On 7/14/06, sorin pasa <[EMAIL PROTECTED]> wrote:
> I'm trying to create "n" FTP connections from n computers to n
> computers (in pairs), connected through a node. I want to start a connection
> at second 0, and then close it after a second and in the same time open
> another. I don't know why, but the connections won't start.
> Please help. ....I'm attaching the code here:
>
> for {set i 1} {$i <= $clienti_num} {incr i} {
> set tcp [new Agent/TCP]
> set sink [new Agent/TCPSink]
> $ns attach-agent $sfile($i) $tcp
> $ns attach-agent $peer($i) $sink
> $ns connect $tcp $sink
> $tcp set fid_ $i
> $tcp set window_ 20
> $tcp set packetSize_ 100
>
> set ftp($i) [new Application/FTP]
> $ftp($i) attach-agent $tcp
> $ftp($i) set type_ FTP
> }
>
> for {set i 1} {$i <= $clienti_num} {incr i} {
> $ns at $i-1 "$ftp start"
> $ns at $i "$ftp($i) stop"
> }
Tcl doesn't do arithmetic evaluation by default. To get what you mean
(i.e. a transfer starting 1 second before $i), you need to write
"[expr {$i -1}]" in place of "$i-1". If you declare "global ftp" at
the top of your first for loop, that may help on the possible scoping
issue (I'm not sure how Tcl determines variable scope).
Phil Miller
