Ncsweek2 osi model
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Ncsweek2 osi model

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  • thanks for sharing this. here's some great site with more tutorials about tcp/ip and osi model: http://www.netguidea.com/
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  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction
  • CE51600-1 Software Development 22/09/11 Lecture 1 - Introduction

Ncsweek2 osi model Ncsweek2 osi model Presentation Transcript

  • CN3044 Network Programming
    • Lans, Wans, Model and Procotols
        • Network Structures
        • Lans
        • Wans
        • Standards Protocols
        • OSI Model
        • TCP/IP Model
    Slide
  • Network Types
    • Local Area Networks (LANs)
      • - A network serving a home, building or campus is considered a Local Area Network (LAN)
  • Network Types
    • Wide Area Networks (WANs)
      • LANs separated by geographic distance are connected by a network known as a Wide Area Network (WAN)
  • Network Types
    • The internet is defined as a
      • global mesh of interconnected networks
  • Network Components
  • Standards
    • Standards
        • processes or protocols that has been endorsed by the networking industry and ratified by a standards organization
        • are documented agreements containing technical specifications or other precise criteria that stipulate how a particular product or service should be designed or performed
    • Organisations responsible for standards
        • American National Standards Institute (ANSI)
        • Electronics Industry Alliance (EIA)
        • Institute of Electrical and Electronic Engineers (IEEE)
        • International Organization for Standardization (ISO)
        • International Telecommunication Union (ITU)
    Slide
  • IEEE Networking Specifications Slide
  • Protocols
    • A protocol:-
      • “ a mutually agreed treaty or diplomatic document ”
      • A set of predetermined rules
        • E. g. Traffic lights at a junction control the flow of vehicles on a road system
        • This is a simple, world-wide protocol
          • Although in France they do not use amber between red and green !
    Slide
  • The Seven Layer OSI Model
    • The OSI model breaks the process of communication down into several layers
    Application Presentation Session Transport Network Data link Physical Slide
    • Nmemonics –
      • P lease d o n ot t hrow s ausage p izza a way!
      • A ll P C’s s eem t o n etwork d ata p oorly
    At the top, the Application layer provides OS services for application software At the bottom, the Physical layer deals with wiring issues
  • OSI model – Why bother?
    • Real-world network protocols don’t implement the OSI seven layer protocol stack model
    • But nearly all network protocols are based on a simplified layered model
    • The layered model helps us think about the many processes involved in communicating over networks
    • A good model provides support for thinking
    Slide
    • Benefits include
      • assists in protocol design
      • fosters competition
      • changes in one layer do not affect other layers
      • provides a common language
  • A Fine-Grained Breakdown
    • This is a multilayer model
    • It shows two different “protocol stacks”
    • The courier service is analogous to network cabling (in a wired system)
    President/CEO Directors Quality Control Marketing Clerical Mail Room Mail Room Courier or Postal Service Clerical Design Manufacture Slide
  • Communication Between Two Systems Slide
  • ISO OSI Reference Model Version2 09/22/11 Slide Slide
  • Data Transformation Slide
  • The Application Layer
    • Provides interface to the software enabling programs to use network devices
    • Definition of the way that network services use the network
    • Defines how many services work, including
      • File sharing, Network Printing, Message Services etc
    • E.g Application Program Interface (API)
      • Routine that allows a program to interact with the operating system
      • Belongs to the Application layer of OSI Model
    • Microsoft Message Queuing (MSMQ)
      • Used in API network environment
      • Stores messages sent between nodes in queues
      • Forwards them to their destination
    Slide
  • The Presentation Layer
    • This layer “presents” data, which is to say it does some pre-processing, such as
      • data compression
      • encryption
      • character set conversion
    • Translates between the application and the network
    Slide
  • The Session Layer
    • A communications management layer
    • Defines how two computers synchronise, maintain and close a communication session
    • This includes such things as
      • security authentication
      • acknowledgement of data transfer
      • establishing and relinquishing a connection identity
    Slide
  • The Transport Layer
    • Data packet management
    • Ensures that chunks of data have been transferred without error – does lots of error and flow control
    • Takes data and packs it into chunks or chops it up into chunks suitable for transmission
    • Takes chunks and unpacks them or combines them into data streams
    Slide
  • The Network Layer
    • This is Internet Protocol address layer for path selection around the network
    • Routing of packets uses IP addresses
    • Network Layer Address
      • Resides at Network level of OSI Model
      • Follows hierarchical addressing scheme
      • Can be assigned through operating system software
    Slide
  • The Data Link Layer
    • Decodes packets into what are called frames which contain
      • Physical source and destination addressing
      • data validity / error checking
    • The network technology being used will influence how this layer works e.g. Ethernet, token ring …..
    • To accommodate shared access for multiple network nodes, the IEEE expanded the OSI Model by separating the Data Link layer into two sublayers
      • Logical Link Control (LLC) sublayer
      • Media Access Control (MAC) sublayer
    Slide
  • Subdivided Data Link Layer LLC and MAC sublayers Slide
  • Data Link Layer Sublayers
    • LLC
      • Upper sublayer
      • Provides common interface
      • Supplies reliability and flow control services
    • MAC – (Media Access Control)
      • Lower sublayer
      • Appends the physical address of the destination computer onto the frame
      • Number uniquely defining a network node
      • Manufacturer-hard codes the address
        • Block ID
        • Device ID
    Slide
  • The Physical Layer
    • This is the physical networking media layer which includes the cabling technology
    • Defines the transmission technique and the hardware definitions (connectors and so on)
    • Networking may take place over copper cables, optical fibres, infra-red radiation, radio waves… and this variation should be transparent to the user
    Slide
  • TCP/IP
    • The problem with the OSI model is a ‘concept’ not an actual implementation
    • TCP/IP is a set of protocols used .
  • Transmission Control Protocol/Internet Protocol (TCP/IP) OSI Model TCP/IP Slide
  • Layers with TCP/IP and OSI Model
  • OSI Model Summary Slide
  • Conclusion
    • We have discussed:-
    • Organizations that set standards for networking
    • Standard “root concepts” of networking
    • Layered models of processes and layers in our conceptual model of networking
    • Why protocols are required for interoperability
    • Details of the seven layers of the OSI model
    Slide