Re: flow manager and lossy links.

[kfall@ee.lbl.gov]

>
> From:  "Frank J de Bruin" <fdebruin@wm.estec.esa.nl>
> To:    ns-users@mash.cs.berkeley.edu
> Subject: flow manager and lossy links.
> Date:  Mon, 11 Aug 1997 11:22:13 PDT
>
> 
> New to ns, I have started to look at ns-1.4.  While getting the basics right,
 
> I am trying to model a simple (satellite link). I would like to see how I can
 
> get bit error rates vs performance figures.
> 
> I know now how to use the flow manager to get statistics of the number bytes 
> traveling on the link, however, that doesn't seem to work with a link type 
> 'lossy-uniform'.
> 
> I realize that lossy-links have no queuing. Is that the reason why there is n
o 
> flow manager data? Is there a way around this?

Correct.  (This wasn't exactly a design goal, but just a result of not
putting it in).  I'd recommend changing the lossy link's enque function
to include the functionality in drop-tail.cc or red.cc... that is,
something like:
        if (flowmgr_) {
                if ((f = flowmgr_->findflow(p)) == NULL)
                        f = flowmgr_->newflow(p); 
                if (f) 
                        f->arrival(p);
        }
	...

	if (!packet_policy(p)) {
		if (f)
			f->drop(p);
	...

or something like that.

- K