Dynamics Of AIMD For Multiple Flows

  • We have seen in AIMD for a single flow that R = W(t) / RTT(t). In the case of multiple flows, RTT(t) tend to be constant. So the sending rate varies with the window size:

R = W(t) / RTT and it tends to equal W(t)

  • The queue occupancy B for multiple flows has a smooth geometric intuition and is almost constant in time, compared with the queue occupancy for a single flow.

aimd-multiple-flows
The sending rate tends to depend solely on the evolution of the window size over time – © Nick McKeown, Stanford University

  • AIMD is sensitive to packet loss, since R can be written as a function of p, p being the drop probability:

    R = √(3/2) * 1/(RTT*√p)

Regarding packet loss, remember that lost packets on one flow do not impact another flow.

References

CS144, Stanford University

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