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[ns] link handles



I am trying to vary a link's bandwidth and delay dynamically.  I came
across Sally Floyd's email
(http://www-mash.CS.Berkeley.EDU/dist/archive/ns-users/0005/0409.html) about
her changes to ns which allow this, but only after trying lots of stuff
with links.

This brought up a question about whether the info in the ns manual,
chapter 6.4, is
correct.  It gives a list of commands that begin with "$ns_".  That seems
to work.  But it also lists commands like "$link up?".

I can't get those to work.  How do you get a handle to a link object? I
wrote:

set newlink [$ns duplex-link $n1 $n2 1Mb 10ms DropTail]

But then the command "$newlink up?" fails.  The failure message is:

invalid command name ""
    while executing
"$newlink up?"

And when I write: "puts stdout $newlink", I just get a blank line, as if
no handle to the link between $n1 and $n2 exists.  So how do you get a
handle for a link?  Or, what does "$link" refer to in chapter 6.4?

--Pat.

---------------------- 
Patrick Simen 
[email protected] 
EECS Dept.
University of Michigan 
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