"Buffer Requirements for TCP over ABR," ATM Forum/96-0517, April 1996

In our previous study [2], it was shown that cell loss due to limited buffering may degrade throughput considerably. The key question is how much buffering is required to avoid cell loss. This contribution attempts to answer that question.

We show that the maximum buffers required at the switch is proportional to the maximum round trip time of any VC through the link. The number of round-trips depends upon the the switch algorithm used. With our ERICA (modified) switch algorithm, we found that the buffering required is independent of the number of TCP sources. These observations are valid even when VBR or two- way traffic is used. We substantiate our arguments with simulation results.

Our simulations are carried out with a modified version of the ERICA algorithm. We also give a brief description of the modifications to ERICA which include avoidance of unnecessary spikes, correct counting of bursty sources and enhanced fairness.

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Presentation slides in Adobe Acrobat format (63,698 Bytes)


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