How to Implement BGP protocol in OMNeT++

To implement the BGP (Border Gateway Protocol) in OMNeT++, we need to simulation the characteristics of the BGP routers that should contain the exchange of routing information and the maintenance of the BGP routing table. Here, we offered step-by-step guide to implementing the BGP protocol in OMNeT++ using the INET framework:

Step-by-Step Implementation:

Install OMNeT++ and INET Framework

Make sure that you have to install the OMNeT++ and INET framework on the computer.

Create a New OMNeT++ Project

Open OMNeT++ IDE: Start the OMNeT++ IDE.
Create a New Project: Go to File -> New -> OMNeT++ Project. Name it (example., BGPSimulation).

Define the Network Topology

Create a new NED file to state the network topology that contain hosts and routers that will run the BGP protocol.

Example: BGP Network Topology (BGPNetwork.ned)

package bgpnetwork;

import inet.node.inet.StandardHost;

import inet.node.inet.Router;

network BGPNetwork

{

parameters:

@display(“bgb=800,400”);

submodules:

host1: StandardHost {

@display(“p=100,200”);

}

host2: StandardHost {

@display(“p=300,200”);

}

router1: Router {

@display(“p=200,100”);

}

router2: Router {

@display(“p=200,300”);

}

router3: Router {

@display(“p=400,200”);

}

connections allowunconnected:

host1.ethg++ <–> Eth10M <–> router1.ethg++;

host2.ethg++ <–> Eth10M <–> router2.ethg++;

router1.ethg++ <–> Eth10M <–> router3.ethg++;

router2.ethg++ <–> Eth10M <–> router3.ethg++;

}

Configure the Simulation

Create an initialization file of OMNeT++ to configure the parameters of the simulation.

Example: Configuration File (omnetpp.ini)

[General]

network = bgpnetwork.BGPNetwork

sim-time-limit = 200s

# Visualization

*.visualizer.canvasVisualizer.displayBackground = true

*.visualizer.canvasVisualizer.displayGrid = true

# Host Configuration

*.host*.numApps = 1

*.host*.app[0].typename = “UdpBasicApp”

*.host*.app[0].destAddresses = “host2”

*.host*.app[0].destPort = 5000

*.host*.app[0].messageLength = 1024B

*.host*.app[0].sendInterval = 1s

# Router Configuration

*.router*.numApps = 1

*.router*.app[0].typename = “BGPApp”

Create IP Address Configuration Files

Create XML files to term the IP address configuration for every node.

Example: IP Configuration File for host1 (host1.xml)

</interface>

</config>

Example: IP Configuration File for host2 (host2.xml)

</interface>

</config>

Example: IP Configuration File for router1 (router1.xml)

</interface>

</interface>

</config>

Example: IP Configuration File for router2 (router2.xml)

</interface>

</interface>

</config>

Example: IP Configuration File for router3 (router3.xml)

</interface>

</config>

Implement BGP Logic

Implement an application that handles the exchange of BGP messages and updates the routing table by simulating the BGP protocol.

Example: BGP Router Application (Pseudo-Code)

#include <omnetpp.h>

#include <inet/applications/base/ApplicationBase.h>

#include <inet/networklayer/ipv4/Ipv4Header.h>

#include <inet/networklayer/contract/ipv4/Ipv4Address.h>

#include <inet/networklayer/routing/Ipv4RoutingTable.h>

#include <map>

using namespace omnetpp;

using namespace inet;

class BGPApp : public ApplicationBase

{

protected:

std::map<Ipv4Address, Ipv4Address> bgpRoutingTable; // Destination, Next Hop

simtime_t updateInterval;

cMessage *updateTimer;

virtual void initialize(int stage) override;

virtual void handleMessageWhenUp(cMessage *msg) override;

void handlePacket(cMessage *msg);

void updateRoutingTable();

void sendBGPUpdates();

void processBGPUpdate(cMessage *msg);

void addOrUpdateRoute(const Ipv4Address &dest, const Ipv4Address &nextHop);

};

Define_Module(BGPApp);

void BGPApp::initialize(int stage) {

ApplicationBase::initialize(stage);

if (stage == INITSTAGE_APPLICATION_LAYER) {

updateInterval = par(“updateInterval”);

updateTimer = new cMessage(“updateTimer”);

scheduleAt(simTime() + updateInterval, updateTimer);

updateRoutingTable();

}

void BGPApp::handleMessageWhenUp(cMessage *msg) {

if (msg == updateTimer) {

sendBGPUpdates();

scheduleAt(simTime() + updateInterval, updateTimer);

} else if (msg->isPacket()) {

handlePacket(msg);

} else {

ApplicationBase::handleMessageWhenUp(msg);

}

void BGPApp::handlePacket(cMessage *msg) {

Ipv4Header *ipv4Header = check_and_cast<Ipv4Header *>(msg->removeControlInfo());

Ipv4Address destAddr = ipv4Header->getDestAddress();

auto it = bgpRoutingTable.find(destAddr);

if (it != bgpRoutingTable.end()) {

// Forward the packet to the next hop

Ipv4Address nextHop = it->second;

send(msg, “ifOut”, nextHop.getInterfaceId());

} else {

// Drop the packet if no route is found

delete msg;

}

void BGPApp::updateRoutingTable() {

// Example static routing table

bgpRoutingTable[Ipv4Address(“192.168.1.1”)] = Ipv4Address(“10.0.0.3”);

bgpRoutingTable[Ipv4Address(“192.168.1.2”)] = Ipv4Address(“10.0.0.3”);

}

void BGPApp::sendBGPUpdates() {

// Create and send BGP update packets to neighbors

for (auto &entry : bgpRoutingTable) {

cMessage *updateMsg = new cMessage(“BGPUpdate”);

updateMsg->addPar(“destAddr”) = entry.first.str().c_str();

updateMsg->addPar(“nextHop”) = entry.second.str().c_str();

send(updateMsg, “ifOut”);

}

void BGPApp::processBGPUpdate(cMessage *msg) {

// Process incoming BGP update messages

Ipv4Address destAddr = Ipv4Address(msg->par(“destAddr”).stringValue());

Ipv4Address nextHop = Ipv4Address(msg->par(“nextHop”).stringValue());

addOrUpdateRoute(destAddr, nextHop);

delete msg;

}

void BGPApp::addOrUpdateRoute(const Ipv4Address &dest, const Ipv4Address &nextHop) {

bgpRoutingTable[dest] = nextHop;

}

Configure and Initialize the Simulation

To use the custom BGP protocol, we have to make sure that the the routers are configured.

Example: Configuration File (omnetpp.ini)

[General]

network = bgpnetwork.BGPNetwork

sim-time-limit = 200s

# Visualization

*.visualizer.canvasVisualizer.displayBackground = true

*.visualizer.canvasVisualizer.displayGrid = true

# Host Configuration

*.host*.numApps = 1

*.host*.app[0].typename = “UdpBasicApp”

*.host*.app[0].destAddresses = “host2”

*.host*.app[0].destPort = 5000

*.host*.app[0].messageLength = 1024B

*.host*.app[0].sendInterval = 1s

# Router Configuration

*.router*.numApps = 1

*.router*.app[0].typename = “BGPApp”

*.router*.app[0].updateInterval = 30s

Run the Simulation

Build the Project: Right-click on project and select Build Project.
Run the Simulation: Click on the green play button in the OMNeT++ IDE to start the simulation.

In conclusion, we were offered you the essential details to implement the bgp protocols and their features using the INET frameworks in the OMNeT++. If needed, we can give you another script related to the topic.

We focus on managing routing information and maintaining BGP routing. Share your project details with us, and we will provide you with simulation results and guidance. Additionally, we offer implementation and project performance analysis of the BGP protocol using the OMNeT++ tool.