By Matt Kutchins, Structured Senior Network Engineer —

Virtualization revolutionized IT networking, making switches and routers almost as powerful as servers. It facilitates running containers and virtual machines directly on switches to maximize hardware utilization, streamline operations and enhance security.

Meanwhile, network simulation tools help IT engineers working in virtualized environments by providing a cost-effective and risk-free way to design, test and optimize networks before deployment in a production environment. They even help boost cybersecurity by enabling engineers to simulate threats, intrusion attempts, and disaster recovery scenarios to enhance network security and resilience.

So whether you work at a small business looking to optimize resources or a large enterprise seeking agility, virtualization offers a flexible solution to meet evolving IT demands. With the addition of network simulation platforms, even the smallest shops get change control to determine the behavior a networking alteration may have before it goes live.

Common Network Simulation Platforms

In this blog, we’ll explore the benefits and drawbacks of some notable platforms that facilitate network design, experimentation and performance analysis. They include:

• Eve-NG: Known for its flexibility and support for a wide range of network devices.
• ContainerLab: Offers container-based network labs, making it lightweight and efficient.
• Cisco Modeling Labs (CML): Provides a robust environment for simulating Cisco networks.
• GNS3: A well-known and user-friendly platform that supports a variety of network devices.

Network Simulation Tools: The Pros and Cons

Here is a deeper discussion of each network simulation platform listed above.

Eve-NG (Emulated Virtual Environment Next Generation)

• Pros:
  • Comprehensive Device Support: Eve-NG supports a wide range of virtualized devices from different vendors, including Cisco, Juniper, HPE Aruba and even virtual firewalls.
  • Centralized Web Interface: The web-based interface is user-friendly and simplifies the management of lab topologies.
  • Collaboration: Multiple users can collaborate on the same topology, which is useful for team-based projects or training environments.
  • Multi-Platform Support: Runs natively on Linux and is available as a virtual machine for VirtualBox, VMware Workstation, and others.
• Cons:
  • Resource Intensive: Can require significant CPU and RAM, especially when running multiple devices in complex topologies.
  • License Costs for Advanced Features: The community version is free but does not include all of the available features in the Pro version.

ContainerLab

• Pros:
  • Containerized Environment: As the name suggests, it leverages Docker containers to emulate networking gear, which makes it lightweight compared to other options.
  • Modern, Flexible: It’s more flexible in handling cloud-native networking setups and microservices.
  • Speed and Efficiency: Faster boot times and more efficient use of system resources when compared to traditional virtualization platforms.
  • Great for Cloud-Native Networks: It’s great for labs focused on SDN (Software-Defined Networking), NFV (Network Function Virtualization), or cloud-native environments.
• Cons:
  • Limited Vendor Support: While ContainerLab supports various network devices, it doesn’t have as broad vendor support as Eve-NG or GNS3.
  • Complex Setup: Setting it up may be a bit more technical, as it requires understanding Docker and container-based networking.
  • No GUI: Unlike some other platforms, ContainerLab is command-line-based and lacks the graphical interface that many users prefer.

Cisco Modeling Lab (CML)

• Pros:
  • Cisco-Focused: Best suited for those working in environments heavily reliant on Cisco hardware and software.
  • High-Fidelity Emulation: It uses real Cisco images, which means that the lab experience is very close to a production network.
  • Advanced Features: CML supports advanced features such as testing network designs, routing protocols, and more complex network setups.
• Cons:
  • Limited Vendor Support: It is heavily focused on Cisco devices, so you may not get the same level of flexibility for other vendor devices.
  • Cost: Cisco Modeling Lab is not free, and the licensing costs can be quite high, especially for smaller organizations or individual users.
  • Resource-Intensive: Like Eve-NG, CML can be demanding in terms of hardware requirements.

GNS3 (Graphical Network Simulator)

• Pros:
  • Wide Device Support: GNS3 is quite popular and supports a wide variety of devices from multiple vendors like Cisco, Juniper, and even some firewalls and other appliances.
  • Graphical Interface: GNS3 provides a highly interactive and graphical interface, making it easier for engineers to visualize and manage their network topologies.
  • Community-Driven: It has a large, active community with lots of free resources, tutorials, and templates.
  • Virtualization of Physical Devices: GNS3 can virtualize real physical devices (e.g., routers, switches) by connecting virtual devices to physical interfaces, making it more flexible in real-world labs.
• Cons:
  • Resource Heavy: GNS3 can be very demanding on system resources, especially when you are running complex topologies or using virtual machines.
  • Initial Setup Can Be Complex: Getting all components working seamlessly (e.g., Cisco IOS images, virtual machines, and network adapters) can be tricky for beginners.
  • Not Fully Scalable for Large Networks: GNS3 can become slow and unresponsive with too many devices or heavy configurations.

The Adaptability of Network Simulation Tools

Whether you’re repurposing older hardware, leveraging newer systems, or deploying within existing virtualized environments, these network simulation platforms can be adapted to meet a wide range of needs. Here are a few additional points to consider about how each of these systems can integrate with physical hardware and virtualized environments.

Repurposing Older or Newer Hardware

• Eve-NG, GNS3, Cisco Modeling Lab, and ContainerLab can all run on various hardware configurations, from older machines with sufficient RAM and CPU resources to modern, high-performance systems. This makes them cost-effective solutions for many network engineers who want to set up their own lab environments.
  • Older Hardware: For example, a system with 16GB+ of RAM and a decent multi-core processor can easily run multiple virtual devices using these platforms. If the hardware is only going to be used for light or small-scale labs, even a modest machine can work well.
  • Newer Hardware: More powerful systems can handle more complex topologies, advanced routing protocols, or virtualized instances of different network appliances. Additionally, with hardware advancements like faster SSDs and more cores, network engineers can emulate large-scale environments much faster and more efficiently.
  • Virtualization Support: Some older processors or motherboards may lack support for hardware virtualization, limiting the types of virtual machines that may be run.

Deployment in Existing Virtualized Environments

• These platforms are often used in conjunction with virtualization technologies like VMware, Hyper-V, or KVM, enabling network engineers to deploy them in environments that are already virtualized.
  • VMware/Hyper-V: Engineers can run Eve-NG, Cisco Modeling Lab, or GNS3 as virtual machines themselves on a hypervisor, utilizing the existing virtualized infrastructure. This approach allows for easier resource management, better scalability, and more efficient use of physical resources.
  • KVM/Proxmox: These platforms can also be deployed within a KVM or Proxmox virtualized environment. In fact, some network engineers prefer Proxmox for its flexibility and ability to create containerized environments or virtual machines for lab setups.

Integration with Existing Hardware

• Physical Device Integration: One of the key advantages of network virtualization is the ability to integrate virtual networks with actual hardware devices, making it more than just a virtualized setup. Both Eve-NG and GNS3, for example, allow you to connect virtual devices to physical devices like routers, switches, firewalls, or even wireless APs and phone systems.
  • For Example:
    • GNS3: It supports integration with physical devices using tools like the GNS3 VM, which can connect virtual machines with real hardware via Ethernet interfaces. This allows you to create hybrid environments where virtual and physical devices work seamlessly together. You can even run network cables to real physical routers or switches and connect them to virtual routers or firewalls, enabling end-to-end testing.
    • Eve-NG: Like GNS3, Eve-NG allows for connecting virtual devices to physical hardware, which can be useful when you want to simulate a live network environment and ensure configurations work on real devices before pushing them into production.

Creating More Robust Network Labs

• Scalable and Flexible Labs: By integrating virtualized platforms with existing hardware, network engineers can build far more robust and complex lab environments that mirror real-world network infrastructures. For example:
  • Hybrid Environments: You can mix physical and virtual devices, running production-level applications or testing critical configurations on real hardware while leveraging virtualized environments to scale and simulate additional components like routers, switches, or firewalls.
  • Advanced Testing and Automation: By using platforms like Eve-NG or GNS3, engineers can create advanced test scenarios that integrate with existing systems, automating tasks (such as configuration pushes) and testing changes in a controlled environment before deploying them live.

Cloud Integration

• In addition to physical hardware and local virtualization, these platforms can also be integrated with cloud environments like AWS, Azure, or Google Cloud. This is particularly useful for labs that need to scale rapidly or simulate hybrid cloud infrastructures.
  • For Example:
    • ContainerLab can be used in cloud-native environments or on top of Docker and Kubernetes, allowing network engineers to design and test virtual network architectures in a cloud environment with minimal physical hardware.

Final Thoughts

These platforms’ ability to be deployed on repurposed hardware, existing virtualized environments, and integrated with real-world devices makes them highly versatile for network engineers.

They allow for scalable and flexible network labs that can grow and adapt to changing needs. Whether testing small configurations on old hardware or building large-scale environments using modern cloud and virtualization technologies, these tools offer a robust solution to simulate, plan, and validate network changes with a level of flexibility that’s invaluable for modern network engineers.

Wish you could better predict how technology changes will impact your production environment? Contact your account manager or email info@structured.com if you would like to discuss which network simulation tools might be best for your organization.

About the Author

With over 30 years of IT experience, Matt Kutchins has extensive knowledge of network infrastructure design for everything from campus networking to national ISPs. He has designed and implemented access and internet connectivity services for companies of all sizes.

Proficient and knowledgeable in internet best practices and network designs utilizing both traditional Ethernet switching and newer technologies such as EVPN/VXLAN, Matt is comfortable working in technologically diverse environments. Specifically, he has significant experience with products from HPE Aruba, Palo Alto Networks, Cisco and Juniper, including ethernet switches, routers and firewalls. Matt also is highly credentialed with numerous certifications, particularly in Juniper’s JNCIP tracks.