[ns] Dyanmic nature of link

["Kanwar Deep Singh" <singh_kdns@rediffmail.com>]

Hi ns-users,
 As per the ns manual to define a link we write script :
$ns duplex-link $Node0 $Node1 1Mb 10ms DropTali
after defining my topology & agents, i run ns.. which
simulates my topology...
 I want to know that is their any way to modify any link
in my simulation at the runtime...
i.e Assume that on above given link I'm forwarding
packets requiring 500Kb of bandwidth & at a particular
time instant the bandwidth requirements of pkts.
decreases to say 250Kb, how can I reflect this in my
simulation.I am interested in knowing the available
bandwidth on the link at the 2 different time intervals.
Thanks in advance,
Kanwar