TCP (and SCTP) sucks on high speed networks

[Matt Wakeley <matt_wakeley@agilent.com>]

TCP's "congestion avoidance" algorithms are not compatible with high speed,
long distance networks.  The "cut transmit rate in half on packet loss and
increase the rate additively" algorithm will simply not work.

Consider a 10Gbs link to a destination half way around the world.  A packet
drop due to link errors (not congestion or infrastructure products) can be
expected about every 20 seconds.  However, with a RTT of 100ms (not even
across the continent), if a TCP connection is operating at 10Gbs, the packet
drop (due to link error) will drop the rate to 5Gbs.  It will take 4 *MINUTES*
for TCP to ramp back up to 10Gbps.

Therefore, there needs to be a change to TCP's congestion avoidance algorithm
for future high speed networks.  Since SCTP is based on the same algorithms,
it is doomed to the same fate.

-Matt