NS-3 Routing Simulator

A configurable network routing simulator built using NS-3.48 for studying routing behavior, packet forwarding, and network performance across multiple network topologies.

This project is a port of a custom C++ routing simulator into the NS-3 ecosystem, enabling realistic packet-level simulation, performance analysis using FlowMonitor, and visualization through NetAnim.

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Features

• Multiple network topologies

  • Random Connected Graph
  • Ring Network
  • Full Mesh
  • Binary Tree

• Configurable network size

  • Tested from 20 to 500 routers

• UDP-based packet transmission

• IPv4 routing using NS-3 Global Routing

• FlowMonitor integration

• NetAnim visualization support

• Command-line configurable simulation parameters

• Docker support for reproducible builds

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Technologies Used

Component	Technology
Simulation Framework	NS-3.48
Programming Language	C++17
Build System	CMake
Visualization	NetAnim
Performance Analysis	FlowMonitor
Containerization	Docker

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Supported Topologies

Topology	Description
Random	Random connected graph
Ring	Circular chain of routers
Mesh	Fully connected network
Tree	Binary hierarchical topology

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Simulation Metrics

The simulator measures:

• Packet Delivery Ratio (PDR)
• Average End-to-End Delay
• Throughput
• Packet Loss
• Flow Statistics

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Repository Structure

ns3-Routing-Simulator/
│
├── src/
│   └── routing-sim.cc
│
├── docker/
│   └── Dockerfile
│
├── screenshots/
│
└── README.md

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Prerequisites

Install:

• NS-3.48
• CMake
• GCC/G++
• Python 3.x

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Build Instructions

Configure

./ns3 configure --enable-examples

Build

./ns3 build

Run

./ns3 run routing-sim

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Command Line Parameters

Parameter	Description	Default
--routers	Number of routers	20
--topology	random / ring / mesh / tree	random
--packets	Number of packets	100
--packetSize	Packet size (bytes)	512
--source	Source router ID	0
--destination	Destination router ID	Last Router
--dataRate	Link bandwidth	10Mbps
--linkDelay	Link delay	5ms
--randomDelay	Enable random delay	false
--delayMin	Minimum delay	1ms
--delayMax	Maximum delay	10ms
--seed	Random seed	42

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Example Commands

Random Topology

./ns3 run "routing-sim --routers=100 --topology=random"

Ring Topology

./ns3 run "routing-sim --routers=50 --topology=ring"

Mesh Topology

./ns3 run "routing-sim --routers=20 --topology=mesh"

Tree Topology

./ns3 run "routing-sim --routers=31 --topology=tree"

Custom Packet Count

./ns3 run "routing-sim --routers=100 --packets=500"

Random Link Delays

./ns3 run "routing-sim --routers=50 --randomDelay=true --delayMin=1 --delayMax=10"

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Docker Support

The simulator can be built and executed inside Docker without installing NS-3, GCC, CMake, Python, or any other dependencies locally.

Build Docker Image

docker build -t ns3-routing-simulator .

Run Default Simulation

docker run --rm ns3-routing-simulator

View Available Parameters

docker run --rm ns3-routing-simulator --help

Run with Custom Arguments

docker run --rm ns3-routing-simulator --routers=50 --topology=ring

Larger Mesh Topology Example

docker run --rm ns3-routing-simulator ^
--routers=50 ^
--topology=mesh ^
--packets=500 ^
--packetSize=1024 ^
--source=5 ^
--destination=40 ^
--randomDelay=true ^
--delayMin=5 ^
--delayMax=50

Notes

• The Docker image contains a complete NS-3 environment.
• No local installation of NS-3 is required.
• All command-line parameters are forwarded directly to the simulator.
• Use --help to view all available simulation options.

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NetAnim Visualization

The simulator generates an animation.xml file that can be opened using NetAnim.

Install NetAnim

Follow the official NS-3 documentation to install NetAnim on your system.

Open Animation

netanim

Then load:

animation.xml

Note

NetAnim is not included in the Docker image because it requires a graphical user interface (GUI). Docker is used only for simulation execution and XML generation.

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Experimental Results

Initial experiments were conducted across all supported topologies.

Topology	Routers	Packet Delivery Ratio
Random	20	100%
Ring	10	100%
Tree	15	100%
Mesh	8	100%

Key observations:

• Mesh topology achieves the lowest delay.
• Tree topology introduces higher path lengths.
• Ring topology provides deterministic routing.
• Random topology balances connectivity and scalability.
• All tested configurations achieved 100% packet delivery.

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Future Work

Potential extensions include:

• Privacy-preserving routing
• Secret-sharing based routing protocols
• Distributed routing algorithms
• Multi-path routing
• Secure forwarding mechanisms