Course ILT The OSI model Unit objectives Explain the significance of the OSI model, label the seven layers of the OSI model, and describe services provided by each layer of the OSI model

Course ILT Topic A Topic A: Introduction to the OSI model

Course ILT Introducing the OSI model The OSI model is an international standard, originated to identify a common set of guidelines to facilitate communications between distinct information system components It provides a mechanism to establish a common set of protocols to support multiple-vendor solutions The real impact of OSI is the economic benefits derived from a common communications framework

Course ILT Introducing the OSI model With the OSI model you’ll be able to leverage the available tools and technologies from an end-to-end perspective The Open Systems Interconnect (OSI) model is an open, seven-layer model Each layer performs a different function in the exchange of data between different systems

Course ILT The OSI Model

Course ILT Activity A-1 Introducing the OSI model

Course ILT Layers of the OSI model The different layers of OSI model –OSI Physical layer –OSI Data link layer –OSI Network layer –OSI Transport layer –OSI Session layer –OSI Presentation layer –OSI Application layer

Course ILT OSI Physical layer The Physical layer governs how data is transmitted across the media It defines –The mechanical and electrical characteristics of the cables and connectors that link the network components –Data encoding –Bit synchronization

Course ILT OSI Data Link layer The Data Link layer specifies how devices attached to the network gain access to the various computing resources The two sub layers of this layer –Logical Link Control (LLC) –Media Access Control (MAC)

Course ILT The Data Link layer

Course ILT OSI Network layer The Network layer is responsible for establishing a unique network address and managing the transport of information packets between different networks It helps to coordinate the intercommunication activities between different networks

Course ILT OSI Network layer

Course ILT OSI Transport layer The Transport layer is responsible for the accuracy of the data transmission This fourth layer provides LAN network operating systems the intelligence to measure traffic performance

Course ILT OSI Transport layer

Course ILT OSI Session layer The Session layer is responsible for the integrity of the logical connection of the software session By using this layer two applications on different computers can establish, use, and end a connection called a session It provides synchronization between user tasks by placing checkpoints in the data stream

Course ILT OSI Session layer

Course ILT OSI Presentation layer The Presentation layer translates data into an appropriate transmission format The functions maintained –Terminal emulation –Encryption –Compression

Course ILT OSI Presentation layer

Course ILT OSI Application layer The Application layer provides a series of definitions that are used to provide network-wide system management functions such as software for file transfers, database access, and electronic mail

Course ILT Activity A-2 Discussing the layers of the OSI model

Course ILT Unit summary Learned about the significance of the OSI model, labeled the seven layers of the OSI model, and described services provided by each layer of the OSI model