how-to-begin-implement-a-mpls-protocol-in-ns3

To begin executing the Multiprotocol Label Switching (MPLS) protocol utilising NS3 which needs to make or replicate the MPLS functionalities like label distribution, switching, and forwarding. MPLS isn’t directly executed within ns3, but we will want to replicate their behavior by integrating routing and switching aspects, or by prolonging ns3 including custom logic. The below is the detailed procedure on how to start and execute the MPLS in ns3:

Steps to Begin Implement a MPLS Protocol in NS3

1. Understand MPLS Protocol

• Key Components:
  • Label-Switched Path (LSP): A pre-established path to transmit the packets.
  • Label Distribution: To allocate labels to packets.
  • Forwarding Equivalence Class (FEC): Clustering packets, which are handled the similar way.
  • Label Switch Routers (LSRs): According to the labels, it transmits packets.
  • Ingress/Egress Routers: Integrate/eliminate the MPLS labels on the network edges.

2. Set Up ns3 Environment

1. Install ns3:
   • We should download and install ns3 on the system.
   • Make sure we have installed NS3 by executing a simple instance: ./waf –run hello-simulator.
2. Include Required Modules:
   • Allow all necessary modules such as internet, point-to-point, and applications.

3. Define Network Topology

1. Create Nodes:
   • Describe nodes with routers and hosts within the network.

NodeContainer routers, hosts;

routers.Create(4); // MPLS-enabled routers

hosts.Create(2);   // End hosts

1. Establish Links:
   • Associate routers and hosts with PointToPointHelper.

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“10Mbps”));

p2p.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer routerLinks1 = p2p.Install(routers.Get(0), routers.Get(1));

NetDeviceContainer routerLinks2 = p2p.Install(routers.Get(1), routers.Get(2));

NetDeviceContainer routerLinks3 = p2p.Install(routers.Get(2), routers.Get(3));

NetDeviceContainer hostToRouter1 = p2p.Install(hosts.Get(0), routers.Get(0));

NetDeviceContainer hostToRouter2 = p2p.Install(hosts.Get(1), routers.Get(3));

1. Install Network Stack:
   • Integrate the network stack to routers and hosts.

InternetStackHelper internet;

internet.Install(routers);

internet.Install(hosts);

1. Assign IP Addresses:
   • Allocate an unique IP addresses to utilize Ipv4AddressHelper.

Ipv4AddressHelper ipv4;

ipv4.SetBase(“10.1.1.0”, “255.255.255.0”);

ipv4.Assign(routerLinks1);

ipv4.SetBase(“10.1.2.0”, “255.255.255.0”);

ipv4.Assign(routerLinks2);

ipv4.SetBase(“10.1.3.0”, “255.255.255.0”);

ipv4.Assign(routerLinks3);

ipv4.SetBase(“10.1.4.0”, “255.255.255.0”);

ipv4.Assign(hostToRouter1);

ipv4.SetBase(“10.1.5.0”, “255.255.255.0”);

ipv4.Assign(hostToRouter2);

4. Simulate MPLS Behavior
5. Label Assignment and Forwarding

1. Ingress Router:
   • Allocate an MPLS label to packets which going into the MPLS domain.
   • Mimic label insertion to leverage a custom header such as MplsHeader.
2. LSRs (Intermediate Routers):
   • Depends on the MPLS label, we can send packets.
   • Apply a label-to-FEC mapping that executed through lookup tables.
3. Egress Router:
   • Before sending packets to the end node, eliminate the MPLS labels.

Example: Custom MPLS Header

Describe an MPLS header for denoting labels:

class MplsHeader : public Header {

private:

uint32_t label;

public:

MplsHeader(uint32_t l = 0) : label(l) {}

void SetLabel(uint32_t l) { label = l; }

uint32_t GetLabel() const { return label; }

void Serialize(Buffer::Iterator start) const override {

start.WriteHtonU32(label);

}

uint32_t Deserialize(Buffer::Iterator start) override {

label = start.ReadNtohU32();

return sizeof(uint32_t);

}

uint32_t GetSerializedSize() const override { return sizeof(uint32_t); }

void Print(std::ostream &os) const override { os << “Label: ” << label; }

};

1. Custom Routing Logic

Execute custom logic sending packets according to the MPLS labels:

• Fine-tune Ipv4RoutingProtocol for replicating MPLS label swapping.
• For preconfigured paths, we need to utilize AddHostRouteTo or AddNetworkRouteTo.

Ptr<Ipv4StaticRouting> staticRouting = routingHelper.GetStaticRouting(routers.Get(1)->GetObject<Ipv4>());

staticRouting->AddHostRouteTo(Ipv4Address(“10.1.5.1”), Ipv4Address(“10.1.3.2”), 1);

5. Install Applications

1. Simulate Traffic:
   • Make traffic among the hosts with the support of a UDP or TCP application.

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApps = echoServer.Install(hosts.Get(1)); // Server at Host 2

serverApps.Start(Seconds(1.0));

serverApps.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(Ipv4Address(“10.1.5.1”), 9); // Client at Host 1

echoClient.SetAttribute(“MaxPackets”, UintegerValue(10));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(1.0))); // Send every second

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

ApplicationContainer clientApps = echoClient.Install(hosts.Get(0));

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(10.0));

1. Monitor Traffic:
   • Seize received packets applying the PacketSink for observing traffic.

PacketSinkHelper sinkHelper(“ns3::UdpSocketFactory”,

InetSocketAddress(Ipv4Address::GetAny(), 9));

ApplicationContainer sinkApps = sinkHelper.Install(hosts.Get(1));

sinkApps.Start(Seconds(1.0));

sinkApps.Stop(Seconds(10.0));

6. Enable Tracing

1. PCAP Tracing:
   • Seizure packet traces of PCAP for detailed analysis.

p2p.EnablePcapAll(“mpls-simulation”);

1. ASCII Tracing:
   • Record all routing events.

AsciiTraceHelper ascii;

p2p.EnableAsciiAll(ascii.CreateFileStream(“mpls-simulation.tr”));

1. FlowMonitor:
   • Estimate the performance parameters such as delay and throughput to leverage FlowMonitor.

FlowMonitorHelper flowmon;

Ptr<FlowMonitor> monitor = flowmon.InstallAll();

7. Run the Simulation

1. Start the Simulation:

Simulator::Run();

Simulator::Destroy();

1. Export Results:
   • We must store FlowMonitor outcomes for in-depth analysis.

monitor->SerializeToXmlFile(“mpls-results.xml”, true, true);

8. Analyze and Visualize Results

1. Traffic Analysis:
   • Estimate the label switching, latency, and throughput to utilize PCAP files and FlowMonitor for traffic analysis.
2. NetAnim Visualization:
   • Transfer the simulation to apply NetAnim tools for envisioning MPLS routing.

AnimationInterface anim(“mpls-simulation.xml”);

9. Extend and Optimize

1. Dynamic LSP Setup:
   • Execute dynamic LSP creation to utilize signaling protocols such as RSVP-TE or LDP.
2. QoS Integration:
   • Give precedence to traffic with MPLS according to the QoS needs.
3. Scalability:
   • Experiment the MPLS performance within large-scale networks to measure scalability.

Example Use Cases

• Service Provider Networks:
  • Experiment MPLS within large networks for traffic engineering.
• Enterprise Networks:
  • Assess MPLS-based VPN results in enterprise networks.
• QoS Routing:
  • For bandwidth reservation and priority traffic, we need to use MPLS.

Here, we had clearly discussed about how we design or simulate the MPLS functionalities using step-by-step techniques in NS3 environment that were implemented. If you need any other information regarding this MPLS protocol we will support and provide it.