Relevant Standards Bodies I

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Relevant Standards Bodies (I)

• ISO (www.iso.ch)
• Non-treaty agency of the United Nations.
• Collaborates standards development for
  information technology.
• ITU (www.itu.int)
• UN treaty agency that sets telecommunications
  standards.
• National standard bodies
• Canada CSA (www.csa.ca)
• USA ANSI (www.ansi.org)
• The US national standards body.
• Coordinates and accredits standards development
  across the US.

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Relevant Standards Bodies (II)

• IEEE (www.ieee.org)
• US based international professional organization.
• Develops standards and submits to ANSI for
  approval.
• IETF / IRTF
• Internet Engineering Task Force (www.ietf.org)
• Internet Research Task Force (www.irtf.org)
• EIA (www.eia.org)
• Electronic Industries Alliance

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OSI Layers
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Functions of the OSI Layers

• Physical
• The bits that are transmitted over the
  communication media.
• Deals with network hardware, bit encoding.
• Examples copper, fibre, radio, satellite.
• Data Link
• Activates, maintains, and deactivates the
  physical link between two adjacent nodes.
• Deals with framing, windowing, flow control,
  error detection and recovery.

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Functions of OSI Layers (2)

• Network
• Determines how best to route packets of data from
  source to destination via intermediate network
  nodes.
• Deals with addressing, routing, fragmentation,
  and congestion.
• Transport
• Ensures that data is transmitted reliably between
  source and destination.
• Deals with end to end integrity and quality of
  service.

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Functions of OSI Layers (3)

• Session
• Controls the dialogue between two host
  applications.
• Provides check points and error recovery.
• Reports exceptions to upper layers.
• Presentation
• Resolves data representation differences.
• Performs data compression and encryption.
• Application
• Perform functions to implement network
  applications.
• Examples e-mail, teleconferencing.

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Summary of Layer Functions
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TCP/IP Protocol Suite vs. OSI
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Connecting Devices and the OSI Model
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Function of a Repeater
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A Bridge in the OSI Model
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A Router in the OSI Model
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A Gateway in the OSI Model