ISO OSI Model

ISO OSI Model

• 1.
  The ISO -OSI Modela.k.a. OSI Modela.k.a. ISO OSI Reference Model1Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 2.
  Why ?To allowdifferent types of network hardware and software to communicate with each otherAvoidable duplication of equipment resourcesInability to communicate efficientlyTo breaks network communication into smaller, simpler parts that are easy to developTo facilitates standardization of network components to allow multiple – vendor development and support2Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 3.
  IntroductionEstablished in 1947ISO International Standard OrganizationMultinational body dedicated to worldwide agreementStandard of international levelCovers all aspects of network communicationsIt is Open System Interconnection MODELAllow two different Machines to connect without change in hardware and softwareIt is model for understanding and designing a network architecture 3Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 4.
  The ModelLayered frameworkDesignedfor communication across all types of computer system7 separate but related layerEach defines segment of process of moving information across networkDevelopers / Designers distilled the process of transmitting data to its most fundamental elementCreation of LayersRelated networking functions and its functionality are collected and discrete group ; became layer 4Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 5.
  Layered ArchitectureMessage fromDevice A to Device BTravels several intermediate NodesThese intermediate nodes involve only the first 3 layerPlease Do Not Touch Steve’s Pet Alligator5Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 6.
  Related required conceptsDataof L7 layer passed to layer 6Data of L6 layer passed to layer 6Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 7.
  Related required concepts…1 Peer to Peer ProcessLayer 2 provides services to Layer 3 (talking about Single Machine)Layer x provides services to Layer x (talking about In Between Machine)Communication between them governed by agreed upon series of rules - “Protocol”The process on each machine that communicates at given layer – “Peer to Peer Process”Only Physical layer (direct communication)1. Sending bit stream form Machine A to Machine B2. Data from Higher to move down3. Sending machine adds its own info part to message4. Added info are called ‘Header’(beginning of message)(Layers added Header 6,5,4,3,2) 7Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 8.
  Related required concepts…5. Added info are called ‘Trailer’(end of message)(Layers added Trailer 2) Every layer transform message for next layerAt receiving end the message is unwrapped (It is for every layer)Interfaces between layersAll receiving and sending of information and network information (between layers) only possible by interface ; between pairs of Layers.It defines what information, services a layer must provide to layer above it; process modulation.8Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 9.
  Related required concepts…Organization of layersThree subgroups 1 Layer (1,2,3) [Network Support Layer] Deals with physical aspect of data from 1 device to other devicea. Electric Specification b. Physical Connectionc. Physical Addressd. Transport timing2 Layer (5,6,7) [User Support Layer] Interoperability among unread software system3 Layer (4)End to End reliability of data transmission (Layer4)Reliable transmission of link (Layer 3)The process of putting Header and Trailer goes on Layer by Layer (except Layer 7 and Layer 1), Layer 2 both have Header and Trailer.9Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 10.
  Related required concepts…User support layerSoftwareLink between Software + HardwareN/W support layerHardwarePhysical Layer > Changed info Electromagnetic signal > Physical Link > L1 > (transformed info into bits > than Layer by Layer Corresponding Header and Trailer removed.10Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 11.
  Physical characteristics ofinterfaces and medium.
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  Representation of bits.
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  Physical topology.
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  Line configuration.
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  Data rate.
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  Synchronization of bits.
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  Transmission mode. Physicaland Data Link LayerCoordinates function required to transmit a bit stream over physical medium.2. Defines procedure and functions.Physical LayerFraming.
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  Physical addressing.
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  Flow control.
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  Error control.
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  Access control. 1Raw transmission from physical layer to reliably link(node to node delivery).2. Make physical layer error free. Data Link Layer11Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 22.
  Logical addressing.
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  Routing. Network andTransport Layer Source to destination delivery of packet across multiple network. Network LayerService-point addressing.
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  Segmentation and reassembly.
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  Connection control.
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  Flow control.
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  Error control. Source to destination delivery of entire message across multiple network. 2. Connection establish, Data transfer and Connection release.Transport Layer12Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 28.
  Dialog control.
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  Synchronization. Session andPresentation LayerIt is a network Dialog Controller.2. It establishes, maintains and synchronizes the interaction between communicating system .Session LayerTranslation.
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  Encryption.
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  Compression. 1. Concernedwith syntax and semantics of the information exchanged between two system.Presentation Layer13Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 32.
  Network virtual terminal.
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  File transfer, access,and management.
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  Mail services.
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  Directory services. ApplicationLayer and SummaryEnable user, (human or software) to access the network.2. Provides user interface and support for services (email, Remote file access, shared database management system).Application Layer14Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 36.
  Conclusion1. The International StandardsOrganization created a model called the Open Systems Interconnection, which allows diverse systems to communicate. 2. The seven-layer OSI model provides guidelines for the development of universally compatible networking protocols. 3. The physical layer coordinates the functions required to transmit a bit stream over a physical medium. 4. The data link layer is responsible for delivering data units from one station to the next without errors. 5. The network layer is responsible for the source-to-destination delivery of a packet across multiple network links. 6. The transport layer is responsible for the process-to-process delivery of the entire message. 7. The session layer establishes, maintains, and synchronizes the interactions between communicating devices. 8. The presentation layer ensures interoperability between communicating devices through transformation of data into a mutually agreed upon format. 15Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com
• 37.
  Reference1. Data Communications andNetworking - Behrouz A. Forouzan2. OSI model - Wikipedia, the free encyclopedia16Krishna Kumar Bohra (KKB), MCA LMCSTwww.selectall.wordpress.com