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How to Implement bgp routing in OMNeT++

To implement the Border Gateway Protocol (BGP) routing in OMNeT++ is a multifaceted task because the BGP acts as a primary exterior gateway protocol which is used to transfer information among the autonomous systems (ASes) on the Internet. BGP is a path vector protocol, and its execution wants handling aspects like route advertisement, policy enforcement, and path selection as per the attributes like AS path, next-hop, and other policy considerations.

We offered step-by-step guide to implementing a basic BGP routing protocol in OMNeT++ in the following below:

Step-by-Step Implementation:

Step 1: Set Up OMNeT++ and INET Framework

  1. Install OMNeT++:
    • Make certain that you have OMNeT++ installed on your system.
  2. Install the INET Framework:
    • Download and install the INET Framework, which offers numerous networking protocols and models. INET can be downloaded from the INET GitHub repository.

Step 2: Create a New OMNeT++ Project

  1. Create the Project:
    • Open OMNeT++ and create a new OMNeT++ project via File > New > OMNeT++ Project.
    • Name the project (e.g., BGPRoutingSimulation) and create the project directory.
  2. Set Up Project Dependencies:
    • Guarantee the project references the INET Framework by right-clicking on your project in the Project Explorer, navigating to Properties > Project References, and checking the INET project.

Step 3: Define the Network Topology

  1. Create a NED File:
    • With the help of NED language, we have to describe the network topology which contains routers (acting as BGP peers) and possibly some hosts.

Example:

network BGPRoutingNetwork

{

submodules:

as1_router1: Router;

as2_router1: Router;

as3_router1: Router;

host1: StandardHost;

host2: StandardHost;

connections allowunconnected:

as1_router1.ethg++ <–> Eth10Gbps <–> as2_router1.ethg++;

as2_router1.ethg++ <–> Eth10Gbps <–> as3_router1.ethg++;

as1_router1.ethg++ <–> Eth1Gbps <–> host1.ethg++;

as3_router1.ethg++ <–> Eth1Gbps <–> host2.ethg++;

}

  1. Configure Network Parameters:
    • To simulate the realistic network environment, we have to generate essential link parameters like bandwidth, delay, and packet loss to simulate a realistic network environment.

Step 4: Implement the BGP Routing Protocol

  1. Define the BGP Routing Module:
    • Create a new module in NED for the BGP routing protocol. This module will maintain the BGP peer sessions, route advertisements, and path selection.

Example (in NED):

simple BGPRouting

{

parameters:

@display(“i=block/router”);

gates:

inout lowerLayerIn[];

inout lowerLayerOut[];

}

  1. Implement BGP Routing Logic in C++:
    • Implement the routing logic in C++ that manages BGP sessions, exchanges routing information, and selects routes based on BGP policies.

Example (C++ implementation):

#include <vector>

#include <map>

#include “inet/common/INETDefs.h”

#include “inet/networklayer/contract/IRoutingTable.h”

#include “inet/networklayer/ipv4/IPv4RoutingTable.h”

#include “inet/networklayer/ipv4/IPv4Route.h”

#include “inet/routing/bgpv4/BGPv4.h”  // Assuming you have a BGPv4 model

class BGPRouting : public cSimpleModule

{

private:

struct BGPRoute {

std::string prefix;

std::string nextHop;

int asPathLength;

std::vector<int> asPath;  // AS Path

};

std::map<std::string, BGPRoute> bgpTable;  // Prefix -> BGPRoute

IRoutingTable *inetRoutingTable;

cMessage *updateMsg;

simtime_t updateInterval;

protected:

virtual void initialize() override;

virtual void handleMessage(cMessage *msg) override;

void sendUpdateMessages();

void processUpdateMessage(cMessage *msg);

void selectBestPath();

};

Define_Module(BGPRouting);

void BGPRouting::initialize() {

inetRoutingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);

updateInterval = par(“updateInterval”);

updateMsg = new cMessage(“BGPUpdate”);

scheduleAt(simTime() + updateInterval, updateMsg);

 

// Initialize the BGP routing table (e.g., with directly connected networks)

// BGPTable might need more initialization based on the network topology and BGP peers

}

void BGPRouting::handleMessage(cMessage *msg) {

if (msg == updateMsg) {

sendUpdateMessages();

scheduleAt(simTime() + updateInterval, updateMsg);

} else {

processUpdateMessage(msg);

}

}

void BGPRouting::sendUpdateMessages() {

// Create and send BGP update messages to peers

// Include route advertisements in the update messages

for (int i = 0; i < gateSize(“lowerLayerOut”); i++) {

cPacket *updatePacket = new cPacket(“BGPUpdate”);

// Add BGP update message data

send(updatePacket, “lowerLayerOut”, i);

}

}

void BGPRouting::processUpdateMessage(cMessage *msg) {

// Process incoming BGP update messages from peers

// Extract routing information and update the BGP routing table

delete msg;  // Don’t forget to delete the message

}

void BGPRouting::selectBestPath() {

// Implement BGP best path selection based on the BGP table

// Apply BGP policies like AS path length, next-hop reachability, etc.

// Update the local routing table (inetRoutingTable) with the best routes

}

    • BGP Routing Table: The BGP routing table stocks route information received from peers containing prefixes, next hops, and AS paths.
    • Session Management: Handle BGP sessions with peers, interchanging routing information over BGP update messages.
    • Best Path Selection: Execute BGP best path selection, considering AS path length, next-hop reachability, and other BGP policies.

Step 5: Set Up the Simulation

  1. Configure the Simulation in omnetpp.ini:
    • Generate the simulation parameters like simulation time, network settings, and traffic patterns.

Example:

network = BGPRoutingNetwork

sim-time-limit = 200s

**.scalar-recording = true

**.vector-recording = true

# Application traffic configuration

*.host1.numApps = 1

*.host1.app[0].typename = “UdpBasicApp”

*.host1.app[0].destAddress = “host2”

*.host1.app[0].destPort = 5000

*.host1.app[0].messageLength = 1024B

*.host1.app[0].sendInterval = uniform(1s, 2s)

# BGP routing parameters

**.bgpRouting.updateInterval = 30s

  1. Traffic Configuration:
    • Set up application-level traffic amongst hosts to generate network activity, accelerating BGP route advertisements and updates.

Step 6: Run the Simulation

  1. Compile the Project:
    • Ensure everything is decorously executed and compiled.
  2. Run Simulations:
    • Implement the simulations using OMNeT++’s IDE or command line. Keen on how the BGP routing protocol performs in different conditions.

Step 7: Analyze the Results

  1. Monitor BGP Behavior:
    • Evaluate how BGP sessions are conventioned and maintained, and how routes are exchanged flanked by peers.
  2. Evaluate Performance:
    • Analyze key performance metrics like convergence time, routing stability, and packet delivery ratio.
    • Scalars and Vectors: Use OMNeT++ tools to record and analyze scalar and vector data includes the amount of routes transferred, convergence times, and packet delivery statistics.
  3. Check for Issues:
    • Look for issues like routing loops, route flapping, or slow convergence that could point out problems with the BGP implementation.

Step 8: Refine and Optimize the Protocol

  1. Address Any Issues:
    • Refine the BGP routing logic based on the simulation results to optimize performance and address any problems.
  2. Optimize for Performance:
    • Adjust the parameters like update intervals, BGP policies, or route selection criteria to increase network efficiency.
  3. Re-Test:
    • To evaluate the developments, we have to run the simulation again using enhanced protocol.

Finally, we offered the comprehensive approach of the simulation set up and implement the BGP routing with the help of INET framework in the OMNeT++. For further queries, you can reach out to us.omnet-manual.com will share with you best performance analysis related to your research work.

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