An Investigation into Transport Protocols and Data Transport ...

8.5. Summary 188
aggressive increase of FAST as it attempts to determine an optimal rate to
send data at.
BicTCP does very well in terms of reducing the number of losses due to
the use of its plateau as this helps maintain a high throughput and increases
the amount of time between congestion epochs (and hence loss events). The
subsequent additive increase after loss also facilitates the quick probing of
capacity and determination of a new plateau for cwnd, without substantially
increasing the overhead associated with the subsequent probing.
ScalableTCP, whilst very aggressive, does not have that much more of an
overhead than that the other algorithms under test (except FAST with low
BDP queue-size allocations).
8.5 Summary
The deployment of New-TCP is important in order for network applications
to be able to utilise future network resources effectively. However, due to the
requirement of large values of cwnd in order to maintain sufficient amounts
of data on the network to facilitate high throughput transport, the dynamic
of growing and maintain these large cwnd values plays a vital role in the
various performance traits of New-TCP algorithms.
All algorithms tested have very different characteristics in achieving large
cwnd values and the way they respond to loss events. However, a careful
choice of α and β is required to maintain a balance between flows such that
neither slow convergence nor lock-out occurs. There is a similar argument
for friendliness; the slow increase and large decrease of Standard TCP means
that it will nearly always result in low goodput performance when competing
with New-TCP flows which result in low fairness/friendliness.