Re: [ns] reg the generation of output trace file!!

[kunchanl <kunchanl@pollux.usc.edu>]

Oops...I thought he just wanted to print the trace file
contents to stdout...sorry for my oversight.

Kun-chan Lan

On Wed, 31 Jan 2001, Lloyd Wood wrote:

> On Tue, 30 Jan 2001, kunchanl wrote:
> 
> > I think you can modify either trace.cc or cmu-trace.cc(for
> > wireless)to get what you want.
> 
> Well, no. That won't do it by itself.
> 
> A while back I looked at interfacing ns to something else; I had the
> crazy idea of parsing a custom ns tracefile as it was written and
> feeding stuff back into ns as sets of here's-one-we-prepared-earlier
> Tcl routines that would be executed inside a scheduled trace
> procedure to schedule future events; basically sourcing the execution
> of the program (commands followed by the next scheduled time to
> read stdin) from stuff fed into stdin.
> 
> Nasty, but hey, it's all just pipes - or parsing your own
> fully-recorded transaction logs each way, as your control program
> reads the custom ns tracefile of events thus far and writes a command
> log to change or reschedule the future before scheduling the next read
> of said log, and ns writes its tracefile and reads the command log to
> get more future events to schedule.
> 
> So tracefiles can be useful for control. And all you have to do is
> schedule a procedure to start sourcing from stdin at time 0, and
> you've pretty much bootstrapped this monstrosity.
> 
> That's not what would be ideal here, since the control decisions are
> entirely internal to ns and nothing to do with e.g. some corba
> management thing. But it strikes me as possibly a hell of a lot easier
> than rewriting chunks of ns to do so; see the custom tracefile, don't
> like the output traffic you see from an agent, write out the Tcl
> instructions to schedule a command to kill that agent asap. (There are
> possibly some very neat ways of doing this - especially if you're
> using an otcl interpreter - depending on how you design your tracefile
> format, which can be separate and parallel to the usual trace-all
> via minor hackery of trace.cc.)
> 
> I'd rather try a hack like that than have to try and figure out how to
> get a queue or classifier to safely kill an agent on a different
> node... but since you could be waiting on further scheduled input,
> simulation time could be _slow_.
> 
> L.
> 
> has no idea if they ever actually got around to implementing this.
> 
> <L.Wood@surrey.ac.uk>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>
> 
> 
> > Kun-chan Lan
> > 
> > On Tue, 30 Jan 2001, Archana Krishna wrote:
> > >
> > > When a tcl code is written and simulation is performed, a trace
> > > file containing the output simulation is generated.
> > > 
> > > I need to perform some admission control decisions as flows are
> > > generated by the sources as to whether they should be admitted
> > > into the network. For this I would want the output to be viewed as
> > > they are generated and not wait until the whole trace file is
> > > generated....
> > > 
> > > Can anyone of you please let me know if its possible in ns and
> > > if so how to go about implementing it.
> > > 
> > > Thanks for your help
> > > Arch.
> 
>