TOPOLOGY

 

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

The following piece of Tcl code creates three duplex links between the nodes.

$ns duplex-link $n0 $n2 1Mb 10ms DropTail $ns duplex-link $n1 $n2 1Mb 10ms DropTail $ns duplex-link $n3 $n2 1Mb 10ms DropTail

You can save and start the script now. You might notice that the topology looks a bit awkward in nam. You can hit the 're-layout' button to make it look better, but it would be nice to have some more control over the layout. Add the next three lines to your Tcl script and start it again.

$ns duplex-link-op $n0 $n2 orient right-down $ns duplex-link-op $n1 $n2 orient right-up $ns duplex-link-op $n2 $n3 orient right

You will probably understand what this code does when you look at the topology in the nam window now. It should look like the picture below.