fasp Fairness

Multiple FASP and TCP flows sharing a 2 Mbps bottleneck bandwidth (50 ms RTT). In this example a single FASP flow is started at the link capacity (1.97 Mbps). FASP 1 runs steadily at the target until the first TCP flow is started at two minutes. FASP 1 detects TCP 1 and immediately reduces rate to equally share the link at 1 Mbps. After two more minutes, a second TCP flow is started. Now FASP 1, TCP 1, and TCP 2 all equally share the link bandwidth at 660 kbps. Two minutes later, a second FASP flow starts up at a target of 1.97 Mbps. FASP 2 shoots up to the target but immediately detects the presence of the other flows and adjusts down as the other flows reapportion to equally share the link. Now all four flows are at 500 kbps. For the remainder of the test, one flow is terminated every two minutes. As each flow exits, the other flows reapportion the link bandwidth equally. The FASP flows zero in on the natural TCP rate at every interval, fairly sharing with TCP but with superior stability (less oscillation).

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