ipfw / dummynet using a timing mechanism?

[Thomas S. Crum]

Hello List,

I am running dummynet on freebsd to limit bandwidth.  I was wondering if
there is a way to set up dummynet, presumably with ipfw, that would
allow something of a rate fallback based on seconds.  For example, user
A begins a download and is piped at 10mb/s through dummynet.  After 5
seconds if that connection is still active it would be sent to a
different pipe, say at 5mb/s.  After another period of time it would be
sent to yet another slower pipe, and so on.  Any thoughts, configs,
answers are appreciated. Tom