Le model de reference osi pdf

It provided the first framework governing how information should be sent across a network. The international organization for standardization iso developed a sevenlayer model called open systems interconnection osireference model to help vendors and network experts to learn how data is transferred between networking devices. Le modele osi supinfo, ecole superieure dinformatique. In 1983, these two documents were merged to form a standard called the basic reference model for open systems interconnection. Layer 4 the transport layer provides a transition between the upper and lower layers of the osi model, making the upper and lower layers transparent from each other. The osi model consists of seven layers, each corresponding to a specific network function. Osi reference model the open systems interconnection osi model was developed by the international organization for standardization iso, and formalized in 1984. For information on the osi reference model and the role of each layer, please refer to the document internetworking basics. Osi model layers in computer networks pdf by ramandeep singh page 3 it splits the data or message into several fragments, delivering each fragment by a separate route and reassembling the fragments, report delivery errors, etc. Each layer has a different but specific processing. Encapsulation the data encapsulation process is defined as below. Open systems interconnection reference model osi model or osi seven layer model is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers.

The network software resolves an ambiguity among different types of network making it possible for all the machines in the network to. It explains the networking concepts and terms in a general manner. The most important concept behind the model is that each layer performs a specific function, provides services to the layer above it, and uses the services of the layer below it. In the sevenlayer osi model of computer networking, the physical layer or layer 1 is the first lowest layer.

Cours et exercices pdf sur reseaux et modele osi page 1. The computer in the above picture needs to send some data. Sep 09, 2015 secara teoritis, osi layer memiliki nama osi reference model for open networking, atau yang dalam bahasa indonesia dikenal dengan istilah model referensi jaringan terbuka. Open systems interconnection osi open systems interconnection in general. Osi sendiri merupakan kependekan dari open system interconnection. It use to transfer data over a network which moves through different layer.

The osi model not only provides a framework for creating and implementing networking standards, devices, and internetworking schemes but also explains the networking from a modular perspective, making it easier to understand and troubleshoot. Osi reference model the international standards organization iso proposal for the standardization of the various protocols used in computer networks specifically those networks used to connect open systems is called the open systems interconnection reference model1984, or simply the osi model. Once the osi model is understood, it will be easier to design, use, and, especially. The osi reference model the open systems interconnection osi reference model was developed by the international standards organisation iso as a model for computer communications architectures, and as a framework for developing protocol standards. It was intended as a first step towards international standardisation of communications protocols. It helps you to learn networking because it seperates a complex system into logical parts. Definition modele osi osi interconnexion des systemes. Network software is a set of primitives that define the protocol between two machines. Alongside this the iso developed a set of protocols that fit within this model.

International standard organization iso established a committee in 1977 to develop an architecture for systems communication. The osi model was first defined in raw form in washington, dc in february 1978 by hubert zimmermann of france and the refined but still draft standard was published by the iso in 1980. The most important concept is a discussion of the osi model and how data flows across a network. The picture below is an example of a simple data transfer between 2 computers and shows how the data is encapsulated and decapsulated. Saat ini, model osi sudah menjadi standar model arsitektural dalam sebuah jaringan komputer. Since then, other models such as the 5 layer tcpip model were developed, however the osi model is still used to map and categorise protocols. Modele osi, cours video gratuit sur les reseaux informatiques. Layer 5 the session layers primary function is managing the sessions in which data is transferred. It is seperated into 7 layers, which each function independently.

Figure 2 shows some of the important internet protocols and their relationship to the osi reference model. The osi open systems interconnect model is a concept used to describe the functions of a network. We have two reference models such as osi model and tcpip reference model, however, the osi model is a hypothetical one but the tcpip is absolutely practical model. Mcq questions and answers on data communication and computer networks or multiple choice questions with answers on data communication and networks from chapter communication network fundamentals. Jun, 2002 the osi open systems interconnect model is a concept used to describe the functions of a network. This model allows any two different systems to communicate regardless of their underlying architecture. Lahby universite hassan ii casablanca ens casablanca master mathematiques, cryptologie et securite informatique mmcsi 2. Cours sur le modele osi presentation et explications youtube. Protocoles et reseaux annee universitaire 20142015 m.

The open systems interconnection osi model is a reference tool for understanding data communications between any two networked systems. One important piece of information to keep in mind is that data flows 2 ways in the osi model, down data encapsulation and up data decapsulation. Dec 19, 20 salut tous le monde et bienvenue sur ce premier cours purement theorique sur le modele osi. Launched in 2015, it has all the normal details youd expect to find in a spatial database like buildings, field boundaries, roads, etc. It divides the communications processes into seven layers. Everything you wanted to know about the seven layers developed by international organization for standardization i. Open system interconnection osi reference model is the result of this effort.

Figure 1 shows the tcpip protocol suite in relation to the osi reference model. Definition des 7 couches du modele osi n des couches nom des couches definition couche 7 application. The open system interconnection reference model osi reference model or osi model is an abstract description for layered communications and computer network protocol design. The osi reference model is based on a proposal developed by the international standards organization iso. An osi model for cloud pete johnson in 1984, after years of having separate thoughts on networking standards, the international organization for standardization iso and the international telegraph and telephone consultative committee ccitt jointly published the open systems interconnection reference model, more commonly known as the osi model. Osi reference model helps networking device manufacturers to implement new network standards and policies. The osi reference model layers the model starts at the bottom with the physical layer layer 1, and ends at the top with the application layer layer 7. It contains multiple choice questions and answers about. The osi model has seven different layers, divided into two groups. Jan 31, 2020 prime2 is ordnance survey ireland s osi central database of spatial information. Cours sur le modele osi presentation et explications. Difference entre modele osi et tcp ip difference entre. Each layer both performs specific functions to support the layers above it and offers services to the layers below it. Tcp header encapsulation the application layers user data is converted for transmission on the network.

Osi model layers in computer networks pdf by ramandeep singh page 1 osi osi stands for open system interconnection model osi model. Modele osi et modele tcpip supinfo, ecole superieure d. This model is developed by the international organization of standardization iso and therefore also referred as iso osi model. Salut tous le monde et bienvenue sur ce premier cours purement theorique sur le modele osi. Ce modele a pour but daider les fournisseurs a creer des reseaux informatiques compatibles entre eux. Open system inter connection comprend sept couches.