How to Implement Network Packets Transmission in OMNeT++
To implement the network packet transmission in OMNeT++, we have to setup a scenario that their nodes (like hosts, routers or switches) send and receive packets through the network. It is usually encompasses a configuration of network topology, setting up packet generators, and stating how packets are routed or switched amongst nodes. Follow the below process to achieve this:
Step-by-Step Implementation:
- Set Up OMNeT++ and INET Framework:
- Install OMNeT++: Make certain OMNeT++ is properly installed and configured.
- Install INET Framework: Download and install the INET framework that offers models for network protocols, nodes, and packet handling.
- Define the Network Topology:
Start by configuring a basic network topology where nodes (hosts, routers) can send and receive packets.
Example NED File (PacketTransmissionNetwork.ned):
package mynetwork;
import inet.node.inet.StandardHost;
import inet.node.inet.Router;
network PacketTransmissionNetwork
{
submodules:
hostA: StandardHost {
@display(“p=100,200”);
}
hostB: StandardHost {
@display(“p=300,200”);
}
router: Router {
@display(“p=200,200”);
}
connections allowunconnected:
hostA.pppg++ <–> ethernetLine <–> router.pppg++;
router.pppg++ <–> ethernetLine <–> hostB.pppg++;
}
This network has two hosts (hostA and hostB) linked through a router. This simple topology is suitable for representing packet transmission.
- Configure Packet Transmission:
Transmit packets amongst hostA and hostB by setting up the applications on these hosts that will generate and receive packets. We’ll use UDP applications for this purpose.
Example Configuration in omnetpp.ini:
network = PacketTransmissionNetwork
**.hostA.numApps = 1
**.hostA.app[0].typename = “UdpBasicApp”
**.hostA.app[0].destAddresses = “hostB”
**.hostA.app[0].destPort = 1234
**.hostA.app[0].messageLength = 1024B
**.hostA.app[0].sendInterval = 1s
**.hostB.numApps = 1
**.hostB.app[0].typename = “UdpSink”
**.hostB.app[0].localPort = 1234
In this configuration:
- hostA is set up with a UdpBasicApp to send UDP packets to hostB per second.
- hostB is configured with a UdpSink application to receive these packets on port 1234.
- Simulate Packet Transmission:
- Run the Simulation: Launch the simulation in OMNeT++ to monitor packet transmission from hostA to hostB via the router.
- Monitor the Process: During the simulation, you can visualize packet flows amongst nodes and assess how packets are directed.
- Analyze Transmission Results:
After running the simulation, monitor the different metrics include throughput, delay and packet loss to analyze the results.
Example Configuration for Recording Throughput:
network = PacketTransmissionNetwork
**.hostB.app[0].throughput.recordScalar = true
This configuration records the throughput at hostB permitting you to assess how much data was successfully received over the network.
- Implement Advanced Packet Transmission Scenarios:
You can extend the basic packet transmission setup to contain more difficult scenarios like:
- Multiple Traffic Flows: Deliver additional hosts and set up multiple traffic flows amongst them.
- QoS-Based Transmission: Execute Quality of Service (QoS) mechanisms to prioritize specific packets.
- Error Handling: Simulate packet loss and errors, and analyze how the network manages the problem.
Example: Multiple Traffic Flows
network MultiFlowNetwork
{
submodules:
hostA: StandardHost {
@display(“p=100,200”);
}
hostB: StandardHost {
@display(“p=300,200”);
}
hostC: StandardHost {
@display(“p=100,400”);
}
hostD: StandardHost {
@display(“p=300,400”);
}
router: Router {
@display(“p=200,300”);
}
connections allowunconnected:
hostA.pppg++ <–> ethernetLine <–> router.pppg++;
hostB.pppg++ <–> ethernetLine <–> router.pppg++;
hostC.pppg++ <–> ethernetLine <–> router.pppg++;
hostD.pppg++ <–> ethernetLine <–> router.pppg++;
}
Example Configuration for Multiple Traffic Flows:
network = MultiFlowNetwork
**.hostA.numApps = 1
**.hostA.app[0].typename = “UdpBasicApp”
**.hostA.app[0].destAddresses = “hostB”
**.hostA.app[0].destPort = 1234
**.hostA.app[0].messageLength = 1024B
**.hostA.app[0].sendInterval = 1s
**.hostC.numApps = 1
**.hostC.app[0].typename = “UdpBasicApp”
**.hostC.app[0].destAddresses = “hostD”
**.hostC.app[0].destPort = 5678
**.hostC.app[0].messageLength = 512B
**.hostC.app[0].sendInterval = 2s
**.hostB.numApps = 1
**.hostB.app[0].typename = “UdpSink”
**.hostB.app[0].localPort = 1234
**.hostD.numApps = 1
**.hostD.app[0].typename = “UdpSink”
**.hostD.app[0].localPort = 5678
In this scenario, both hostA and hostC send traffic to hostB and hostD, respectively, creating multiple simultaneous traffic flows.
- Implement Error Handling and Reliability Mechanisms:
Assess the network’s reliability by replicating packet loss, errors, and retransmissions.
Example: Introducing Packet Loss
network = PacketTransmissionNetwork
**.router.pppg[0].dropRate = 0.1 # Simulate 10% packet loss at the router
Example: Adding Retransmission Mechanism
void UdpBasicApp::handlePacketLoss(Packet *packet) {
if (isPacketLost()) {
retransmit(packet);
}
}
bool UdpBasicApp::isPacketLost() {
return uniform(0, 1) < 0.1; // 10% packet loss probability
}
void UdpBasicApp::retransmit(Packet *packet) {
EV << “Retransmitting packet: ” << packet->getName() << “\n”;
send(packet->dup(), “socketOut”); // Resend the packet
}
This code establishes a simple way to introduce packet loss and a retransmission mechanism to make sure consistency.
- Document and Report Findings:
After completing the simulations, document the results containing the packet transmission success rate, average delay, and any packet loss. This will help in understanding the network’s performance under different conditions.
This procedure will help you implement the Network Packets transmission in the OMNeT environment. It contains simulation process, configure the transmission of packets in the network and lastly, analysis the result to enhance it.
For effective implementation of network packet transmission in the OMNeT++ tool, you can refer to omnet-manual.com for excellent guidance.