How to implement BGP routing in ns3

To implement the Border gateway protocol (BGP) in ns3, to simulate and implemented the characteristics of BGP by making the custom routing protocol. Border gateway protocol (BGP) in ns3 you can get best implementation from ns3simulation.com. This is the path vector protocol that can interchange the data transmission among heterogeneous autonomous system (AS).

Here is the step-by-step procedure to implement the basic BGP like routing protocol in ns3:

Step-by-Step Implementation

1. Set Up ns3 Environment: To make sure that you have installed ns3 in the computer.
2. Include Necessary Libraries: To contain the essential ns3 packages in the script.
3. Define Network Topology: To make nodes and links for the network topology.
4. Install Internet Stack: Download the Internet stack on your nodes.
5. Implement the BGP Routing Protocol: Make a custom routing protocol class that simulates BGP performance.
6. Integrate the Custom Routing Protocol: Incorporate your custom routing protocol into the ns3 stack.
7. Set Up Applications: Mount applications to generate traffic and test the routing.
8. Run the Simulation: Organize the simulation parameters and run it.

Example Implementation in C++

At this direction we will provide the sample script to implement the BGP based routing protocol in ns3:

1. Include Libraries:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/point-to-point-module.h”

#include “ns3/applications-module.h”

#include “ns3/ipv4-routing-protocol.h”

#include “ns3/ipv4-list-routing-helper.h”

#include <map>

#include <vector>

2. Define Network Topology:

using namespace ns3;

int main(int argc, char *argv[]) {

CommandLine cmd;

cmd.Parse(argc, argv);

NodeContainer nodes;

nodes.Create(6);

// Define point-to-point connections

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute(“DataRate”, StringValue(“5Mbps”));

pointToPoint.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer devices01 = pointToPoint.Install(nodes.Get(0), nodes.Get(1));

NetDeviceContainer devices02 = pointToPoint.Install(nodes.Get(0), nodes.Get(2));

NetDeviceContainer devices13 = pointToPoint.Install(nodes.Get(1), nodes.Get(3));

NetDeviceContainer devices23 = pointToPoint.Install(nodes.Get(2), nodes.Get(3));

NetDeviceContainer devices34 = pointToPoint.Install(nodes.Get(3), nodes.Get(4));

NetDeviceContainer devices35 = pointToPoint.Install(nodes.Get(3), nodes.Get(5));

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper address;

address.SetBase(“10.1.1.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces01 = address.Assign(devices01);

address.SetBase(“10.1.2.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces02 = address.Assign(devices02);

address.SetBase(“10.1.3.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces13 = address.Assign(devices13);

address.SetBase(“10.1.4.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces23 = address.Assign(devices23);

address.SetBase(“10.1.5.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces34 = address.Assign(devices34);

address.SetBase(“10.1.6.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces35 = address.Assign(devices35);

3. Implement the BGP Routing Protocol:

• Create a new header file bgp-routing.h:

#ifndef BGP_ROUTING_H

#define BGP_ROUTING_H

#include “ns3/ipv4-routing-protocol.h”

#include “ns3/ipv4.h”

#include “ns3/net-device.h”

#include “ns3/ptr.h”

#include “ns3/socket.h”

#include <map>

#include <vector>

namespace ns3 {

class BgpRouting : public Ipv4RoutingProtocol {

public:

static TypeId GetTypeId(void);

BgpRouting();

virtual ~BgpRouting();

virtual Ptr<Ipv4Route> RouteOutput(

Ptr<Packet> p, const Ipv4Header &header,

Ptr<NetDevice> oif, Socket::SocketErrno &sockerr);

virtual bool RouteInput(

Ptr<const Packet> p, const Ipv4Header &header,

Ptr<const NetDevice> idev,

UnicastForwardCallback ucb, MulticastForwardCallback mcb,

LocalDeliverCallback lcb, ErrorCallback ecb);

virtual void NotifyInterfaceUp(uint32_t interface);

virtual void NotifyInterfaceDown(uint32_t interface);

virtual void NotifyAddAddress(uint32_t interface,  Ipv4InterfaceAddress address);

virtual void NotifyRemoveAddress(uint32_t interface,  Ipv4InterfaceAddress address);

virtual void SetIpv4(Ptr<Ipv4> ipv4);

void Start();

private:

void SendBgpUpdates();

void ReceiveBgpUpdates(Ptr<Socket> socket);

void UpdateRoutingTable(Ipv4Address source, std::map<Ipv4Address, uint32_t> path);

Ptr<Ipv4> m_ipv4;

std::map<Ipv4Address, std::vector<Ipv4Address>> m_routingTable;

std::map<uint32_t, Ptr<Socket>> m_socketMap;

Time m_updateInterval;

EventId m_updateEvent;

};

}

#endif // BGP_ROUTING_H

Create the corresponding implementation file bgp-routing.cc:

#include “bgp-routing.h”

#include “ns3/log.h”

#include “ns3/ipv4-routing-table-entry.h”

#include “ns3/simulator.h”

#include “ns3/inet-socket-address.h”

namespace ns3 {

NS_LOG_COMPONENT_DEFINE(“BgpRouting”);

NS_OBJECT_ENSURE_REGISTERED(BgpRouting);

TypeId BgpRouting::GetTypeId(void) {

static TypeId tid = TypeId(“ns3::BgpRouting”)

.SetParent<Ipv4RoutingProtocol>()

.SetGroupName(“Internet”)

.AddConstructor<BgpRouting>();

return tid;

}

BgpRouting::BgpRouting() : m_updateInterval(Seconds(5)) {

NS_LOG_FUNCTION(this);

Simulator::Schedule(Seconds(1.0), &BgpRouting::Start, this);

}

BgpRouting::~BgpRouting() {

NS_LOG_FUNCTION(this);

}

void BgpRouting::SetIpv4(Ptr<Ipv4> ipv4) {

NS_LOG_FUNCTION(this << ipv4);

m_ipv4 = ipv4;

}

void BgpRouting::Start() {

NS_LOG_FUNCTION(this);

SendBgpUpdates();

m_updateEvent = Simulator::Schedule(m_updateInterval, &BgpRouting::Start, this);

}

void BgpRouting::SendBgpUpdates() {

NS_LOG_FUNCTION(this);

Ptr<Packet> packet = Create<Packet>();

for (auto const &entry : m_routingTable) {

Ipv4Address source = entry.first;

for (auto const &path : entry.second) {

packet->AddHeader(Ipv4Header(source, path, 0, 0));

}

}

for (uint32_t i = 0; i < m_ipv4->GetNInterfaces(); ++i) {

Ptr<Socket> socket = m_socketMap[i];

socket->SendTo(packet, 0, InetSocketAddress(Ipv4Address::GetBroadcast(), 80));

}

}

void BgpRouting::ReceiveBgpUpdates(Ptr<Socket> socket) {

NS_LOG_FUNCTION(this);

Ptr<Packet> packet = socket->Recv();

Ipv4Header header;

packet->RemoveHeader(header);

Ipv4Address source = header.GetSource();

Ipv4Address path = header.GetDestination();

std::vector<Ipv4Address> paths;

paths.push_back(path);

UpdateRoutingTable(source, paths);

}

void BgpRouting::UpdateRoutingTable(Ipv4Address source, std::vector<Ipv4Address> paths) {

NS_LOG_FUNCTION(this << source);

for (auto const &path : paths) {

m_routingTable.push_back(path);

}

}

Ptr<Ipv4Route> BgpRouting::RouteOutput(

Ptr<Packet> p, const Ipv4Header &header, Ptr<NetDevice> oif,

Socket::SocketErrno &sockerr) {

NS_LOG_FUNCTION(this << p << header << oif << sockerr);

Ipv4Address dest = header.GetDestination();

if (m_routingTable.find(dest) == m_routingTable.end()) {

sockerr = Socket::ERROR_NOROUTETOHOST;

return 0;

}

Ptr<Ipv4Route> route = Create<Ipv4Route>();

route->SetDestination(dest);

route->SetGateway(m_routingTable[dest].front());  // Choose the first path for simplicity

route->SetOutputDevice(oif);

return route;

}

bool BgpRouting::RouteInput(

Ptr<const Packet> p, const Ipv4Header &header,

Ptr<const NetDevice> idev, UnicastForwardCallback ucb,

MulticastForwardCallback mcb, LocalDeliverCallback lcb,

ErrorCallback ecb) {

NS_LOG_FUNCTION(this << p << header << idev << ucb << mcb    << lcb << ecb);

Ipv4Address dest = header.GetDestination();

if (dest == m_ipv4->GetAddress(1, 0).GetLocal()) {

lcb(p, header, idev);

return true;

}

if (m_routingTable.find(dest) == m_routingTable.end()) {

ecb(p, header, Socket::ERROR_NOROUTETOHOST);

return false;

}

Ptr<Ipv4Route> route = Create<Ipv4Route>();

route->SetDestination(dest);

route->SetGateway(m_routingTable[dest].front());  // Choose the first path for simplicity

route->SetOutputDevice(idev);

ucb(route, p, header);

return true;

}

void BgpRouting::NotifyInterfaceUp(uint32_t interface) {

NS_LOG_FUNCTION(this << interface);

Ptr<Socket>socket=Socket::CreateSocket(GetObject<Node>(),TypeId::LookupByName(“ns3::UdpSocketFactory”));

socket->SetAllowBroadcast(true);

socket->BindToNetDevice(m_ipv4->GetNetDevice(interface));

socket->Bind(InetSocketAddress(Ipv4Address::GetAny(), 80));

socket->SetRecvCallback(MakeCallback(&BgpRouting::ReceiveBgpUpdates, this));

m_socketMap[interface] = socket;

}

void BgpRouting::NotifyInterfaceDown(uint32_t interface) {

NS_LOG_FUNCTION(this << interface);

m_socketMap[interface]->Close();

m_socketMap.erase(interface);

}

void BgpRouting::NotifyAddAddress(uint32_t interface,

Ipv4InterfaceAddress address) {

NS_LOG_FUNCTION(this << interface << address);

}

void BgpRouting::NotifyRemoveAddress(uint32_t interface,

Ipv4InterfaceAddress address) {

NS_LOG_FUNCTION(this << interface << address);

}

}

4. Integrate the Custom Routing Protocol:

#include “bgp-routing.h”

int main(int argc, char *argv[]) {

CommandLine cmd;

cmd.Parse(argc, argv);

NodeContainer nodes;

nodes.Create(6);

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute(“DataRate”, StringValue(“5Mbps”));

pointToPoint.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer devices01 = pointToPoint.Install(nodes.Get(0), nodes.Get(1));

NetDeviceContainer devices02 = pointToPoint.Install(nodes.Get(0), nodes.Get(2));

NetDeviceContainer devices13 = pointToPoint.Install(nodes.Get(1), nodes.Get(3));

NetDeviceContainer devices23 = pointToPoint.Install(nodes.Get(2), nodes.Get(3));

NetDeviceContainer devices34 = pointToPoint.Install(nodes.Get(3), nodes.Get(4));

NetDeviceContainer devices35 = pointToPoint.Install(nodes.Get(3), nodes.Get(5));

InternetStackHelper stack;

BgpRoutingHelper bgpRouting;

Ipv4ListRoutingHelper list;

list.Add(bgpRouting, 0);

stack.SetRoutingHelper(list);

stack.Install(nodes);

 

Ipv4AddressHelper address;

address.SetBase(“10.1.1.0”, “255.255.255.0”);

address.Assign(devices01);

address.SetBase(“10.1.2.0”, “255.255.255.0”);

address.Assign(devices02);

address.SetBase(“10.1.3.0”, “255.255.255.0”);

address.Assign(devices13);

address.SetBase(“10.1.4.0”, “255.255.255.0”);

address.Assign(devices23);

address.SetBase(“10.1.5.0”, “255.255.255.0”);

address.Assign(devices34);

address.SetBase(“10.1.6.0”, “255.255.255.0”);

address.Assign(devices35);

// Set up applications

uint16_t port = 9;

UdpEchoServerHelper server(port);

ApplicationContainer apps = server.Install(nodes.Get(5));

apps.Start(Seconds(1.0));

apps.Stop(Seconds(10.0));

UdpEchoClientHelper client(address.GetAddress(5), port);

client.SetAttribute(“MaxPackets”, UintegerValue(1));

client.SetAttribute(“Interval”, TimeValue(Seconds(1.0)));

client.SetAttribute(“PacketSize”, UintegerValue(1024));

apps = client.Install(nodes.Get(0));

apps.Start(Seconds(2.0));

apps.Stop(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

return 0;

}

Explanation

At this point, we provide the description of Border gateway protocol process that integrates in ns3:

1. Network Topology: The code sets up a network topology with six nodes connected in a specific configuration.
2. BGP Routing Protocol: A custom BGP-like routing protocol class (BgpRouting) is implemented. This class handles route computation and distribution based on BGP principles.
3. Route Computation: The UpdateRoutingTable method updates the routing table based on received BGP updates.
4. BGP Updates: The SendBgpUpdates method sends the current routing table to neighbors, and the ReceiveBgpUpdates method processes incoming BGP updates and updates the routing table.
5. Route Input and Output: The RouteInput and RouteOutput methods handle packet routing based on the routing table.
6. Integrate Custom Routing Protocol: The custom routing protocol is integrated into the ns3 stack using the BgpRoutingHelper.
7. Applications: UdpEchoServer and UdpEchoClient applications are set up to test the routing.

 

Running the Code

1. Save your script to a file, for example, bgp-routing.cc.
2. Compile the script using the ns3 build system

./waf configure –enable-examples

./waf build

./waf –run scratch/bgp-routing

 

Overall we had implemented the Border gateway protocol in ns3 simulation tool that can make a custom path. We provide and support all kinds of assistance about border gateway protocol. Border gateway protocol (BGP) in ns3, you can get best implementation from ns3simulation.com.