A stream of packets is started at a slow rate to enable competing streams
to achieve transmission rate equilibrium. The transmission window is
initialized to a size smaller than an acceptable window advertised by the
receiving client. Upon receipt of an acknowledgement from the client that
a packet has been successfully transmitted, the size of the transmission
window is increased by the size of the acknowledged packet. This increase
continues until a threshold is reached, at which time further increases
are constrained by the maximum permitted segment size.