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DRR Slide Show

DRR Slide Show. DRR Example:. Quantum = 50. deficit counters. queues. 40. 40. 10. 30. 0. 20. 30. 10. 45. 0. 40. 10. 20. 20. 0. 40. 40. 20. 35. 0. DRR Example:. Quantum = 50. deficit counters. queues. 40. 40. 10. 30. 50. 20. 30. 10. 45. 0. 40. 10. 20. 20.

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DRR Slide Show

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  1. DRR Slide Show

  2. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 0 20 30 10 45 0 40 10 20 20 0 40 40 20 35 0

  3. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 50 20 30 10 45 0 40 10 20 20 0 40 40 20 35 0

  4. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 20 20 30 10 45 0 40 10 20 20 0 40 40 20 35 0

  5. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 0 40 10 20 20 0 40 40 20 35 0

  6. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 50 40 10 20 20 0 40 40 20 35 0

  7. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 0 40 40 20 35 0

  8. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 50 40 40 20 35 0

  9. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 30 40 40 20 35 0

  10. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 10 40 40 20 35 0

  11. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 0 40 40 20 35 0

  12. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 10 40 40 20 35 50

  13. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 10 20 30 10 45 5 40 10 20 20 10 40 40 20 35 15 Note that we have completed one round. Observation: no flow has enough quota to send another message.

  14. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 60 20 30 10 45 5 40 10 20 20 10 40 40 20 35 15

  15. DRR Example: Quantum = 50 deficit counters queues 40 40 10 30 20 20 30 10 45 5 40 10 20 20 10 40 40 20 35 15

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  17. dDRR Slide Show

  18. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 50 0 20 30 10 45 50 0 40 10 20 20 50 0 40 40 20 35 50 0

  19. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 50 0 20 30 10 45 50 0 40 10 20 20 50 0 40 40 20 35 50 0 setup: request = 45 < deficit counter = 50 suspension flag not set decision: grant

  20. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 50 0 20 30 10 0 50 0 40 10 20 20 50 0 40 40 20 35 50 0 If previous setup was blocked: teardown ack 0, so do not subtract from deficit counter

  21. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 50 0 20 30 10 45 5 0 40 10 20 20 50 0 40 40 20 35 50 0 If previous setup was successful: teardown ack 45, so subtract 45 from deficit counter

  22. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 50 0 20 30 10 45 5 0 40 10 20 20 50 0 40 40 20 35 50 0 Next request wants 10, but 10 > deficit counter...

  23. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 50 0 20 30 10 45 55 1 40 10 20 20 50 0 40 40 20 35 50 0 Next request wants 10, but 10 > deficit counter… so block, set suspension flag and (pre)increase deficit coutner.

  24. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 60 1 20 30 10 45 55 1 40 10 20 20 50 1 40 40 20 35 65 1 Eventually, all flows would have exhausted the original 50 units assigned to their deficit counters… Observe that all suspension flags are set. Start a new round.

  25. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 60 0 20 30 10 45 55 0 40 10 20 20 50 0 40 40 20 35 65 0 Starting a new round: Clear all suspension flags.

  26. dDRR Example: Quantum = 50 deficit counters suspension flag queues 40 40 10 30 60 0 20 30 10 45 55 0 40 10 20 20 50 0 40 40 20 35 65 0 request = 10 < deficit counter = 55, suspension flag is unset, decision: grant

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