How is Information Transferred? Developing an Intuition for Network Communication Protocols

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How is Information Transferred?Developing an
Intuition for Network Communication Protocols

• a 6.UAT concept talk by
• Olga Stroilova

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Information transfer networks are everywhere

• Internet connection Ethernet
• Laptop WiFi Wireless LAN
• Cell phones Mobile network
• How do these systems work?
• Read the lengthy (and complicated) 802 IEEE
  standard
• Build up an intuition by trying to design them
  yourself!

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What is Information and how do I Transfer It?

• Real life
• Sounds, letters, signs, pictures, movies
• Digital world
• 0s and 1s, voltage high and lows, radio
  waves
• Methods of Information Transfer
• Speech, Morse code, wire and radio
  communication
• Rules of transfer are called Communication
  Protocols

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Ethernet

• Idea Cut down costs by connecting all
  computers with a single wire
• Communication Protocol
• Listen to the wire and transmit if it is free
• Monitor wire during transmission
• If interference is detected, stop, wait and try
  again
• Play Nice Randomized Backoff Collision
  Detection

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Wireless Local Area Network

• Idea Use radio waves as transfer medium for
  increased portability
• Communication Protocol
• Divide 2.4 GHz radio wave band into channels
• Assign several transmissions to each channel
• Cannot detect collisions, so acknowledge each
  message
• Play First, Check Later Randomized Backoff
  Collision Avoidance

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Mobile Phone Network

• Idea Ensure quality of data stream by reducing
  probability of collision
• Communication Protocol
• Put up towers to divide area into cells
• Divide company frequency bandwidth into channels
• Allot one transmission per channel per cell
• Play By Yourself No Collisions, No Backoff

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In Conclusion

• Protocols are designed based on the
• product goals, limitations, and tradeoffs.
• To understand how they work, Think like an
  Engineer!
• Ethernet
• Cellular
  Wireless