How to Implement ISP protocols in ns3

To implement Internet Service Provider (ISP) protocols in ns-3, we need to follow several steps as it is complex. ISP protocols consists on handling various aspects of network management, routing, and service delivery, so it will be a complex process. Here the given below steps will guide to implement to create a basic example that typically used in ISP networks, such as BGP for inter-domain routing and OSPF for intra-domain routing.

Step-by-Step Guide to Implementing ISP Protocols in ns-3

1. Set Up Your Environment

Ensure that ns3 is installed on the system.

2. Create a New ns-3 Module (if necessary)

If we are creating a custom protocols or helper, we might need to create a new module. but, for BGP and OSPF we can use the existing modules that are available in the ns3 or can extend them.

3. Set Up the Network Topology

Create a simulation script in the scratch directory to set up an ISP network using BGP and OSPF.

4. Implementing the Topology with BGP and OSPF

Here’s an example script to set up a simple ISP network with BGP and OSPF.

#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-global-routing-helper.h”

#include “ns3/ipv4-address-helper.h”

using namespace ns3;

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

{

CommandLine cmd;

cmd.Parse (argc, argv);

// Create nodes

NodeContainer routers;

routers.Create (4);

NodeContainer as1Nodes = NodeContainer (routers.Get (0), routers.Get (1));

NodeContainer as2Nodes = NodeContainer (routers.Get (2), routers.Get (3));

NodeContainer interAsNodes = NodeContainer (routers.Get (1), routers.Get (2));

// Set up point-to-point links

PointToPointHelper pointToPoint;

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

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

NetDeviceContainer devices;

devices = pointToPoint.Install (as1Nodes);

devices = pointToPoint.Install (as2Nodes);

devices = pointToPoint.Install (interAsNodes);

// Install the internet stack on nodes

InternetStackHelper stack;

stack.Install (routers);

// Assign IP addresses to the devices

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer if1 = address.Assign (devices.Get (0));

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

Ipv4InterfaceContainer if2 = address.Assign (devices.Get (1));

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

Ipv4InterfaceContainer if3 = address.Assign (devices.Get (2));

// Enable OSPF

Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

// Set up BGP between AS1 and AS2

// Note: This is a simplified example. BGP configuration in ns-3 would require implementing BGP sessions and updates.

Ptr<Ipv4> ipv4_1 = routers.Get (1)->GetObject<Ipv4> ();

Ptr<Ipv4> ipv4_2 = routers.Get (2)->GetObject<Ipv4> ();

Ipv4StaticRoutingHelper ipv4RoutingHelper;

Ptr<Ipv4StaticRouting> staticRouting1 = ipv4RoutingHelper.GetStaticRouting (ipv4_1);

staticRouting1->AddNetworkRouteTo (Ipv4Address (“10.1.2.0”), Ipv4Mask (“255.255.255.0”), Ipv4Address (“10.1.3.2”), 1);

Ptr<Ipv4StaticRouting> staticRouting2 = ipv4RoutingHelper.GetStaticRouting (ipv4_2);

staticRouting2->AddNetworkRouteTo (Ipv4Address (“10.1.1.0”), Ipv4Mask (“255.255.255.0”), Ipv4Address (“10.1.3.1”), 1);

 

// Set up applications (e.g., a UDP echo server and client)

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (routers.Get (3));

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (if3.GetAddress (1), 9);

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

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

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

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

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

// Enable tracing

pointToPoint.EnablePcapAll (“isp-simulation”);

// Run the simulation

Simulator::Run ();

Simulator::Destroy ();

return 0;

}

5. Build and Run the Simulation

After writing the script, we need to build and run it.

./waf build

./waf –run scratch/isp-simulation

6. Analyze the Results

After running the simulation, we can analyze the results using the generated pcap files (isp-simulation-0-0.pcap, etc.).

Explanation

1. Topology Setup: We had created a simple topology with four routers that represents two autonomous systems (AS1 and AS2) which are connected by a link.
2. Point-to-Point Links: We set up point-to-point links between the routers.
3. Internet Stack: We install the internet stack on all routers.
4. IP Address Assignment: We assign IP addresses to each link.
5. OSPF Configuration: We enable OSPF using the global routing helper.
6. BGP Configuration: This is a simplified example. For actual BGP, we need to implement BGP sessions and update exchanges.
7. Applications: We set up a UDP echo server and client to test connectivity.
8. Tracing: We enable pcap tracing to capture packets for analysis.

Finally, we all get to know how to implement the two complex protocols BGP (inter-domain routing) and OSPF (intra-domain routing) which are typically found in ISP networks using the existing module in ns3 tool.

Approach us to get best results for BGP (inter-domain routing) and OSPF (intra-domain routing) implementation work.