Data Center Modeling and Simulation Using OMNeT++ paper - simulation

Question

my last codes are here:
import ned.IBidirectionalChannel;
import inet.nodes.inet.StandardHost;
import inet.nodes.inet.Router;
import inet.networklayer.autorouting.ipv4.FlatNetworkConfigurator;
import inet.nodes.ethernet.Eth10M;
import inet.nodes.ethernet.Eth100M;
package threetierdc;
module Rack
{
parameters:
int N #prompt(“ Nodes per rack ”);
#display("bgb=406,179");
gates:
inout iogate[];
submodules:
ComputingServer[N]: StandardHost {
}
AccessRouter: Router {
#display("p=278,50");
}
connections:
for i=0.. N-1 {
AccessRouter.ethg++ <--> Eth10M <-->
ComputingServer[i].ethg++;
}
AccessRouter.ethg++ <--> iogate++;
}
network ThreeTierDatacenter
{
parameters:
int N =default(1);
int AGR =default(2);
int CR =default(4);
submodules:
AGRouter[AGR]: Router;
CRouter[CR]: Router;
Racks[N]: Rack;
Configurator: FlatNetworkConfigurator;
connections allowunconnected:
for i=0..CR-1, for j= 0.. AGR-1{CRouter[i].ethg++ <--> Eth100M <--> AGRouter[j].ethg++; }
for i=0..0, for j=1 ..1 { AGRouter[i].ethg++ <--> Eth100M <--> AGRouter[j].ethg++; }
for i=0.. AGR-1 , for j=0..N-1 {AGRouter[i].ethg++ <--> Eth100M <--> Racks[j].iogate++ ;}
}
i got this error:
Error in module (cModule)ThreeTierDataCenter.Racks0during networksetup:Gate'ThreeTierDataCenter.Racks[0].iogate$i1'is not connected to a submodule(or internally to another gate of the same module).
I used this paper step by step :
Data Center Modeling and Simulation Using OMNeT++ AsadW. Malik and Samee U. Khan

Answer 1

The error message tells that you have already connected the output ethg port of AGRouters[0] to somewhere.
In this section of the .ned:
for i=0..1, for j=0..1
{
AGRouters[i].ethg++ <--> Eth100M <--> AGRouters[j].ethg++;
}
for i=0 and j=0 , you connect ethg++ of AGRouters[0] first to itself (AGRouters[0])
for i=0 and j=1 , you connect ethg++ of AGRouters[0] toAGRouters[1]
for i=1 and j=0 , you connect ethg++ of AGRouters[1] toAGRouters[0]
for i=1 and j=1 , you connect ethg++ of AGRouters[1] to itself (AGRouters[1])
I really doubt 1) and 4) are what you really want to achieve
network ThreeTierDatacenter
{
Parameter:
int N = default(4);
int AGR= default(4);
int CR= default(2);
Submodules:
AGRouters[AGR]: Router;
CRouter[CR]: Router;
Racks[N]: Rack;
Configurator: FlatNetworkConfigurator;
Connections allowunconnected: // <<<<<<<<<<<< you are missing this
for i=0..CR-1, for j= 0.. AGR-1{
CRouter[i].ethg++ <––> Eth100M <––> AGRouter[j].ethg++;}
for i=0..1, for j=0..1{
AGRouter[i].ethg++ <––> Eth100M <––> AGRouter[j].ethg++;}
for i=2..3, for j=2..3{
AGRouter[i].ethg++ <––> Eth100M <––> Racks[j].iogate++;}
}