[ns] Questions about Application Data

[Ken Sedgwick <ken@zodiacnetworks.com>]

Greetings,

I'm trying to construct a simulation of a system of interconnected
application-level programs.  I need to pass application data between
the simulated entities in this model.

So far I have created a subclass of Application, and have provided
a send method which attempts to create and send some application
data:
    PacketData * pdatap = new PacketData(nbytes);
    memcpy(pdatap->data(), datap, nbytes);
    agent_->send(nbytes, pdatap);

When I run the simulator, I get the following error:
    "Agent::sendmsg(int, AppData*, const char*) not implemented"

I discovered the following comment in agent.cc where the
indicated routine is defined:
/*
 * Place holders for sending application data
 */

What is my best plan of attack here?  Should I implement the needed
routines in agent.cc?  Is this hard for some reason?

I noticed other simulations with application level data seem to
avoid passing the data in the "payload" of the packets.  Is an
"out-of-band" mechanism for communicating the application data
a better way to go?

Many, many thanks in advance.

Ken

Ken Sedgwick
Zodiac Networks
ken@zodiacnetworks.com