RE: [ns] link handles

["Haobo Yu" <haoboy@isi.edu>]

It's just that you can't get a handle on duplex links. There's not a single
object that is a duplex link; each of them is just a function call that
creates 2 simplex linsk. So this does not prevent you from using them, but
when you want a handle, use something else.

> Thanks, but . . . all my other simulations (which work) have used duplex
> links.  How could they work?  --Pat.
>
> On Mon, 19 Jun 2000, Haobo Yu wrote:
>
> > There is no duplex link objects in ns. Use Simulator::link{} to get a
> > handle of a particular simplex link (n0, n1). See tcl/lib/ns-lib.tcl to
> > find this function.
> >
> > On Mon, 19 Jun 2000, Patrick Simen wrote:
> >
> > > Date: Mon, 19 Jun 2000 21:19:36 -0400 (EDT)
> > > From: Patrick Simen <psimen@eecs.umich.edu>
> > > To: ns-users@ISI.EDU
> > > Subject: [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
> > psimen@eecs.umich.edu
> > EECS Dept.
> > University of Michigan
> > ----------------------
> >
> >
> >
>
>

----------------------
Patrick Simen
psimen@eecs.umich.edu
EECS Dept.
University of Michigan
----------------------