Understanding the host - To - host communications model

Building a Simple NetworkUnderstanding the Host-to-Host Communications ModelUnderstanding Host-to-Host CommunicationsOlder modelProprietaryApplication and combinations software controlled by one vendorStandards-based modelMultivendor softwareLayered approachWhy a Layered Network Model?Reduces complexityStandardizes interfacesFacilitates modular engineeringEnsures interoperable technologyAccelerates evolutionSimplifies teaching and learningThe Seven Layers of the OSI ModelThe Seven Layers of the OSI Model (Cont.)The Seven Layers of the OSI Model (Cont.)The Seven Layers of the OSI Model (Cont.)The Seven Layers of the OSI Model (Cont.)The Seven Layers of the OSI Model (Cont.)The Seven Layers of the OSI Model (Cont.)Data EncapsulationData De-EncapsulationPeer-to-Peer Communication Defines four layersUses different names for Layers 1 through 3Combines Layers 5 through 7 into single application layerTCP/IP StackTransport LayerSession multiplexingSegmentationFlow control (when required)Connection-oriented (when required)Reliability (when required)Reliable vs. Best-Effort ComparisonUDP CharacteristicsOperates at transport layer of OSI and TCP/IP modelsProvides applications with access to the network layer without the overhead of reliability mechanismsIs a connectionless protocolProvides limited error checkingProvides best-effort deliveryHas no data-recovery featuresUDP HeaderTCP CharacteristicsTransport layer of the TCP/IP stackAccess to the network layer for applicationsConnection-oriented protocolFull-duplex mode operationError checkingSequencing of data packetsAcknowledgement of receiptData-recovery featuresTCP HeaderTCP/IP Application Layer OverviewFile transferFTP TFTP Network File SystemE-mailSimple Mail Transfer ProtocolRemote loginTelnet rlogin Network managementSimple Network Management ProtocolName managementDomain Name SystemMapping Layer 3 to Layer 4Mapping Layer 4 to ApplicationsEstablishing a ConnectionThree-Way HandshakeFlow ControlTCP AcknowledgmentFixed WindowingTCP Sliding WindowingTCP Sequence and Acknowledgment Numbers