Question about two agents attach to one node?

[Wenjie Weng <weng@CS.UCLA.EDU>]

Hi,

I create two nodes.  Node 0 [n(0) in my script] has two agents attached 
to it. One uses FTP source object (the packet size for this traffic is
1000), the other uses TELNET source object (the packet size is 50). Node
1 also has two agents attached to it. When I run this simulation, the trace
file shows only the FTP source are transmitted. Can any one tell me why?

Thanks,
Wenjie


The following is the whole script:
=================================

set ns [new Simulator]
set f [open out.tr w]
$ns trace-all $f

proc finish {} {
        global ns f
        $ns flush-trace
        close $f
        exit 0
}

set n(0) [$ns node]
set n(1) [$ns node]
$ns duplex-link $n(0) $n(1) 100Mb 0.01ms DropTail

set telnet_src [new Agent/TCP/Reno]
$telnet_src set packetSize_ 50
set telnet_snk [new Agent/TCPSink/DelAck]
$ns attach-agent $n(0) $telnet_src
$ns attach-agent $n(1) $telnet_snk
$ns connect $telnet_src $telnet_snk

set ftp_src [new Agent/TCP/Reno]
$ftp_src set packetSize_ 1000
set ftp_snk [new Agent/TCPSink/DelAck]
$ns attach-agent $n(0) $ftp_src
$ns attach-agent $n(1) $ftp_snk
$ns connect $ftp_src $ftp_snk

set srs [$telnet_src attach-source Telnet]
$srs set interval_ 0
$ns at 0.0 "$srs start"

set src [$ftp_src attach-source FTP]
$ns at 0.0 "$src start"

$ns at 0.5 "finish"
$ns run


The following is the output in the trace file:
==============================================

+ 0 0 1 tcp 1000 ------- 0 0.1 1.1 0 0
- 0 0 1 tcp 1000 ------- 0 0.1 1.1 0 0
r 9e-05 0 1 tcp 1000 ------- 0 0.1 1.1 0 0
+ 0.10009 1 0 ack 40 ------- 0 1.1 0.1 0 1
- 0.10009 1 0 ack 40 ------- 0 1.1 0.1 0 1
r 0.100103 1 0 ack 40 ------- 0 1.1 0.1 0 1
+ 0.100103 0 1 tcp 1000 ------- 0 0.1 1.1 1 2
- 0.100103 0 1 tcp 1000 ------- 0 0.1 1.1 1 2
+ 0.100103 0 1 tcp 1000 ------- 0 0.1 1.1 2 3
- 0.100183 0 1 tcp 1000 ------- 0 0.1 1.1 2 3
r 0.100193 0 1 tcp 1000 ------- 0 0.1 1.1 1 2
r 0.100273 0 1 tcp 1000 ------- 0 0.1 1.1 2 3
+ 0.100273 1 0 ack 40 ------- 0 1.1 0.1 2 4
- 0.100273 1 0 ack 40 ------- 0 1.1 0.1 2 4
r 0.100286 1 0 ack 40 ------- 0 1.1 0.1 2 4
+ 0.100286 0 1 tcp 1000 ------- 0 0.1 1.1 3 5
- 0.100286 0 1 tcp 1000 ------- 0 0.1 1.1 3 5
+ 0.100286 0 1 tcp 1000 ------- 0 0.1 1.1 4 6
+ 0.100286 0 1 tcp 1000 ------- 0 0.1 1.1 5 7
- 0.100366 0 1 tcp 1000 ------- 0 0.1 1.1 4 6
r 0.100376 0 1 tcp 1000 ------- 0 0.1 1.1 3 5
- 0.100446 0 1 tcp 1000 ------- 0 0.1 1.1 5 7
r 0.100456 0 1 tcp 1000 ------- 0 0.1 1.1 4 6
+ 0.100456 1 0 ack 40 ------- 0 1.1 0.1 4 8
- 0.100456 1 0 ack 40 ------- 0 1.1 0.1 4 8
r 0.10047 1 0 ack 40 ------- 0 1.1 0.1 4 8
+ 0.10047 0 1 tcp 1000 ------- 0 0.1 1.1 6 9
+ 0.10047 0 1 tcp 1000 ------- 0 0.1 1.1 7 10
+ 0.10047 0 1 tcp 1000 ------- 0 0.1 1.1 8 11
- 0.100526 0 1 tcp 1000 ------- 0 0.1 1.1 6 9
r 0.100536 0 1 tcp 1000 ------- 0 0.1 1.1 5 7
- 0.100606 0 1 tcp 1000 ------- 0 0.1 1.1 7 10
r 0.100616 0 1 tcp 1000 ------- 0 0.1 1.1 6 9
+ 0.100616 1 0 ack 40 ------- 0 1.1 0.1 6 12
- 0.100616 1 0 ack 40 ------- 0 1.1 0.1 6 12
r 0.10063 1 0 ack 40 ------- 0 1.1 0.1 6 12
+ 0.10063 0 1 tcp 1000 ------- 0 0.1 1.1 9 13
+ 0.10063 0 1 tcp 1000 ------- 0 0.1 1.1 10 14
+ 0.10063 0 1 tcp 1000 ------- 0 0.1 1.1 11 15
- 0.100686 0 1 tcp 1000 ------- 0 0.1 1.1 8 11
r 0.100696 0 1 tcp 1000 ------- 0 0.1 1.1 7 10
- 0.100766 0 1 tcp 1000 ------- 0 0.1 1.1 9 13
r 0.100776 0 1 tcp 1000 ------- 0 0.1 1.1 8 11
+ 0.100776 1 0 ack 40 ------- 0 1.1 0.1 8 16
- 0.100776 1 0 ack 40 ------- 0 1.1 0.1 8 16
r 0.10079 1 0 ack 40 ------- 0 1.1 0.1 8 16
+ 0.10079 0 1 tcp 1000 ------- 0 0.1 1.1 12 17
+ 0.10079 0 1 tcp 1000 ------- 0 0.1 1.1 13 18
+ 0.10079 0 1 tcp 1000 ------- 0 0.1 1.1 14 19
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