[ns] How long it take to send 1000M data with FTP over a network?

[Xiaojun Cao <xjcao@263.net>]

hi,
    In my simulation, I want to know how long it takes to send 1000M 
data with FTP through the network.
    E.g. $ns at 0.2 "$ftp producemore 1000000"
        As I thought, just like real network,  some packets may get 
dropped, and the TCP agent may retransmit them. So how I get to know 
when the FTP sending is over. Will somebody give me some idea?
Thanks

X. Cao