How to Implement border gateway protocol in OMNeT++
To implement the Border Gateway Protocol (BGP) in OMNeT++, we have to simulate a module that has to understand the BGP’s operation and its behavior. BGP is a standardized exterior gateway protocol designed to exchange routing information amongst autonomous systems (AS) on the internet. Contact omnet-manual.com for best guidance and implementation results.
Here, we provide the step-by-step process of BGP protocol:
Step-by-Step Implementation:
Step 1: Set Up OMNeT++ and INET Framework
- Install OMNeT++: Install the latest version of OMNeT++.
- Install INET Framework: Install the INET framework from the INET repository.
Step 2: Understand BGP Protocol
BGP is a path vector protocol that maintains the path information that gets updated dynamically based on the network topology changes. BGP uses few message types, including:
- Open: Establishes a peering session.
- Update: Advertises new routes or withdraws old ones.
- Keepalive: Keeps the connection alive.
- Notification: Reports errors.
Step 3: Create the BGP Protocol Module
Define the Module in .ned File
Generate a .ned file for the BGP protocol module.
simple BGP
{
parameters:
@display(“i=block/router”);
string asId; // Autonomous System ID
double keepaliveInterval @unit(s) = default(30s); // Interval for sending keepalive messages
gates:
input fromNetworkLayer;
output toNetworkLayer;
input fromPeer;
output toPeer;
}
Implement the Module in C++
Create the corresponding .cc and .h files.
BGP.h
#ifndef __BGP_H_
#define __BGP_H_
#include <omnetpp.h>
#include “inet/networklayer/contract/IRoutingTable.h”
#include “inet/common/INETDefs.h”
#include <map>
#include <set>
using namespace omnetpp;
using namespace inet;
class BGP : public cSimpleModule
{
private:
std::string asId;
double keepaliveInterval;
IRoutingTable *routingTable;
cMessage *keepaliveMsg;
std::map<L3Address, std::string> peerTable; // Maps peer addresses to their AS IDs
std::set<L3Address> advertisedRoutes; // Tracks advertised routes
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void sendKeepalive();
void processKeepalive(cMessage *msg);
void processUpdate(cMessage *msg);
void processOpen(cMessage *msg);
void processNotification(cMessage *msg);
void advertiseRoute(const L3Address &prefix);
void withdrawRoute(const L3Address &prefix);
public:
BGP();
virtual ~BGP();
};
#endif
BGP.cc
#include “BGP.h”
Define_Module(BGP);
BGP::BGP()
{
keepaliveMsg = nullptr;
}
BGP::~BGP()
{
cancelAndDelete(keepaliveMsg);
}
void BGP::initialize()
{
asId = par(“asId”).stringValue();
keepaliveInterval = par(“keepaliveInterval”);
routingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);
keepaliveMsg = new cMessage(“sendKeepalive”);
scheduleAt(simTime() + keepaliveInterval, keepaliveMsg);
}
void BGP::handleMessage(cMessage *msg)
{
if (msg == keepaliveMsg)
{
sendKeepalive();
scheduleAt(simTime() + keepaliveInterval, keepaliveMsg);
}
else if (strcmp(msg->getName(), “Keepalive”) == 0)
{
processKeepalive(msg);
}
else if (strcmp(msg->getName(), “Update”) == 0)
{
processUpdate(msg);
}
else if (strcmp(msg->getName(), “Open”) == 0)
{
processOpen(msg);
}
else if (strcmp(msg->getName(), “Notification”) == 0)
{
processNotification(msg);
}
else if (dynamic_cast<cPacket *>(msg))
{
// Handle incoming data packets if necessary
}
else
{
// Handle other messages
}
}
void BGP::sendKeepalive()
{
cMessage *keepalive = new cMessage(“Keepalive”);
send(keepalive, “toPeer”);
}
void BGP::processKeepalive(cMessage *msg)
{
// Process received keepalive message
delete msg;
}
void BGP::processUpdate(cMessage *msg)
{
// Process received update message
delete msg;
}
void BGP::processOpen(cMessage *msg)
{
// Process received open message
delete msg;
}
void BGP::processNotification(cMessage *msg)
{
// Process received notification message
delete msg;
}
void BGP::advertiseRoute(const L3Address &prefix)
{
cMessage *update = new cMessage(“Update”);
update->addPar(“prefix”) = prefix.str().c_str();
send(update, “toPeer”);
advertisedRoutes.insert(prefix);
}
void BGP::withdrawRoute(const L3Address &prefix)
{
cMessage *update = new cMessage(“Update”);
update->addPar(“withdrawnPrefix”) = prefix.str().c_str();
send(update, “toPeer”);
advertisedRoutes.erase(prefix);
}
Step 4: Integrate with Simulation Model
In the network simulation model, we have to integrate the BGP module.
Network Configuration .ned File
network BGPNetwork
{
submodules:
router1: StandardHost {
parameters:
@display(“p=100,100”);
asId = “AS1”;
}
router2: StandardHost {
parameters:
@display(“p=300,100”);
asId = “AS2”;
}
// Add more routers as needed
connections:
router1.pppg++ <–> { @display(“m=100,100”); } <–> router2.pppg++;
}
omnetpp.ini Configuration
network = BGPNetwork
*.router*.pppg[*].queue.typename = “DropTailQueue”
*.router*.ipv4.routingTable = “inet.networklayer.routing.manet.Router”
*.router*.networkLayer.networkProtocol.typename = “IPv4NetworkLayer”
*.router*.transportLayer.tcp.typename = “Tcp”
*.router*.transportLayer.udp.typename = “Udp”
*.router*.application[*].typename = “UdpBasicApp”
*.router*.application[*].destAddresses = “router1” // Set destination as needed
*.router*.application[*].destPort = 2000
*.router*.application[*].startTime = uniform(0s, 10s)
*.router*.application[*].sendInterval = uniform(1s, 2s)
*.router*.application[*].packetLength = 512B
*.router*.app[0].typename = “BGP”
Step 5: Test and Debug
- Run Simulations: Execute simulations to examine the actions of BGP module under various network conditions.
- Analyze Results: Evaluate the correctness and performance of implementation.
- Debugging: Use debugging tools of OMNeT++ to troubleshoot any issues.
At the end, this guide will walk you through the process of implementing a basic BGP module in OMNeT++ using the INET framework. For further queries or references, we can provide the required information.