CS138-lecture-20210408

SMTP socket programming assignment #

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TCP cont. #

Congestion control #

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https://media.pearsoncmg.com/aw/ecs_kurose_compnetwork_7/cw/content/interactiveanimations/tcp-congestion/index.html

Throughput #

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Fairness #

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Network layer #

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Quick review

  • The application layer is app to app.
  • Transport layer is process to process
  • Network layer is device to device (machine to machine), including routers

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ATM = asynchronous transfer model

For internet

  • Connection is at transport layer (TCP)
  • Datagrams (network connectionless)

ATM/X.25/Frame relay

  • Virtual connection is at network layer
  • Virtual circuits (network layer connection)
Note: The current internet does not use this

Network service model #

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Analogy: this is like the distance between cars on the road.

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CBR = constant bit rate, VBR = variable bit rate, AVB = available bit rate, UBR = undefined bit rate

In our internet service model, we do not guarantee anything. If we want to guarantee anything it must be done in the transport layer.

Virtual circuits and datagram networks #

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