  We study the buffering requirements for zero cell loss for TCP over ABR. We
show that the maximum buffers required at the switch is proportional to the
maximum round trip time (RTT) of all VCs through the link. The number of
round-trips depends upon the the switch algorithm used. With our ERICA
[erica-final] switch algorithm, we find that the buffering required is
independent of the number of TCP sources. We substantiate our arguments with
simulation results.
