Networking Standards And Protocols


Published on

Published in: Technology
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Networking Standards And Protocols

  1. 1. Networking<br />Standards and Protocols<br />
  2. 2. Standards and Protocols<br />The OSI Model<br />
  3. 3. What is the OSI Model?<br />
  4. 4. What is the OSI Model?<br />OSI Stands for Open Systems Interconnection.<br />The OSI model is a layered, abstract description for communications and computer network protocol design.<br />The Open Systems Interconnection model is a set of standard specifications that allows various computer platforms to communicate with each other openly.<br />It is concerned with the interconnection between systems – the way the systems exchange information – and not with the internal functions of the particular system<br />
  5. 5. What is the OSI Model?<br />It divides the network architecture into seven layers:<br />Physical<br />Data Link<br />Network<br />Transport<br />Session<br />Presentation<br />Application<br />
  6. 6. What is the OSI Model?<br />Each of these different layers has its own set of functions and only communicates with the layers directly above and below and with its opposite layer on other computers.<br />
  7. 7. Why a Layered Model?<br />
  8. 8. Why a Layered Model?<br />Change:<br />When changes are made to one layer, the impact on the other layers is minimized.<br />If the model consists of a single, all-encompassing layer, any change affects the entire model.<br />
  9. 9. Why a Layered Model?<br />Design:<br />A layered model defines each layer separately.<br />As long as the interconnections between layers remain constant, protocol designers can specialize in one area (layer) without worrying about how any new implementations affect other layers.<br />
  10. 10. Why a Layered Model?<br />Learning:<br />The layered approach reduces a very complex set of topics, activities, and actions into several smaller, interrelated groupings.<br />This makes learning and understanding the actions of each layer and the model generally much easier.<br />
  11. 11. Why a Layered Model?<br />Troubleshooting:<br />The protocols, actions, and data contained in each layer of the model relate only to the purpose of that layer.<br />This enables troubleshooting efforts to be pinpointed on the layer that carries out the suspected cause of the problem.<br />
  12. 12. Why a Layered Model?<br />Standards:<br />Probably the most important reason for using a layered model is that it establishes a prescribed guideline for interoperability between the various vendors developing products that perform different data communications tasks.<br />Remember, though, that layered models, including the OSI model, provide only a guideline and framework, not a rigid standard that manufacturers can use when creating their products.<br />
  13. 13. The Seven Layers of the OSI Model<br />
  14. 14. Physical Layer<br />
  15. 15. Physical Layer<br />The Physical layer is the lowest or first layer of the OSI Model. This layer contains the physical networking medium, such as cabling, connectors, and repeaters.<br />The Physical Layer defines:<br />Physical network structures<br />Mechanical and electrical specifications for using the transmission medium<br />Bit transmission encoding and timing rules <br />
  16. 16. Physical Layer<br />The physical layer does not include a description of the medium and does not provide any sort of error correction.<br />However, implementations of physical protocols are transmission-media-specific<br />
  17. 17. Physical Layer<br />The following network connectivity hardware are normally associated with the OSI physical layer:<br />Network interface boards (NIC, adaptors, and so on)<br />Hubs, and repeaters that regenerate electrical signals<br />Transmission media connectors, which provide the mechanical interface to interconnect devices to the transmission media (cables, BNC connectors, etc)<br />Modems and codec's, which perform digital analogue conversions. <br />
  18. 18. Data Link Layer<br />
  19. 19. Data Link Layer<br />The second layer of the OSI Model, the Data Link Layer, controls communications between the Network layer and the Physical layer.<br />Its primary function is to divide data it receives from the Network layer into distinct frames that can be transmitted by the Physical layer.<br />
  20. 20. Data Link Layer<br />The basic purposes of the data link layer protocol implementations are:<br />Organise the physical layer’s bits into logical groups of information called frames<br />Detect and correct errors<br />Control data flow<br />Identify computers on the network <br />
  21. 21. Network Layer<br />
  22. 22. Network Layer<br />The primary function of the Network Layer, the third layer in the OSI Model has the main objective of moving data to specific network locations.<br />
  23. 23. Network Layer<br />It does this by translating logical addresses into the appropriate physical address and then decides on the best route for the data to take from sender to receiver.<br />This appears similar to what the data link layer accomplishes through physical decide addressing.<br />However, data link layer addressing only operates on a single network<br />
  24. 24. Network Layer<br />The network layer describes methods for moving information between multiple independent networks, called internetworks. <br />
  25. 25. Transport Layer<br />
  26. 26. Transport Layer<br />The transport layer provides enhancements to the services of the network layer.<br />Its main tasks is to ensure that data sent form one computer arrives reliably, in the correct sequence and without errors at the receiving computer.<br />To ensure reliable delivery, the transport layer builds on the error control mechanism provided by the lower layer<br />
  27. 27. Transport Layer<br />This layer is the last chance for error recovery. The transport layer is also responsible for flow control.<br />It s here that there rate of transmission is determined, based on how fast the receiving computer can accept the data packets being sent to it.<br />Data on the sending computer is broken down into packets that are the maximum size that the type of network can handle. <br />
  28. 28. Session Layer<br />
  29. 29. Session Layer<br />The Session Layer is responsible for establishing and maintaining communication between two nodes on the network.<br />
  30. 30. Session Layer<br />The term session refers to a connection for data exchange between two parties; it is most often used in the context of terminal and mainframe communications, in which the terminal is a device with little (if any) of its own processing or disk capacity that depends on a host to supply it with applications and data processing services.<br />
  31. 31. Session Layer<br />Often, this layer also helps the upper layers identify and connect to the services that are available on the network.<br />If a communication session is broken, is the session layer that determines where to restart the transmission once the session has been reconnected<br />
  32. 32. Session Layer<br />This layer is also responsible for determining the terms of the communication session – it will determine which computer or node can communicate first and for how long<br />It is sometimes known as the ‘traffic cop’ of the network <br />
  33. 33. Presentation Layer<br />
  34. 34. Presentation Layer<br />The Presentation Layer serves as a translator between the application and the network.<br />At the Presentation layer, data become formatted in a schema that the network can understand; this format varies with the type of network used.<br />The Presentation Layer manages data encryption and decryption, such as the scrambling of system passwords.<br />
  35. 35. Application Layer<br />
  36. 36. Application Layer<br />The top or seventh layer of the OSI Model is the Application layer.<br />The Application provides interfaces to the software that enable programs to use network services.<br />
  37. 37. Application Layer<br />The term “Application Layer” does not refer to a particular software application, such as Microsoft Word, running on the network.<br />Instead, some of the services provided by the Application layer include file transfer, file management, and message handling for electronic mail.<br />
  38. 38. Application Layer<br />Examples of common functions include:<br />Protocols for providing remote file services, such as open, close, read, write, and shared access to files<br />File transfer services and remote database access<br />Message handling services for electronic mail applications<br />Global directory services to locate resources on a network<br />A uniform way of handling a variety of system monitors and devices<br />Remote job execution<br />