Re: [ns] Re: meaning of time in trace file

[George Riley <riley@cc.gatech.edu>]

> > Can anyone please tell me the exact meaning of 
> > the time field in the trace file? I mean:
> > 
> > For Send event, the time is: the FIRST bit of the packet 
> > is going to be sent out, or the LAST bit is just sent out?
> > 
> > For Receive event, the time is: the first bit of the packet
> > is going to be received, or the whole packet is just received?
> 
> last in both.
I disagree.  I believe tx event is FIRST bit out and rx event is LAST bit
in.  See code in delay.cc (simplified by me for discussion):

        double txt = txtime(p);
        s.schedule(target_, p, txt + delay);

The txtime is the time it takes to wiggle all the bits out the link,
starting fromthe first..delay is the link propagation delay.

Another clue is looking at trace files, and noting that the rx event is
(txtime  + delay) after the dequeue event for the same pkt.

George