Re: trace-driven simulations?

[Lee Breslau <breslau@parc.xerox.com>]

> greetings!
> 
> I am considering the possibility of using ns to do trace-driven
> simulations. However, I find little on trace-based traffic generation in
> ns document. It seems only 2 fields are supported: inter-packet time and
> packet size. Has anyone familiar with this? Or where can i find an
> example? Also, how to deal with the topology and src/dst address of the
> tracefile from real network?
> 
> Thanks!
> 
> Kai Tang
> UCSD/SDSC/Caida
> 

Kai,

There is an example in tcl/ex/tg.tcl that shows how to use the traffic
trace.  The model it assumes is that a given traffic trace is used
to send traffic from a single source to a destination (unicast
or multicast).   The script gives the commands for associating the
trace file with the source/destination agents.

If you have a trace file that contains traffic from multiple sources
and you want to use the current functionality in ns to drive a
simulation, you'd need to do some pre-processing to create multiple
files (each of course in the format expected by the simulator).

Lee