Month=September|Day=3}} <!-- preserves autoscroll -->
!
!Data unit
!Layer
!style="width:9em;"|Function
|-
!rowspan="4"|Host<br />layers
|rowspan="3"|Data
|7. [[Application Layer|Application]]
|<small>Network process to application</small>
|-
|6. [[Presentation Layer|Presentation]]
|<small>Data representation and encryption</small>
|-
|5. [[Session Layer|Session]]
|<small>Interhost communication</small>
|-
|Segment/Datagram
|4. [[Transport Layer|Transport]]
|<small>End-to-end connections and reliability</small>
|-
!rowspan="3"|Media<br />layers
|Packet
|3. [[Network Layer|Network]]
|<small>Path determination and [[logical address]]ing</small>
|-
|Frame
|2. [[Data Link Layer|Data Link]]
|<small>Physical addressing (MAC & LLC)</small>
|-
|Bit
|1. [[Physical Layer|Physical]]
|<small>Media, signal and binary transmission</small>
|}
|}
{{Day}}


==Events==
=== Layer 7: Application Layer ===
*[[36 BC]] - In the [[Battle of Naulochus]], [[Marcus Vipsanius Agrippa]], [[admiral]] of [[Caesar Augustus|Octavian]], defeats [[Sextus Pompeius]], son of [[Pompey]], thus ending [[Pompeian]] resistance to the [[Second Triumvirate]].
{{main | Application Layer}}
* [[301]] - [[San Marino]], one of the [[List of countries by area|smallest nations in the world]] and the world's oldest [[republic]] still in existence, is founded by [[Saint Marinus]].
The application layer is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. Such application programs fall outside the scope of the OSI model. Application layer functions typically include identifying communication partners, determining resource availability, and synchronizing communication. When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit. When determining resource availability, the application layer must decide whether sufficient network resources for the requested communication exist. In synchronizing communication, all communication between applications requires cooperation that is managed by the application layer. Some examples of application layer implementations include Telnet, File Transfer Protocol (FTP), and Simple Mail Transfer Protocol (SMTP).
*[[1189]] - [[Richard I of England]] (a.k.a. Richard "the Lionheart") is crowned at [[Westminster]].

*[[1260]] - The [[Mamluks]] defeat the [[Mongols]] at the [[Battle of Ain Jalut]] in [[Palestine (region)|Palestine]], marking their first decisive defeat and the point of maximum expansion of the [[Mongol Empire]].
=== Layer 6: Presentation Layer ===
*[[1650]] - [[Third English Civil War]]: [[Battle of Dunbar (1650)]]
{{main | Presentation Layer}}
*[[1651]] - [[Third English Civil War]]: [[Battle of Worcester]] - [[Charles II of England]] is defeated in the last main battle of the war.
The [[Presentation Layer]] establishes a context between Application Layer entities, in which the higher-layer entities can use different syntax and semantics, as long as the Presentation Service understands both and the mapping between them. The presentation service data units are then encapsulated into Session Protocol Data Units, and moved down the stack.
*[[1666]] - The Royal Exchange burnt down in the [[Great Fire of London]]

*[[1777]] - [[Cooch's Bridge]] - Skirmish of [[American Revolution]]ary war in [[New Castle County, Delaware|New Castle County]], [[Delaware]] where the [[Flag of the United States]] was flown in battle for the first time.
The original presentation structure used the Basic Encoding Rules of [[Abstract Syntax Notation One]] (ASN.1), with capabilities such as converting an [[EBCDIC]]-coded text [[Computer file|file]] to an [[ASCII]]-coded file, or [[Serialization|serializing]] [[object (computer science)|objects]] and other [[data structure]]s into and out of [[XML]]. ASN.1 has a set of cryptographic encoding rules that allows end-to-end encryption between application entities.
*[[1783]] - [[American Revolutionary War]]: The war ends with the signing of the [[Treaty of Paris (1783)|Treaty of Paris]] by the [[United States]] and the [[Kingdom of Great Britain]]. [[United Sates|America]] is officially free from [[Kingdom of Great Britain|Britain]]

*[[1798]] - Weeklong battle of [[St. George's Caye]] begun between [[Spain|Spanish]] and [[Kingdom of Great Britain|British]] off the coast of [[Belize]].
===Layer 5: Session Layer===
*[[1803]] - [[England|English]] scientist [[John Dalton]] started using symbols to represent the atoms of different elements.
{{main | Session Layer}}
*[[1838]] - Dressed in a sailor's uniform and carrying identification papers provided by a [[Freedman|Free Black]] seaman, future [[abolitionist]] [[Frederick Douglass]] boards a train in [[Maryland]] on his way to freedom from [[slavery]].
The [[Session Layer]] controls the dialogues/connections (sessions) between computers. It establishes, manages and terminates the connections between the local and remote application. It provides for [[Duplex (telecommunications)|full-duplex]], [[half-duplex]], or [[Simplex communication|simplex]] operation, and establishes checkpointing, adjournment, termination, and restart procedures. The OSI model made this layer responsible for "graceful close" of sessions, which is a property of [[Transmission Control Protocol|TCP]], and also for session checkpointing and recovery, which is not usually used in the Internet Protocol Suite. The Session Layer is commonly implemented explicitly in application environments that use remote procedure calls (RPCs).
*[[1855]] - [[Indian Wars]]: In [[Nebraska]], 700 soldiers under [[United States|American]] [[General]] [[William S. Harney]] avenge the [[Grattan Massacre]] by attacking a [[Sioux]] village, killing 100 men, women, and children.

*[[1861]] - [[American Civil War]]: [[Confederate States of America|Confederate]] [[General]] [[Leonidas Polk]] invades neutral [[Kentucky]], prompting the state legislature to ask for [[United States|Union]] assistance.
=== Layer 4: Transport Layer ===
*[[1870]] - [[Franco-Prussian War]]: the [[Siege of Metz]] begins, which will result in a decisive [[Kingdom of Prussia|Prussian]] victory on [[October 23]].
{{main | Transport Layer}}
*[[1874]] - The congress of the [[state]] of [[Mexico (state)|México]] elevates [[Naucalpan]] to the category of [[Villa]], with the title of "Villa de [[Benito Juárez|Juárez]]".
The [[Transport Layer]] provides transparent transfer of [[data]] between end users, providing reliable data transfer services to the upper layers. The Transport Layer controls the reliability of a given link through flow control, segmentation/desegmentation, and error control. Some protocols are state and connection oriented. This means that the Transport Layer can keep track of the segments and retransmit those that fail.
*[[1878]] - Over 640 die when the crowded pleasure boat {{SS|Princess Alice|1865|2}} collides with the ''[[Bywell Castle]]'' in the [[River Thames]].

* 1914 - [[William, Prince of Albania]] leaves the country after just six months due to opposition to his rule.
Although not developed under the OSI Reference Model and not strictly conforming to the OSI definition of the Transport Layer, the best known examples of a Layer 4 protocol are the [[Transmission Control Protocol]] (TCP) and [[User Datagram Protocol]] (UDP).
*[[1929]] - [[Dow Jones Industrial Average]] reached all time high at the time (381.17), which was shortly followed by the [[Crash of 1929]].

*[[1933]] - [[Yevgeniy Abalakov]] reaches the highest point of the [[Soviet Union]] - [[Communism Peak]] (7495 m).
Of the actual OSI protocols, there are five classes of transport protocols ranging from class 0 (which is also known as '''TP0''' and provides the least error recovery) to class 4 (which is also known as '''TP4''' and is designed for less reliable networks, similar to the Internet). Class 0 is closest to UDP. Class 4 is closest to TCP, although TCP contains functions, such as the graceful close, which OSI assigns to the Session Layer. Detailed characteristics of TP0-4 classes are shown in the following table:<ref>{{cite web
*[[1935]] - [[Sir]] [[Malcolm Campbell]] reaches 304.331 [[miles per hour]] on the [[Bonneville Salt Flats]] in [[Utah]], becoming the first person to drive an [[automobile]] over 300 mph
| title = ITU-T Recommendation X.224 (11/1993) [ISO/IEC 8073]
*[[1939]] - [[World War II]] begins when [[France]], the [[United Kingdom]], [[New Zealand]], and [[Australia]] declare war on [[Germany]] after the [[invasion of Poland]], starting the [[Allies of World War II|Allies]].
| url = http://www.itu.int/rec/T-REC-X.224-199311-I/en/
*[[1942]] - [[World War II]]: Uprising of the [[Jewish]] [[ghetto]] in [[Lakhva]] occurs.
| accessdate = 2008-06-18}}</ref>
*[[1943]] - [[World War II]]: Mainland [[Italy]] is invaded by [[Allies|Allied]] forces for the first time in the war.

*[[1944]] - [[Holocaust]]: [[Diarist]] [[Anne Frank]] and her family are placed on the last transport train from [[Westerbork]] to [[Auschwitz]], arriving three days later.
{| class="wikitable"
*[[1950]] - [[Giuseppe Farina|"Nino" Farina]] becomes the first [[List of Formula One World Drivers' Champions|Formula One Drivers' champion]] after winning the [[1950 Italian Grand Prix]].
|-
*[[1951]] - The first long-running American television [[soap opera]], ''[[Search for Tomorrow]]'', airs its first episode on the [[CBS]] network.
! Feature Name
*[[1954]] - The [[People's Liberation Army]] begin shelling the [[Republic of China|ROC]]-controlled islands of [[Quemoy]].
! TP0
* 1954 - The [[Germany|German]] [[U-Boat]] [[U-505]] began its move from a specially constructed dock to its final site at [[Chicago's]] [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]].
! TP1
*[[1967]] - [[Dagen H]] in [[Sweden]]: traffic changes from driving on the left to driving on the right overnight
! TP2
*[[1971]] - [[Qatar]] becomes an independent state
! TP3
*[[1976]] - [[Viking program]]: The [[Viking 2]] spacecraft lands at [[Utopia Planitia]] on [[Mars (planet)|Mars]].
! TP4
*[[1994]] - [[Sino-Soviet Split]]: [[Russia]] and the [[People's Republic of China]] agree to de-target their [[nuclear weapon]]s against each other.
|-
*[[1995]] - [[eBay]] founded.
| Connection oriented
*[[1997]] - A [[Vietnam Airlines]] [[Tupolev]] [[TU-134]] crashes on approach into [[Phnom Penh]] airport, killing 64.
| -
*[[2004]] - The [[Beslan school massacre]] ends in the deaths of approximately 344 people, mostly teachers and children.
| -
| -
| {{Yes}}
| {{Yes}}
|-
| Connectionless
| -
| -
| -
| {{No}}
| {{Yes}}
|-
| Segmentation/Fragmentation
| {{Yes}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
|-
| Reassembly
| {{Yes}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
|-
| Error Recovery
| {{No}}
| {{Yes}}
| {{No}}
| {{No}}
| {{Yes}}
|-
| Reinitiate connection (if an excessive number of [[Protocol_data_unit|PDUs]] are unacknowledged)
| {{No}}
| {{Yes}}
| {{No}}
| {{Yes}}
| {{Yes}}
|-
| multiplexing and demultiplexing over a single [[virtual circuit]]
| {{No}}
| {{No}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
|-
| Reliable Transport Service
| {{No}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
| {{Yes}}
|}

Perhaps an easy way to visualize the Transport Layer is to compare it with a Post Office, which deals with the dispatch and classification of mail and parcels sent. Do remember, however, that a post office manages the outer envelope of mail. Higher layers may have the equivalent of double envelopes, such as cryptographic presentation services that can be read by the addressee only. Roughly speaking, [[Tunneling protocol|tunneling protocols]] operate at the Transport Layer, such as carrying non-IP protocols such as [[IBM]]'s [[IBM Systems Network Architecture|SNA]] or [[Novell]]'s [[Internetwork Packet Exchange|IPX]] over an IP network, or end-to-end encryption with [[IPsec]]. While [[Generic Routing Encapsulation]] (GRE) might seem to be a Network Layer protocol, if the encapsulation of the payload takes place only at endpoint, GRE becomes closer to a transport protocol that uses IP headers but contains complete frames or packets to deliver to an endpoint. [[Layer 2 Tunneling Protocol|L2TP]] carries [[Point-to-Point Protocol|PPP]] frames inside transport packet.

=== Layer 3: Network Layer ===
{{main | Network Layer}}
The [[Network Layer]] provides the functional and procedural means of transferring variable length [[data]] sequences from a source to a destination via one or more networks, while maintaining the [[quality of service]] requested by the Transport Layer. The Network Layer performs network [[routing]] functions, and might also perform fragmentation and reassembly, and report delivery errors. [[Router]]s operate at this layer—sending data throughout the extended network and making the Internet possible. This is a logical addressing scheme – values are chosen by the network engineer. The addressing scheme is hierarchical.

<!-- STRANGE THAT A PROTOCOL THAT DOESN'T ACUTALLY BELONG TO THE OSI MODEL IS ITS BEST KNOWN EXAMPLE, WHY NOT DISCUSS OSI ON ITS OWN MERITS? -->The best-known example of a Layer 3 protocol is the [[Internet Protocol]] (IP). It manages the [[Connectionless protocol | connectionless]] transfer of data one hop at a time, from end system to ingress router, router to router, and from egress router to destination end system. It is not responsible for reliable delivery to a next hop, but only for the detection of errored packets so they may be discarded. When the medium of the next hop cannot accept a packet in its current length, IP is responsible for '''fragmenting''' into sufficiently small packets that the medium can accept it.

A number of layer management protocols, a function defined in the Management Annex, ISO 7498/4, belong to the Network Layer. These include routing protocols, multicast group management, Network Layer information and error, and Network Layer address assignment. It is the function of the payload that makes these belong to the Network Layer, not the protocol that carries them.

=== Layer 2: Data Link Layer ===
{{main | Data Link Layer}}
The [[Data Link Layer]] provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the Physical Layer. Originally, this layer was intended for point-to-point and point-to-multipoint media, characteristic of wide area media in the telephone system. Local area network architecture, which included broadcast-capable multiaccess media, was developed independently of the ISO work, in [[IEEE 802 |IEEE Project 802]]. IEEE work assumed sublayering and management functions not required for WAN use. In modern practice, only error detection, not flow control using sliding window, is present in modern data link protocols such as [[Point-to-Point Protocol]] (PPP), and, on local area networks, the IEEE 802.2 LLC layer is not used for most protocols on Ethernet, and, on other local area networks, its flow control and acknowledgment mechanisms are rarely used. Sliding window flow control and acknowledgment is used at the Transport Layer by protocols such as [[Transmission Control Protocol|TCP]], but is still used in niches where [[X.25]] offers performance advantages.

Both WAN and LAN services arrange bits, from the Physical Layer, into logical sequences called frames. Not all Physical Layer bits necessarily go into frames, as some of these bits are purely intended for Physical Layer functions. For example, every fifth bit of the [[FDDI]] bit stream is not used by the Data Link Layer.

==== WAN Protocol architecture ====
[[Connection-oriented]] WAN data link protocols, in addition to framing, detect and may correct errors. They also are capable of controlling the rate of transmission. A WAN Data Link Layer might implement a [[sliding window]] flow control and acknowledgment mechanism to provide reliable delivery of frames; that is the case for [[Synchronous Data Link Control|SDLC]] and [[HDLC]], and derivatives of HDLC such as [[LAPB]] and [[Link Access Procedures, D channel|LAPD]].

==== IEEE 802 LAN architecture ====
Practical, [[connectionless]] LANs began with the pre-IEEE [[Ethernet]] specification, which is the ancestor of [[IEEE 802.3]]. This layer manages the interaction of devices with a shared medium, which is the function of a [[Media Access Control]] sublayer. Above this MAC sublayer is the media-independent [[IEEE 802.2]] [[Logical Link Control]] (LLC) sublayer, which deals with addressing and multiplexing on multiaccess media.

While IEEE 802.3 is the dominant wired LAN protocol and [[IEEE 802.11]] the wireless LAN protocol, obsolescent MAC layers include [[Token Ring]] and [[FDDI]]. The MAC sublayer detects but does not correct errors.

=== Layer 1: Physical Layer ===
{{main | Physical Layer}}
The [[Physical Layer]] defines all the electrical and physical specifications for devices. In particular, it defines the relationship between a device and a physical medium. This includes the layout of [[Lead (electronics)|pins]], [[voltage]]s, [[cable]] [[specification]]s, [[Network hub|Hub]]s, [[repeater]]s, [[network card|network adapter]]s, [[Host adapter|Host Bus Adapter]]s (HBAs used in [[Storage area network|Storage Area Network]]s) and more.

To understand the function of the Physical Layer in contrast to the functions of the Data Link Layer, think of the Physical Layer as concerned primarily with the interaction of a single device with a medium, where the Data Link Layer is concerned more with the interactions of multiple devices (i.e., at least two) with a shared medium. The Physical Layer will tell one device how to transmit to the medium, and another device how to receive from it (in most cases it does not tell the device how to connect to the medium). Obsolescent Physical Layer standards such as [[RS-232]] do use physical wires to control access to the medium.

The major functions and services performed by the Physical Layer are:

*Establishment and termination of a [[electrical connector|connection]] to a [[communication]]s [[Transmission medium|medium]].
*Participation in the process whereby the communication resources are effectively shared among multiple users. For example, [[Computer networking|contention]] resolution and [[flow control]].
*[[Modulation]], or conversion between the representation of [[digital data]] in user equipment and the corresponding signals transmitted over a communications [[channel (communications)|channel]]. These are signals operating over the physical cabling (such as copper and [[optical fiber]]) or over a [[electromagnetic wave#Radio waves|radio link]].

[[Parallel SCSI]] buses operate in this layer, although it must be remembered that the logical [[SCSI]] protocol is a Transport Layer protocol that runs over this bus. Various Physical Layer Ethernet standards are also in this layer; Ethernet incorporates both this layer and the Data Link Layer. The same applies to other local-area networks, such as [[IBM token ring|Token ring]], [[Fiber distributed data interface|FDDI]], and [[IEEE 802.11]], as well as personal area networks such as [[Bluetooth]] and [[IEEE 802.15#Task group 4 (Low Rate WPAN)|IEEE 802.15.4]].

== Interfaces ==
Neither the OSI Reference Model nor OSI protocols specify any programming interfaces, other than as deliberately abstract service specifications. Protocol specifications precisely define the interfaces between different computers, but the software interfaces inside computers are implementation-specific.

For example, [[Microsoft Windows]]' [[Winsock]], and [[Unix]]'s [[Berkeley sockets]] and [[UNIX System V|System V]] [[Transport Layer Interface]], are interfaces between applications (Layer 5 and above) and the transport (Layer 4). [[Network Driver Interface Specification|NDIS]] and [[Open Data-Link Interface|ODI]] are interfaces between the media (Layer 2) and the network protocol (Layer 3).

Interface standards, except for the Physical Layer to media, are approximate implementations of OSI Service Specifications.

== Examples ==
{| class="wikitable"
|-
!colspan="2"| Layer
!rowspan="2"| Misc. examples
!rowspan="2"| [[Internet protocol suite|TCP/IP]] suite
!rowspan="2"| [[Signaling System 7|SS7]]<ref>[http://www.itu.int/rec/T-REC-Q.1400/en/ ITU-T Recommendation Q.1400 (03/1993)], ''Architecture framework for the development of signalling and OA&M protocols using OSI concepts'', pp 4, 7.</ref>
!rowspan="2"| [[AppleTalk]] suite
!rowspan="2"| [[Open Systems Interconnection|OSI]] suite
!rowspan="2"| [[IPX]] suite
!rowspan="2"| [[Systems Network Architecture|SNA]]
!rowspan="2"| [[UMTS]]
|-
! #
! Name
|-
| 7
| Application
| [[HL7]], [[Modbus]]
| [[Network News Transfer Protocol|NNTP]], [[Session Initiation Protocol|SIP]], [[Simple Sensor Interface protocol|SSI]], [[Domain Name Service|DNS]], [[File transfer protocol|FTP]], [[Gopher (protocol)|Gopher]], [[HTTP]], [[Network File System (protocol)|NFS]], [[Network Time Protocol|NTP]], [[Dynamic Host Configuration Protocol|DHCP]], [[Short Message Peer-to-Peer Protocol|SMPP]], [[Simple Mail Transfer Protocol|SMTP]], [[Simple network management protocol|SNMP]], [[Telnet]]
| [[INAP]], [[Mobile Application Part|MAP]], [[Transaction Capabilities Application Part|TCAP]], [[ISDN User Part|ISUP]], [[Telephone User Part|TUP]]
| [[Apple Filing Protocol|AFP]], [[Zone Information Protocol|ZIP]], [[Routing Table Maintenance Protocol|RTMP]], [[AppleTalk|NBP]]
| [[FTAM]], [[X.400]], [[X.500]], [[Directory Access Protocol|DAP]], [[ROSE]], [[RTSE]], [[ACSE]]
| RIP, SAP
| [[APPC]]
|
|-
| 6
| Presentation
| [[Tabbed Document Interface|TDI]], [[ASCII]], [[EBCDIC]], [[Musical Instrument Digital Interface|MIDI]], [[MPEG]]
| [[MIME]], [[External Data Representation|XDR]], [[Secure Sockets Layer|SSL]], [[Transport Layer Security|TLS]] (Not a separate layer)
|
| [[Apple Filing Protocol|AFP]]
| ISO/IEC&nbsp;8823, X.226, ISO/IEC&nbsp;9576-1, X.236
|
|
|
|-
| 5
| Session
| [[Named Pipes]], [[NetBIOS]], [[Session Announcement Protocol|SAP]], [[Half Duplex]],[[Full Duplex]],[[Simplex]],[[Session Description Protocol|SDP]]
| Sockets. Session establishment in [[Transmission Control Protocol|TCP]]. [[Session Initiation Protocol|SIP]]. (Not a separate layer with standardized API.)
|
| [[AppleTalk|ASP]], [[AppleTalk|ADSP]], [[Printer Access Protocol|PAP]]
| ISO/IEC&nbsp;8327, X.225, ISO/IEC&nbsp;9548-1, X.235
| [[NWLink]]
| [[Data Link Control|DLC]]?
|
|-
| 4
| Transport
| [[NetBIOS Frames protocol|NBF]], [[nanoTCP]], [[nanoUDP]]
| [[Transmission Control Protocol|TCP]], [[User Datagram Protocol|UDP]],[[PPTP]], [[L2TP]], [[Stream Control Transmission Protocol|SCTP]], [[Real-time Transport Protocol|RTP]]
|
| [[Datagram Delivery Protocol|DDP]]
| ISO/IEC&nbsp;8073, TP0, TP1, TP2, TP3, TP4 (X.224), ISO/IEC&nbsp;8602, X.234
| [[Sequenced packet exchange|SPX]]
|
|
|-
| 3
| Network
| [[NetBIOS Frames protocol|NBF]], [[Q.931]]
| [[Internet Protocol|IP]], [[IPsec]], [[Address resolution protocol|ARP]], [[Internet Control Message Protocol|ICMP]], [[Routing Information Protocol|RIP]], [[Open Shortest Path First|OSPF]], [[Border Gateway Protocol | BGP]], [[Internet Group Management Protocol | IGMP]], [[IS-IS]]
| [[Signalling Connection Control Part|SCCP]], [[Message Transfer Part|MTP]]
| [[AppleTalk|ATP]] ([[TokenTalk]] or [[EtherTalk]])
| ISO/IEC&nbsp;8208, [[X.25]] ([[Packet-Layer Protocol|PLP]]), ISO/IEC&nbsp;8878, [[CONS|X.223]], ISO/IEC&nbsp;8473-1, [[CLNS|CLNP]] X.233.
| [[IPX]]
|
| [[Radio Resource Control|RRC]] ([[Radio Resource Control]]) [[PDCP|Packet Data Convergence Protocol]] ([[PDCP]]) and [[Broadcast/Multicast Control|BMC]] ([[Broadcast/Multicast Control]])
|-
| 2
| Data Link
| [[Ethernet|802.3 (Ethernet)]], [[IEEE 802.11|802.11a/b/g/n MAC/LLC]], [[IEEE 802.1Q|802.1Q (VLAN)]], [[Asynchronous Transfer Mode|ATM]], [[Hopling Discovery Protocol|HDP]], [[FDDI]], [[Fibre Channel]], [[Frame Relay]], [[HDLC]], [[Cisco Inter-Switch Link|ISL]], [[Point-to-Point Protocol|PPP]], [[Q.921]], [[Token Ring]], [[Cisco Discovery Protocol|CDP]]
| [[Point-to-Point Protocol|PPP]], [[SLIP]]
| [[Message Transfer Part|MTP]], [[Message Transfer Part|Q.710]]
| [[LocalTalk]],[[AppleTalk Remote Access]], [[Point-to-Point Protocol|PPP]]
| ISO/IEC&nbsp;7666, [[X.25]] ([[LAPB]]), [[Token Bus]], X.222, ISO/IEC&nbsp;8802-2 [[IEEE 802.2|LLC]] Type 1 and 2
| [[IEEE 802.3]] framing, [[Ethernet II framing]]
| [[Synchronous Data Link Control|SDLC]]
| [[Logical Link Control|LLC]] ([[Logical Link Control]]), [[Media Access Control|MAC]] ([[Media Access Control]])
|-
| 1
| Physical
| [[RS-232]], [[V.35]], [[V.34]], [[I.430]], [[I.431]], [[T-carrier|T1]], [[E-carrier|E1]], [[10BASE-T]], [[100BASE-TX]], [[Plain old telephone service|POTS]], [[Synchronous optical networking|SONET]], [[Synchronous optical networking|SDH]],[[Digital Subscriber Line|DSL]], [[IEEE 802.11|802.11a/b/g/n PHY]]
|
| [[Message Transfer Part|MTP]], [[Message Transfer Part|Q.710]]
| [[RS-232]], [[RS-422]], [[Twisted pair#Shielded Twisted Pair (STP)|STP]], [[PhoneNet]]
| [[X.25]] ([[X.21bis]], [[EIA/TIA-232]], [[EIA/TIA-449]], [[EIA-530]], [[G.703]])
|
| [[Twinaxial cabling|Twinax]]
| [[UMTS Physical Layer|UMTS L1]] ([[UMTS Physical Layer]])
|}

==Comparison with TCP/IP==
In the [[TCP/IP model]] of the Internet, protocols are deliberately not as rigidly designed into strict layers as the OSI model.<ref>RFC 3439</ref> RFC 3439 contains a section entitled "Layering [[considered harmful]]." However, TCP/IP does recognize four broad layers of functionality which are derived from the operating scope of their contained protocols, namely the scope of the software application, the end-to-end transport connection, the internetworking range, and lastly the scope of the direct links to other nodes on the local network.

Even though the concept is different than in OSI, these layers are nevertheless often compared with the OSI layering scheme in the following way: The Internet [[Application Layer]] includes the OSI Application Layer, Presentation Layer, and most of the Session Layer. Its end-to-end [[Transport Layer]] includes the graceful close function of the OSI Session Layer as well as the OSI Transport Layer. The internetworking layer ([[Internet Layer]]) is a subset of the OSI Network Layer, while the [[Link Layer]] includes the OSI Data Link and Physical Layers, as well as parts of OSI's Network Layer. These comparisons are based on the original seven-layer protocol model as defined in ISO 7498, rather than refinements in such things as the internal organization of the Network Layer document.

The presumably strict consumer/producer layering of OSI as it is usually described does not present contradictions in TCP/IP, as it is permissible that protocol usage does not follow the hierarchy implied in a layered model. Such examples exist in some routing protocols (e.g., OSPF), or in the description of [[tunneling protocol]]s, which provide a Link Layer for an application, although the tunnel host protocol may well be a Transport or even an Application Layer protocol in its own right.


==Births==
The TCP/IP design generally favors decisions based on simplicity, efficiency and ease of implementation.
*[[1034]] - [[Emperor Go-Sanjō]] of Japan (d. [[1073]])
*[[1499]] - [[Diane de Poitiers]], mistress of [[Henri II of France]] (d. [[1566]])
*[[1568]] - [[Adriano Banchieri]], Italian composer (d. [[1634]])
*[[1675]] - [[Paul Dudley]], Attorney-General of Massachusetts (d. [[1751]])
*[[1693]] - [[Charles Radclyffe]], British politician (d. [[1746]])
*[[1695]] - [[Pietro Locatelli]], Italian composer (d. [[1764]])
*[[1710]] - [[Abraham Trembley]], Swiss naturalist (d. [[1784]])
*[[1724]] - [[Guy Carleton, 1st Baron Dorchester]], British soldier and Governor of Quebec (d. [[1808]])
*[[1781]] - [[Eugène de Beauharnais]], son of [[Josephine de Beauharnais]] (d. [[1824]])
*[[1810]] - [[Paul Kane]], Canadian painter (d. [[1871]])
*[[1820]] - [[George Hearst]], American businessman and father of [[William Randolph Hearst]] (d. [[1891]])
*[[1841]] - [[Tom Emmett]], England cricketer (d. [[1904]])
*[[1849]] - [[Sarah Orne Jewett]], American writer (d. [[1909]])
*[[1851]] - [[Olga Konstantinovna of Russia]], Queen of Greece (d. [[1926]])
*[[1856]] - [[Louis Sullivan]], American architect (d. [[1924]])
* 1856 - [[Robert Stewart (cricketer)|Robert Stewart]], South African cricketer (d. [[1913]])
*[[1869]] - [[Fritz Pregl]], Slovenian chemist, [[Nobel Prize in Chemistry|Nobel Prize]] laureate (d. [[1930]])
*[[1875]] - [[Ferdinand Porsche]], Austrian automotive engineer (d. [[1951]])
*[[1882]] - [[Johnny Douglas]], England cricketer and boxer (d. [[1930]])
*[[1887]] - [[Frank Christian]], American musician (d. [[1973]])
*[[1897]] - [[Sally Benson]], American writer (d. [[1972]])
*[[1899]] - [[Frank Macfarlane Burnet]], Australian biologist, recipient of the [[Nobel Prize in Physiology or Medicine]] (d. [[1985]])
*[[1900]] - [[Maurice Dobb]], British economist (d. [[1976]])
* 1900 - [[Urho Kekkonen]], [[Finland|Finnish]] politician (d. [[1986]])
* 1900 - [[Percy Chapman]], England cricketer (d. [[1961]])
*[[1901]] - [[Eduard van Beinum]], Dutch conductor (d. [[1959]])
*[[1905]] - [[Carl David Anderson]], American physicist, [[Nobel Prize in Physics|Nobel Prize]] laureate (d. [[1991]])
* 1905 - [[John Mills (cricketer)|John Mills]], New Zealand cricketer (d. [[1972]])
*[[1907]] - [[Loren Eiseley]], American anthropologist (d. [[1977]])
*[[1908]] - [[Lev Semenovich Pontryagin]], Russian mathematician (d. [[1988]])
*[[1910]] - [[Kitty Carlisle]], American actress and television personality (d. [[2007]])
* 1910 - [[Maurice Papon]], French Nazi collaborator (d. [[2007]])
*[[1911]] - [[Bernard Mammes]], American cyclist (d. [[2000]])
*[[1913]] - [[Alan Ladd]], American actor (d. [[1964]])
*[[1914]] - [[Dixy Lee Ray]], American politician (d. [[1994]])
*[[1916]] - [[Eddie Stanky]], American baseball player (d. [[1999]])
*[[1918]] - [[Helen Wagner]], American actress
*[[1921]] - [[Marguerite Higgins]], American reporter and war correspondent, [[Pulitzer prize]] winner (d. [[1966]])
* 1921 - [[Thurston Dart]], English harpsichordist and conductor (d. [[1971]])
*[[1923]] - [[Mort Walker]], American cartoonist ([[Beetle Bailey]])
*[[1925]] - [[Bengt Lindström]], Swedish artist (d. [[2008]])
* 1925 - [[Shoista Mullodzhanova]], [[Shashmakom]] singer
* 1925 - [[Hank Thompson (music)|Hank Thompson]], American singer (d. [[2007]])
*[[1926]] - [[Alison Lurie]], American novelist
* 1926 - [[Irene Papas]], Greek actress
*[[1928]] - [[Gaston Thorn]], [[President of the European Commission]](d. [[2007]])
*[[1929]] - [[Carlo Clerici]], Swiss cyclist (d. [[2007]])
*[[1930]] - [[Cherry Wilder]], New Zealand author (d. [[2002]])
*[[1931]] - [[Albert DeSalvo]], [[The Boston Strangler]] (d. [[1973]])
* 1931 - [[Dick Motta]], American basketball coach
*[[1932]] - [[Eileen Brennan]], American actress
*[[1933]] - [[Tompall Glaser]], American singer
* 1933 - [[Basil Butcher]], West Indian cricketer
*[[1934]] - [[Freddie King]], American musician (d. [[1976]])
*[[1938]] - [[Eileen Brennan]], American actress
* 1938 - [[Caryl Churchill]], English playwright
* 1938 - [[Ryoji Noyori]], Japanese chemist, [[Nobel Prize in Chemistry|Nobel Prize]] laureate
*[[1940]] - [[Eduardo Galeano]], Uruguayan journalist
* 1940 - [[Pauline Collins]], English actress
*[[1941]] - [[Sergei Dovlatov]], Russian writer (d. [[1990]])
*[[1942]] - [[Al Jardine]], American musician ([[the Beach Boys]])
* 1942 - [[John Shrapnel]], English actor
*[[1943]] - [[Valerie Perrine]], American actress
*[[1943]] - [[Frank Lister]], English footballer
*[[1947]] - [[Eric Bell]], Irish guitarist ([[Thin Lizzy]])
* 1947 - [[Kjell Magne Bondevik]], Norwegian politician
*[[1948]] - [[Levy Mwanawasa]] - Zambian Politician (d. [[2008]])
*[[1949]] - [[Patriarch Peter VII of Alexandria]] (d. [[2004]])
* 1949 - [[José Pekerman]], Argentine football manager
*[[1950]] - [[Doug Pinnick]], American bassist and singer ([[King's X]])
*[[1953]] - [[Jean-Pierre Jeunet]], French film director
*[[1955]] - [[Steve Jones (musician)|Steve Jones]], English musician ([[Sex Pistols]])
*[[1956]] - [[Pat McGeown]], [[Provisional Irish Republican Army]] member
*[[1957]] - [[Garth Ancier]], American television executive
*[[1959]] - [[Merritt Butrick]], American actor (d. [[1989]])
*[[1962]] - [[Costas Mandylor]], Australian-born actor
*[[1963]] - [[Amber Lynn]], American porn star
* 1963 - [[Mubarak Ghanim]], UAE footballer
*[[1964]] - [[Adam Curry]], Internet entrepreneur
* 1964 - [[Spike Feresten]], American television writer
* 1964 - [[Junaid Jamshed]], Pakistani singer
* 1964 - [[Holt McCallany]], American actor
*[[1965]] - [[Charlie Sheen]], American actor
*[[1966]] - [[Vladimir Ryzhkov]], Russian politician
*[[1969]] - [[John Fugelsang]], American actor
* 1969 - [[Marianna Komlos]], Canadian bodybuilder, fitness model, professional wrestler, and valet (d. [[2004]])
*[[1970]] - [[Jeremy Glick (Flight 93)|Jeremy Glick]], American United Airlines Flight 93 passenger (d. [[2001]])
* 1970 - [[Gareth Southgate]], English footballer
*[[1971]] - [[Chabeli Iglesias]], Spanish journalist
* 1971 - [[Trevor St. John]], American actor
*[[1972]] - [[Natalia Estrada]], Spanish model and actress
* 1972 - [[Martin Straka]], Czech ice hockey player
* 1972 - [[Shim Eun-ha]], South Korean actress
*[[1973]] - [[Norihiko Hibino]], Japanese composer
* 1973 - [[Jennifer Paige]], American singer/songwriter
* 1973 - [[Damon Stoudamire]], American basketball player
*[[1974]] - [[Clare Kramer]], American actress
* 1974 - [[Rahul Sanghvi]], Indian cricketer
*[[1975]] - [[Cristobal Huet]], French hockey player
*[[1976]] - [[Ashley Jones]], American actress
* 1976 - [[Jevon Kearse]], American football player
* 1976 - [[Vivek Oberoi]], Indian actor
*[[1977]] - [[Rui Marques]], Angolan footballer
* 1977 - [[Olof Mellberg]], Swedish footballer
* 1977 - [[Nate Robertson]], American baseball player
*[[1978]] - [[John Curtis (footballer born 1978)|John Curtis]], English footballer
* 1978 - [[Paul Moor]], English ten-pin bowler
* 1978 - [[Michal Rozsival]], Czech ice hockey player
* 1978 - [[Nick Wechsler]], American actor
* 1978 - [[Terje Bakken|Valfar]], Norwegian [[Heavy metal music|heavy metal]] vocalist/musician ([[Windir]]) (d. [[2004]])
*[[1979]] - [[Tomo Miličević]], Croatian-born American musician ([[30 Seconds to Mars]])
*[[1980]] - [[The B.G.]], American rapper
* 1980 - [[Daniel Ruben Bilos]], Argentinian footballer
* 1980 - [[Jason McCaslin|Cone McCaslin]], Canadian bassist ([[Sum 41]])
* 1980 - [[Jennie Finch]], American softball player
*[[1981]] - [[Fearne Cotton]], British television presenter
*[[1982]] - [[Andrew McMahon]], American singer and songwriter
* 1982 - [[Kaori Natori]], Japanese singer and model
*[[1983]] - [[Augusto Farfus]], Brazilian racing driver
* 1983 - [[Nicky Hunt]], English footballer
* 1983 - [[Marcus McCauley]], American football player
* 1983 - [[Valdas Vasylius]], Lithuanian basketball player
*[[1984]] - [[Garrett Hedlund]], American actor
*[[1985]] - [[Scott Carson]], English footballer
* 1985 - [[Kelvin Wilson]], English footballer
*[[1986]] - [[Shaun White]], American snowboarder
*[[1987]] - [[Chris Fountain]], English actor
*[[1993]] - [[Rina Koike]], Japanese junior idol
<!--
Do not add yourself or people without Wikipedia articles to this list. No red links, please.
Do not trust "this year in history" websites for accurate date information.
Do not link multiple occurrences of the same year, just link the first occurrence.
-->


==Deaths==
==Remembering The OSI Layers==
*[[1402]] - [[Gian Galeazzo Visconti]], Duke of Milan (b. [[1351]])
Various [[mnemonic]]s have been created over the years to help remember the order of the OSI layers. Often cited are the following:
*[[1420]] - [[Robert Stewart, 1st Duke of Albany]], regent of Scotland
<!-- PLEASE DO NOT ADD MORE! They will be removed -->
*[[1592]] - [[Robert Greene (16th century)|Robert Greene]], English writer (b. [[1558]])
*'''P'''lease '''D'''o '''N'''ot '''T'''hrow '''S'''ausage '''P'''izza '''A'''way
*[[1634]] - [[Edward Coke]], English colonial entrepreneur and jurist (b. [[1552]])
*'''A'''ll '''P'''eople '''S'''eem '''T'''o '''N'''eed '''D'''ata '''P'''rocessing
*[[1653]] - [[Claudius Salmasius]], French classical scholar (b. [[1588]])
*'''P'''rogrammers '''D'''o '''N'''ot '''T'''hrow '''S'''alty '''P'''retzels '''A'''way
*[[1658]] - [[Oliver Cromwell]], Lord Protector of England (b. [[1599]])
<!-- PLEASE DO NOT ADD MORE! They will be removed -->
*[[1662]] - [[William Lenthall]], English politician (b. [[1591]])
*[[1720]] - [[Henri de Massue, Marquis de Ruvigny, 1st Viscount Galway|Henri de Massue]], French soldier and diplomat (b. [[1648]])
*[[1722]] - [[Ivan Skoropadsky]], Hetman of Ukraine (b. [[1646]])
*[[1729]] - [[Jean Hardouin]], French scholar (b. [[1646]])
*[[1766]] - [[Archibald Bower]], Scottish historian (b. [[1686]])
*[[1808]] - [[John Montgomery (delegate)|John Montgomery]], American Continental Congressman (b. [[1722]])
*[[1857]] - [[John McLoughlin]], Canadian trapper (b. [[1784]])
*[[1860]] - [[Aleksey Khomyakov]], Russian poet (b. [[1804]])
*[[1866]] - [[Konstantin Flavitsky]], Russian painter (b. [[1830]])
*[[1883]] - [[Ivan Turgenev]], Russian author (b. [[1818]])
*[[1886]] - [[William W. Snow]], American politician (b. [[1812]])
*[[1893]] - [[James Harrison (engineer)|James Harrison]], Scottish-born inventor (b. [[1816]])
*[[1903]] - [[Joseph Skipsey]], British poet (b. [[1832]])
*[[1914]] - [[Albéric Magnard]], French composer (b. [[1865]])
*[[1936]] - [[Nikita Balieff]], Armenian vaudevillian and impressario (b. [[1876]] or [[1877]])
*[[1948]] - [[Edvard Beneš]], [[President of Czechoslovakia]] (b. [[1884]])
*[[1961]] - [[Robert E. Gross]], American businessman (b. [[1897]])
*[[1962]] - [[E. E. Cummings]], American poet (b. [[1894]])
*[[1963]] - [[Louis MacNeice]], Irish poet (b. [[1907]])
*[[1964]] - [[Stewart Holbrook]], American author (b. [[1893]])
*[[1967]] - [[James Dunn (actor)|James Dunn]], American actor (b. [[1905]])
*[[1968]] - [[Isabel Withers]], American actress (b. [[1896]])
*[[1969]] - [[John Lester]], American [[cricket]]er (b. [[1871]])
*[[1970]] - [[Vince Lombardi]], American football coach (b. [[1913]])
* 1970 - [[Alan Wilson (musician)|"Blind Owl" Wilson]], American musician ([[Canned Heat]]) (b. [[1943]])
*[[1974]] - [[Harry Partch]], American composer (b. [[1901]])
*[[1980]] - [[Dirch Passer]], Danish actor (b. [[1926]]
*[[1980]] - [[Duncan Renaldo]], American actor (b. [[1904]])
*[[1981]] - [[Alec Waugh]], English writer (b. [[1898]])
*[[1983]] - [[Ellie Lambeti]], Greek actress (b. [[1926]])
*[[1987]] - [[Morton Feldman]], American composer (b. [[1926]])
*[[1991]] - [[Frank Capra]], American film director (b. [[1897]])
*[[1994]] - [[James T. Aubrey]], American television executive (b. [[1918]])
* 1994 - [[Billy Wright (footballer)|Billy Wright]], English former footballer (b. [[1924]])
* 1994 - [[Major Lance]], American singer (b. [[1939]])
*[[1996]] - [[Emily Kame Kngwarreye]], Australian artist (b. [[1910]])
*[[2000]] - [[Edward Anhalt]], American screenwriter (b. [[1914]])
*[[2001]] - [[Pauline Kael]], American film critic (b. [[1919]])
* 2001 - [[Thuy Trang]], American actress (b. [[1973]])
*[[2002]] - [[W. Clement Stone]], American entrepreneur (b. [[1902]])
*[[2003]] - [[Paul Jennings Hill]], American anti-abortion murderer (b. [[1954]])
*[[2005]] - [[R.S.R. Fitter|Richard S.R. Fitter]], British ornithologist and botanist (b. [[1913]])
* 2005 - [[William Rehnquist]], [[Chief Justice of the United States]] (b. [[1924]])
* 2006 - [[Tim Brown]], British musician ([[Not Your Hero]]) (b. [[1987]])
*[[2007]] - [[Jane Tomlinson]], British charity fund raiser (b. [[1964]])
* 2007 - [[Steve Ryan]], American actor (b. [[1947]])
* 2007 - [[Syd Jackson (New Zealand)|Syd Jackson]], Māori activist and trade unionist (b. [[1939]])
* 2007 - [[Carter Albrecht]], Musician (b. [[1973]])
*[[2008]] - [[Donald Blakeslee]], American aviator, led [[4th Fighter Group]] during [[World War II]]. (b.[[1918]])
<!--Steve Irwin died on September 4 (and is already listed there), not September 3, so please do not list his death here.-->
<!--
Do not add people without Wikipedia articles to this list
Do not trust "this year in history" websites for accurate date information
Do not link multiple occurrences of the same year, just link the first occurrence.
-->


==Holidays and observances==
==References==
*[[Calendar of Saints|RC Saints]] - [[Pope Gregory I]], [[Saint Marinus]], [[Remaclus]].
<references/>
*[[Qatar]] - [[Independence Day]] (from [[Great Britain]], [[1971]]).
*[[San Marino]] - Foundation ([[301]]) by [[Saint Marinus]].
*[[Taiwan]]/[[Republic of China]] - [[Armed Forces Day]].
*[[Australia]] - [[Flag of Australia|Flag Day]].
*[[Tunisia]] - [[Memorial Day]]


==External links==
==External links==
* [http://news.bbc.co.uk/onthisday/hi/dates/stories/september/3 BBC: On This Day]
* [http://standards.iso.org/ittf/licence.html (license agreement for downloading)] and [http://standards.iso.org/ittf/PubliclyAvailableStandards/s020269_ISO_IEC_7498-1_1994(E).zip ISO/IEC standard 7498-1:1994] ([[ZIP (file format)|ZIP format]])
* {{NYT On this day|month=09|day=03}}
* [http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-X.200-199407-I!!PDF-E&type=items ITU-T X.200 (the same contents as from ISO)]
* [http://www1.sympatico.ca/cgi-bin/on_this_day?mth=Sep&day=03 On This Day in Canada]
* {{PDFlink|1=[http://www.comsoc.org/livepubs/50_journals/pdf/RightsManagement_eid=136833.pdf OSI Reference Model — The ISO Model of Architecture for Open Systems Interconnection]|2=776&nbsp;KB}}, Hubert Zimmermann, IEEE Transactions on Communications, vol. 28, no. 4, April 1980, pp. 425 - 432.
----
* [http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Intro-to-Internet.html Internetworking Basics]
{{months}}


[[Category:CISSP]]
[[Category:September|S 03]]
[[Category:Network architecture]]
[[Category:ISO standards]]
[[Category:ITU-T recommendations]]
[[Category:OSI protocols]]
[[Category:Reference models]]


[[bs:OSI model]]
[[af:3 September]]
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[[ar:3 سبتمبر]]
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[[frp:3 septembro]]
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[[et:OSI raammudel]]
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[[el:μοντέλο αναφοράς OSI]]
[[es:Modelo OSI]]
[[be:3 верасня]]
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[[fa:مدل مرجع OSI]]
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[[bs:3. septembar]]
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[[ceb:Septiyembre 3]]
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[[he:מודל ה-OSI]]
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[[ka:OSI მოდელი]]
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[[fy:3 septimber]]
[[fur:3 di Setembar]]
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[[ga:3 Meán Fómhair]]
[[fi:OSI-malli]]
[[gan:9月3號]]
[[sv:OSI-modellen]]
[[gv:3 Mean Fouyir]]
[[gd:3 an t-Sultain]]
[[ta:திறந்த முறைமை வலைப்பின்னல் மாதிரி]]
[[th:OSI Model]]
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[[csb:3 séwnika]]
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[[sw:3 Septemba]]
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[[mk:3 септември]]
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[[pl:3 września]]
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[[tt:3. Sentäber]]
[[te:సెప్టెంబర్‌ 3]]
[[th:3 กันยายน]]
[[vi:3 tháng 9]]
[[tr:3 Eylül]]
[[uk:3 вересня]]
[[vec:3 de setenbre]]
[[vo:Setul 3]]
[[fiu-vro:3. süküskuu päiv]]
[[wa:3 d' setimbe]]
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[[bat-smg:Siejės 3]]
[[zh:9月3日]]

Revision as of 13:13, 2 October 2008

Template:SeptemberCalendar
September 3 in recent years
  2023 (Sunday)
  2022 (Saturday)
  2021 (Friday)
  2020 (Thursday)
  2019 (Tuesday)
  2018 (Monday)
  2017 (Sunday)
  2016 (Saturday)
  2015 (Thursday)
  2014 (Wednesday)

September 3 is the 246th day of the year (247th in leap years) in the Gregorian calendar; 119 days remain until the end of the year.

Events

Births

Deaths

Holidays and observances

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=OSI_model&oldid=242488226"