It defines seven layers or levels in a complete communication system. Each layer provides a service to the layer above it in the protocol specification. Isoosi model and its layers physical to application studytonight. The number of layers should be large enough that distinct functions should not be put in the same layer and small. Routing determines the best path to a particular destination. The network layer takes the segment, and appends the source and destination ip. A layered network model the osi reference model is composed of seven layers, each specifying particular network functions. It use to transfer data over a network which moves through different layer. Network architecture provides only a conceptual framework for communications between computers. Note that network layer addresses can also be referred to as logical addresses. Layer 3 the network layer layer 3, the network layer of the osi model, provides an endtoend logical addressing system so that a packet of data can be routed across several layer 2 networks ethernet,token ring, frame relay, etc.
Notice that the bottom layer is identified as the first layer. Describe the functionality of lan, man, and wan networks. Osi model 7 layers explained pdf layers functions what is osi model. An iso standard is the open systems interconnection osi model which was first introduced in the.
The process of breaking up the functions or tasks of networking into layers reduces complexity. Pdf the open systems interconnectionosi model isoiec 74981 is a. It can also perform basic routing functions between virtual lans. The model itself does not provide specific methods of communication. Pdf the osi model and network protocols emma greening. The network layer is also concerned with the following. This model defines seven layers that describe how applications run ning upon networkaware devices may communicate with each other. Application, presentation, session, transport, network, data link and physical in detail along with their. A protocol in the networking terms is a kind of negotiation and rule in between two networking entities. Logical addressing provides a unique address that identifies both the host, and the network that host exists on. Osi model layers in computer networks pdf by ramandeep singh page 1 osi osi stands for open system interconnection model osi model.
Actual communication is defined by various communication protocols. Osi model the network layer the network layer layer 3 controls internetwork communication, and has two key responsibilities. In other words, each layer has different features and network cases. This will provide you with an overview of the network process, which can then act as a framework for understanding the details of computer networking. A layer should be created where different level of abstraction is needed. Chapter 1 introduction to networking and the osi model. The layer 3 switch functions at the network layer and performs the multiport, virtual lan, data pipelining functions of a standard layer 2 switch. Presentation application session transport network data link physical layer 7 layer 6 layer 5 layer 4 layer 3 layer 2 layer. The function of each layer should be chosen according to the internationally standardized protocols. Pdf on oct 27, 2018, abbas miry and others published osi model find, read and cite all the research you need on researchgate. The osi model open system interconnection model defines a computer networking framework to implement protocols in seven layers. Osi layering layering is a structuring technique which permits the network of open systems to be viewed as logically composed of a succession of layers.