OMNET++: How do I send a message to a specific node based on probability? - omnet++

Question

I want to make a simulation such that node 1 has a chance to send its message to node 2 or node 3 based on a given probability, and node 2 should do the same. However, if node 3 receives the message at anytime, then the message is deleted. I tried to make it myself, but it is not working how as I planned. Out1 is an output that goes to either node 1 or 2, while Out2 is an output that goes to node 3. When the message starts at node 1 and it goes to node 3 first, then the message gets properly deleted, but other times it will immediately pop up that there are no more events and that the simulation is completed. I attached my node's cc files, and I am sure the other connections and stuff are correct. Any advice would be much appreciated, I'm still very new to omnet++. Thanks!
#include "nodes.h"
Define_Module(Nodes);
void Nodes::initialize()
{
prob1 = .9;
if(strcmp("node1", getName()) == 0){
if (uniform(0, 1) > prob1){
EV << "Sending initial message\n";
cMessage *msg = new cMessage("hw4Msg");
send(msg, "out1");
}
else {
EV << "Sending initial message\n";
cMessage *msg = new cMessage("hw4Msg");
send(msg, "out2");
}
}}
void Nodes::handleMessage(cMessage *msg) {
counter ++;
if((counter == 1)&&(strcmp("node3", getName()) == 0)) {
EV << getName() << "'s counter is " << counter << ", meaning ";
EV << getName() << " has captured the packet. The message will now be deleted.";
delete msg;
}
prob2 = .9;
if(strcmp("node1", getName()) == 0) {
if (uniform(0, 1) > prob2) {
EV << getName() << " Received message " << msg->getName() << " ,sending it out again\n";
EV << getName() << "'s counter is " << counter;
send(msg, "out1");
}
else {
EV << getName() << " Received message " << msg->getName();
send(msg, "out2");
}}
if(strcmp("node2", getName()) == 0) {
if (uniform(0, 1) < prob2) {
EV << getName() << " Received message " << msg->getName() << " ,sending it out again\n";
EV << getName() << "'s counter is " << counter;
send(msg, "out1");
}
else {
EV << getName() << " Received message " << msg->getName();
send(msg, "out2");
}
}}

Answer 1

What you are missing from your model: how you intend to generate packets. In your current code, you generate a single message (in the initialize() method in node1) and then send that towards other nodes. Once it finds its way to node3 the message is deleted and there is no more events for the simulation to simulate, so it stops.
Otherwise, it cannot immediately finish as the first message either goes first to node3 and gets deleted there in the next event, or it goes to node2 where it is forwarded to either node1 or node3 according to your code.
Unless you have mistyped the node2 name in your NED file. But either way, you should single step this in Qtenv and see each events one by one.
As a side note, this scenario can (almost) fully modeled using the modules from the samples/queueinglib, (a Source, Sink and a Classifier module). I highly recommend to take a look at that sample.