TCP variant reno

There are various number of variants in TCP protocol, there are a lot of pre validated popular variants in NS 2. First improvement over the traditional TCP (i.e, TCP taho) is Reno.
Here along with the program its also illustrated how to specify different shapes to the nodes and also how to change  their color !!!

set ns [new Simulator]
set nf [open reno.nam w]
$ns namtrace-all $nf

set tf [open reno.tr w]
$ns trace-all $tf

proc finish { } {
global ns nf tf
$ns flush-trace
close $nf
close $tf
exec nam reno.nam &
exit 0
}

set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]

$n3 label "destination"
$n0 color "red"
$n1 color "green"
$n2 color "yellow"
$n2 shape "square"
$n3 color "blue"

$ns duplex-link $n0 $n2 10Mb 1ms DropTail

$ns color $n0 "blue"

$ns duplex-link $n1 $n2 10Mb 1ms DropTail
$ns duplex-link $n2 $n3 10Mb 1ms DropTail

set tcp0 [new Agent/TCP/Reno]
$ns attach-agent $n0 $tcp0

set ftp0 [new Application/FTP]
$ftp0 set packet_Size_ 500
$ftp0 set interval_ 0.005
$ftp0 attach-agent $tcp0

set tcp1 [new Agent/TCP/Reno]
$ns attach-agent $n1 $tcp1

set ftp1 [new Application/FTP]
$ftp1 set packet_Size_ 500
$ftp1 set interval_ 0.005
$ftp1 attach-agent $tcp1

set sink0 [new Agent/TCPSink]
$ns attach-agent $n3 $sink0

set sink1 [new Agent/TCPSink]
$ns attach-agent $n3 $sink1

$ns connect $tcp0 $sink0
$ns connect $tcp1 $sink1

$ns at 0.1 "$ftp1 start"
$ns at 0.1 "$ftp0 start"
$ns at 10 "finish"

$ns run

Syntax for node color changing
" name_of_node" color "color_which_u_like" 
Syntax for node shaping
" name_of_node" shape  "standard_shape_u_like"
The network animator will something similar...