An Investigation into Transport Protocols and Data Transport ...

9.3. Internet Transfers 236
10 1
Stability
10 0
10 −1
Standard TCP HSTCP ScalableTCP HTCP FAST BicTCP
New−TCP
Figure 9.31: Stability from CERN to Dublin.
cwnd values. It also shows a similar range of values to that of FAST - but
with an even lower median value.
Unlike the test to Stanford, H-TCP has the worse goodput of all of the
New-TCP algorithms, with both a low median value and a large range of
goodput measurements. However, the measured quartiles of H-TCP’s results
suggest that it has better goodput performance than Standard TCP.
Stability
The stability of the New-TCP algorithms is shown in Figure 9.31. As demonstrated
with the goodput results, even with these relatively low latencies, the
cwnd values are sufficiently large enough to demonstrate the increased stabilities
of these New-TCP algorithms with their smaller decreases in cwnd
upon loss detection.
The results show that FAST has the lowest coefficient of variance per measurement,
followed by BicTCP. HSTCP, ScalableTCP and H-TCP perform
similarly, with H-TCP being the most variable with the largest inter-quartile
and normal range.
As FAST utilises the standard multiplicative decrease of 50% upon loss,