An Investigation into Transport Protocols and Data Transport ...

10.2. New-TCP Suitability Study 249
data from the Tier-0 site to the Tier-1 sites very quickly, the raw throughput
is also an important issue.
For a small number of flows (or such that the sum of the number of flows’s
γ value does not exceed the bottleneck queue size), FAST is able to both
sustain high throughput, and maintain good friendliness with StandardTCP.
However, this requirement for ‘large’ queue sizes seriously affects FAST’s
performance profile. As the infrastructure of the Internet cannot be centrally
managed, tuning of such buffers is problematic.
Other New-TCP algorithms capable of high throughput, such as ScalableTCP,
maintains very bad RTT fairness between flows. This may also
become an issue as different destinations may share the same network bottleneck
- therefore TCP algorithms such as ScalableTCP is not advised for
deployment under this scenario. BicTCP and HSTCP maintains similar RTT
unfairness, however, it is much greater than that of StandardTCP. H-TCP,
however, is able to maintain relatively high throughput with very good RTT
fairness. Similarly, FAST - given sufficient buffering on the network path,
also maintains good RTT fairness.
As superfluous retransmissions may cause Internet collapse, maintaining
a low overhead is also important. H-TCP has a noticeable number of retransmissions
with longer latency paths when compared to the other algorithm;
whilst FAST is able to maintain significantly lower overhead by 2 orders of
magnitude.
10.2.2 Area 2
Area 2 has a requirement similar to Area 1, however, poses a greater risk of
the TCP transport needing to be shared with potentially high amounts of