How to Develop Benes Network Routing Projects Using NS3

To develop Benes network routing in NS3, it is a multistage interconnection network which often utilized for high-speed switching, data center networking, and parallel computing systems. It has two back-to-back Butterfly networks and provides supports for rearrange able non-blocking switching.

We will design a custom module for routing within a Benes network as NS3 doesn’t have inherent support for Benes networks.

Steps to Develop Benes Network Routing Projects in NS3

  1. Understanding Benes Network Structure

A Benes Network contains:

  • N Input Nodes
  • N Output Nodes
  • Switching Elements (2×2) for Routing Decisions
  • 2 log(N) – 1 Switching Stages

For an 8×8 Benes Network, we need 3 stages like:

  1. Stage 1: Direct links from input nodes.
  2. Stage 2: Middle switching layer.
  3. Stage 3: Output connections.
  1. Install and Set Up NS3

We should install NS3 environment. If not, we follow these steps:

git clone cd ns-3-dev

./ns3 configure –enable-examples –enable-tests

./ns3 build

  1. Define an 8×8 Benes Network Topology

We need to utilize NS3 nodes and point-to-point links for defining an 8×8 Benes network.

(A) Create Nodes

NodeContainer inputNodes, stage1Nodes, stage2Nodes, stage3Nodes, outputNodes;

uint32_t N = 8;  // Number of input and output nodes

inputNodes.Create(N);

stage1Nodes.Create(N);

stage2Nodes.Create(N);

stage3Nodes.Create(N);

outputNodes.Create(N);

(B) Connect Stages Using Point-to-Point Links

In Benes network, every single 2×2 switch links to nodes at diverse stages.

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“1Gbps”));

p2p.SetChannelAttribute(“Delay”, StringValue(“1ms”));

std::vector<NetDeviceContainer> deviceLinks;

// Connect Input to Stage 1

for (uint32_t i = 0; i < N; i++) {

deviceLinks.push_back(p2p.Install(inputNodes.Get(i), stage1Nodes.Get(i / 2)));

}

// Connect Stage 1 to Stage 2

for (uint32_t i = 0; i < N / 2; i++) {

deviceLinks.push_back(p2p.Install(stage1Nodes.Get(i), stage2Nodes.Get(i * 2)));

deviceLinks.push_back(p2p.Install(stage1Nodes.Get(i), stage2Nodes.Get(i * 2 + 1)));

}

// Connect Stage 2 to Stage 3

for (uint32_t i = 0; i < N / 2; i++) {

deviceLinks.push_back(p2p.Install(stage2Nodes.Get(i), stage3Nodes.Get(i / 2)));

}

// Connect Stage 3 to Output

for (uint32_t i = 0; i < N; i++) {

deviceLinks.push_back(p2p.Install(stage3Nodes.Get(i / 2), outputNodes.Get(i)));

}

  1. Assign IP Addresses

InternetStackHelper stack;

stack.Install(inputNodes);

stack.Install(stage1Nodes);

stack.Install(stage2Nodes);

stack.Install(stage3Nodes);

stack.Install(outputNodes);

Ipv4AddressHelper address;

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

for (auto& link : deviceLinks) {

address.Assign(link);

}

  1. Implement Benes Network Routing Algorithm

(A) Create a Custom Benes Routing Class

class BenesRoutingProtocol : public Ipv4RoutingProtocol {

public:

void RoutePacket(Ptr<Packet> packet, Ipv4Address destination);

};

(B) Implement Benes Routing Logic

Benes routing have need of precomputed switching paths.

void BenesRoutingProtocol::RoutePacket(Ptr<Packet> packet, Ipv4Address destination) {

uint32_t srcIndex = packet->GetUid() % 8;

uint32_t dstIndex = destination.Get();

NS_LOG_UNCOND(“Routing packet from ” << srcIndex << ” to ” << dstIndex);

if (srcIndex < 4) {

NS_LOG_UNCOND(“Forwarding via upper path.”);

} else {

NS_LOG_UNCOND(“Forwarding via lower path.”);

}

}

(C) Apply Benes Routing to Nodes

Ptr<BenesRoutingProtocol> benesRouting = CreateObject<BenesRoutingProtocol>();

inputNodes.Get(0)->AggregateObject(benesRouting);

  1. Setup Traffic Applications

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApps = echoServer.Install(outputNodes.Get(7));

serverApps.Start(Seconds(1.0));

serverApps.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(Ipv4Address(“10.1.1.7”), 9);

echoClient.SetAttribute(“MaxPackets”, UintegerValue(5));

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

echoClient.SetAttribute(“PacketSize”, UintegerValue(512));

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

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(10.0));

  1. Enable Tracing for Debugging

For debugging, analyse the performance by tracing

AsciiTraceHelper ascii;

p2p.EnableAsciiAll(ascii.CreateFileStream(“benes-routing.tr”));

p2p.EnablePcapAll(“benes-routing”);

  1. Run the Simulation

Then, we can execute the simulation using

Simulator::Run();

Simulator::Destroy();

  1. Analyze Results

Envision the performance outcomes using NetAnim:

./waf –run benes-routing

netanim

  1. Extend with Advanced Features
  • Dynamic Routing in Benes Networks: Enable path reconfiguration in the networks.
  • QoS-aware Benes Routing: Give precedence to low-latency paths.
  • Fault-Tolerant Routing: Execute the failure detection and rerouting.

Throughout this guide, Benes Network Routing projects’ approach has been explained in sequence for developing and examining it using NS3 simulator and we’re furnished to deliver more in-depth insights if requested.