[e2e] a few questions on TCP mechanism

[Craig Partridge]

In message <20040912105453.54129.qmail at web61204.mail.yahoo.com>, Zaphod Beebleb
rox writes:

>a. is it possible to have a steady state system where
>all flows get the amount of bandwidth they need, and
>yet all the sources are at a maximum value?
>In other words if there are 20 such flows and the
>network capacity is K, each should get K/20.
>Is this possible?

Sure.  There are lots of ways to do it if K is static and flows are long
lived.  The problem is that K is not static and a large fraction of
flows are short.

>b. If the only source of feedback is the destination
>point, how is it possible for me to:
>1. adjust my window size in T < RTT

In general, you shouldn't.  As I understand control theory, if you adjust
in times smaller than the RTT, your control loop is unstable.

Craig