[e2e] Performance factors of TCP Equation Model

[Chua Hong Nung]

Factors of TCP Equation Model

Hi,
Firstly sorry my English is not good, but I have an unresolved problem which 
need
an answer.

TCP Equation Model of Padhye et al. is a function of RTT, RTO, loss rate and 
MSS.
Since most researcher substitute RTO with 4RTT, the only parameters 
determine
estimated throughputs are RTT and loss rate.

I have been thinking these two scenarios for quite a long time, but still 
unresolved.

Scenario 1:
Bottleneck 400Kbps
Share between 3 TCP flows and a TCP-Friendly Protocol flow.
Ideally, fair bandwidth share is 100Kbps for each flow.
Routers’ queue sizes are set to bandwidth delay product.
Minimum RTT for TCP-Friendly flow is 44ms.
Sources-------------Router----------------------Router----------------------Sinks
              1ms                          20ms                         1ms


Scenario 2:
Bottleneck 1Mbps
Share between 9 TCP flows and a TCP-Friendly Protocol flow.
Ideally, fair bandwidth share is 100Kbps for each flow.
Routers’ queue sizes are set to bandwidth delay product.
Minimum RTT for TCP-Friendly flow is 24ms.
Sources-------------Router----------------------Router----------------------Sinks
              1ms                          10ms                        1ms

If the TCP-Friendly Protocol flows in both scenarios employ the same model 
(Padhye et
al.), with different RTT how they will eventually achieve the ideal 
bandwidth share, i.e.
100Kbps. I can’t see loss rate can do that.

Thank you

Chua

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