[ns] Network Simulator Questions

[Faisal Siddiqui]

Hi,

I have been investigating NS2 for research purposes for the last several
weeks. I have a very basic question and would really appreciate if you could
shed some valuable light on it.

I really stepped through each line of the code but can't really find when
and where the simulator assigns source and destination node addresses to the
packets. Could someone please explain in some detail how, when and where the
packets are assigned source and destination node addresses and from where
does the packets learn this information? Also, if there are more than 3
nodes (in case of ping agent), how does the packet establishes the source
and the destination nodes for traffic because in the Tcl script we only
connect the agents and do not specify the source and destination nodes.

Secondly, function "access (some argument) is spread all over the code. I
went through the manual as well but can't really understand why it is being
used in so many places. Could someone please explain what is the purpose of
using this function and how does this function when cast into different data
types provides information?

Thanks,
 - Faisal Siddiqui