An Investigation into Transport Protocols and Data Transport ...

9.3. Internet Transfers 238
1000
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Goodput (mbit/sec)
700
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0
Standard TCP HSTCP ScalableTCP HTCP FAST BicTCP
New−TCP
Figure 9.33: Goodput from CERN to LBL.
TCP. FAST also has the largest inter-quartile and normal range of all the
algorithms which gives it the least consistent goodput performance. However,
its inter-quartile range suggest that it consistently gains greater goodput than
the other New-TCP algorithms.
BicTCP and H-TCP have similar goodput performances. However, H-
TCP has the larger ranges of values - with a significantly larger goodput
range. Both algorithms also show that the minimum goodput is likely to be
higher than that of FAST’s, although BicTCP does have a significant number
of outlying points.
HSTCP and ScalableTCP both have relatively lower goodputs than that
of the other New-TCP algorithms with comparable performance. This was
found to be due to the slow growth of cwnd from the small cwnd values due
to the absence of slow start. Figure 9.34 shows that in the 5 minute tests,
HSTCP and ScalableTCP actually spends half of the time to grow cwnd to
sufficiently large enough values in order to fill the available bandwidth of the
path. Notable, however, is that the worst performing New-TCP algorithm
(HSTCP) under this network path still achieves approximately five times
higher goodput than that of Standard TCP.