NetHang: The Precision Network Environment Simulator for Real-World Quality Testing

The Critical Role of Last-Mile Network Quality

In modern internet applications, the quality of network links between user terminals and servers has become a decisive factor in service experience. Whether for video conferencing, online gaming, or real-time financial transactions, fluctuations in the last-mile network often create service quality bottlenecks. Traditional network simulation tools primarily target data centers or backbone networks, while NetHang fills the technical gap in simulating real user-terminal network environments.

Network Topology

Core Positioning of NetHang

NetHang is specifically engineered for simulating terminal-to-server link quality, accurately replicating complex real-world network scenarios:

  1. User Equipment → Local Network → Router → ISP Edge Node → Application Server
  2. Mobile Device → Cellular Network → ISP Edge Node → Application Server
  3. Satellite Terminal → Air Interface → Satellite Relay → Application Server

Through its visual interface and YAML configuration, developers can construct network impairment models tailored to specific scenarios. This eliminates the need for physical test environments when evaluating application performance under weak network conditions.

In-Depth Analysis of Core Features

1. End-to-End Traffic Control

graph LR
    A[User Equipment] --> B[Uplink Control]
    B --> C[Latency/Packet Loss]
    C --> D[Server]
    D --> E[Downlink Control]
    E --> A
  • Bi-directional Traffic Shaping: Independent control of uplink/downlink bandwidth
  • Precision Latency Simulation: Fixed delay + dynamic jitter configuration
  • Intelligent Packet Loss Models: Configurable random or burst loss patterns

2. Visual Data Comparison

Data Flow Comparison

NetHang’s real-time dashboard visually displays:

  • Comparative curves of raw vs. simulated traffic
  • Active network parameter states
  • Packet-level transmission path analysis

3. Extensible Model Architecture

# Custom 4G Network Profile
network_profile:
  name: "4G_Urban"
  latency: 
    base: 50ms 
    jitter: ±20ms
  packet_loss: 0.5%
  bandwidth:
    uplink: 10Mbps
    downlink: 50Mbps
  characteristics:
    - burst_loss_pattern: [100ms, 200ms]

Technical Implementation Principles

NetHang leverages Linux kernel’s traffic control subsystem:

  1. tc (Traffic Control): Bandwidth throttling and queue management
  2. netem Module: Network impairment functions (latency/loss/reordering)
  3. iptables: Rule-based packet marking and routing

This architecture ensures high precision with low resource overhead, supporting gigabit-level traffic simulation on single nodes.

Installation and Deployment Guide

System Requirements

  • OS: Linux (Kernel 4.15+)
  • Dependencies: tc, iptables, Python 3.8+
  • Permissions: Root access for traffic control operations

Installation Steps

PyPI Installation (Recommended):

pip install nethang

Source Installation (Developers):

git clone https://github.com/stephenyin/NetHang.git
cd NetHang
pip install .

Quick Start

sudo nethang start -c ./profiles/mobile_network.yaml

Access the web interface at http://localhost:8080 for real-time monitoring and parameter adjustment

Real-World Application Scenarios

Real-Time AV Optimization

  • Simulating 4G/5G fluctuations across regions
  • Testing packet loss recovery algorithms
  • Optimizing adaptive bitrate switching thresholds

Cloud Gaming Experience Testing

pie
    title Network Impact on Cloud Gaming
    “Latency Sensitivity” : 45
    “Frame Rate Fluctuation” : 30
    “Input Delay” : 20
    “Quality Degradation” : 5
  • Replicating high-latency control feedback
  • Assessing visual quality under packet loss
  • Validating edge computing deployments

IoT Device Validation

  • Satellite link high-latency scenarios
  • NB-IoT narrowband data transmission
  • Device reconnection mechanisms in weak networks

Engineering Value Proposition

  1. Cost Efficiency: Replaces expensive hardware network emulators
  2. Time Savings: Minute-scale test environment creation
  3. Scenario Coverage: Custom extreme network conditions
  4. Result Reproducibility: YAML-configurable test consistency

Open Source Ecosystem

Licensed under MIT, NetHang encourages community collaboration:

  1. Plugin architecture for functional extensions
  2. CI/CD pipeline integration for automated testing
  3. Python API for custom development
# Automation Script Example
import nethang
controller = nethang.Controller()
controller.load_profile('satellite_link.yaml')
controller.run_test(duration=300)
controller.generate_report()

Future Development Roadmap

  1. ML-powered intelligent impairment prediction
  2. Real-network data modeling imports
  3. Containerized deployment support
  4. Multi-node distributed simulation

Conclusion

NetHang pioneers software-defined network impairment to deliver cost-effective terminal network simulation. Its out-of-the-box functionality lowers barriers to network quality testing, while its extensible architecture meets professional-grade requirements. For internet applications with increasingly stringent real-time demands, such tools are becoming essential infrastructure for quality enhancement.

Project Repository: https://github.com/stephenyin/NetHang
Documentation: Run nethang --help for CLI reference