set link0 [$ns duplex-link $sender1 $bridge0 100M 10ms DropTail]
set link1 [$ns duplex-link $sender2 $bridge0 100M 10ms DropTail]
set link2 [$ns duplex-link $bridge0 $bridge1 100M 10ms DropTail]
But it seems link-test is not stopping and there are some errors on the link test so I stopped the test..
Thank you
-Mo Dong