RE: [ns] Error Model in Wireless Network

["jahn-isi" <jahn@ISI.EDU>]

However, we can not change the bandwidth of wireless networks in the middle of simulation.
For this we may need to do some hacking on ns.

Currently there is no place to set the bandwidth of wireless networks like one in command()
of delaymodel.cc.

-jahn

-----Original Message-----
From: owner-ns-users@ISI.EDU [mailto:owner-ns-users@ISI.EDU]On Behalf Of Nikolaos Katsarakis Austauschstud. (M. Schweigel)
Sent: Wednesday, May 30, 2001 4:24 AM
To: jahn-isi; ns-users
Subject: Re: [ns] Error Model in Wireless Network


It is possible to change the link bandwidth on the fly (haven't tested it yet, but it should work) using the command

$ns_ at 2.0 "$ns_ bandwidth $node_(r1) $node_(k1) 8Kb duplex"

for more information look at the /ns/tcl/test/test-suite-links.tcl

Nick

jahn-isi wrote:

> The following is what I think about your questions.
>
> >I think the variable error rate problem can be partly solved by using multi-state error model,
> >although it does not do all what we need, for example it's impossible if I would like to simulate the
> >error rate increasing gradually from 1% to 10% (packets) during a period from  0 to 10 seconds.
>
> Somehow, by the multi-state model, we can model the gradual error increase even though the
> transitions would be periodical ultimately. Like, we can create 10-state error model with time transition unit and
> we can specify each transition time from a state to another.  I am not sure why you think that the gradual
> error increase is impossible.
>
> >The second problem, (the changes of physical bandwidth) does not seem to have an answer yet. I mean,
> >can we set a link to have "multi-state" bandwidth or can we change the channel bandwidth "on the
> >flight".
>
> I am not sure about this. I guess that the dyanmic change of the physical bandwidth is impossible
> in ns now since most configuration parameters are statically set at the start time.
>
> Thanks
>
> -jahn