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Use Network Emulation to Create Real-World Conditions


Key takeaways:

We're seeing rapid advances in all areas of networking. Commercial wired networks are approaching terabit-per-second speeds. Mobile 5G networks are available in previously unreachable locations, thanks to non-terrestrial networks. 6G networks are expected to have very low latencies. Militaries around the world are aiming for highly connected soldiers and equipment. There's talk of software-defined vehicles and automotive networks.

As each of these technologies advances, engineers who are researching, developing, and testing them need to create all the real-world network conditions they may encounter. One of the most versatile approaches for creating real-world network conditions is network emulation.

This blog explores network emulation, its use cases in various industries, and Keysight's solutions for emulating all types of networks.

What is the purpose of network emulation in networking?

Emulation's goal is to create real-world network environments to help test network equipment, user devices, applications, functionalities, and overall end-user experiences. An emulator is inexpensively, and often temporarily, physically inserted between network segments or devices of a production or test network to create real-world network impairments related to bandwidths, throughputs, latencies, packet losses, and other core characteristics.

Through emulation, network engineers can study the emergent behavior, performance, and quality of end-user experience of the real-world network, its nodes, and the software on them while realistic data passes through the network under realistic loads.

The illustrations below show some concrete use cases of network emulation.

The first example is an emulated link to a remote office on another continent to check the network performance and video quality of a corporate video conferencing software.

Test Video Conferencing With Emulated Intercontinental Network Link | Corporate Network Video Conferencing Illustration

Fig 1. Test video conferencing with emulated intercontinental network link

The second example below shows a carrier emulating a wireless link between a smartphone and a non-terrestrial 5G network to test mobility and call quality.

Emulated Mobile Network Links | 5G Mobile Network Use Case Short Distance Real Rf

Fig 2. Emulated mobile network links

Emulation creates realistic network conditions in a physical network link. The nodes connected by these links are often part of some production or test network. Crucially, the nodes themselves are not emulated in any way. The focus of emulation is entirely on the links between them.

Examples of nodes include computers, routers, firewalls, mobile devices, mobile network base stations, applications, and internet of things (IoT) devices. Each node can either be a physical device (like a rack server or a smartphone) or a virtualized device (like a virtual machine from a public cloud provider).

How does network emulation differ from simulation and other testing methods?

We can understand network emulation even better by comparing it with other common approaches prevalent in test environments. However, it's crucial to remember that all these approaches are complementary and compatible rather than exclusionary. They can be, and often are, used simultaneously for testing different aspects of the same network.

Network emulation vs. simulation

A network simulator is useful for modeling a network without any need for physical devices or networks.

A network emulator helps test a physical network by inserting itself between two network segments or devices and introducing controlled network conditions like latency, faults, packet loss, and other impairments to emulate real-world scenarios.

Network emulation vs. traffic generation

Traffic generation complements emulation. While emulation mimics the connections between nodes, traffic generation mimics the real-world data and loads sent and received by the nodes.

Network emulation vs. latency testing

Latency testing is done by manipulating the packets on real network connections. In contrast, network emulation creates latency when it's physically inserted in a link between two network segments or devices.

Network emulation vs. fault injection

Like latency testing, fault injection manipulates the packets on real network connections. Network emulation creates faults when it's physically inserted in a link between two network segments or devices.

Network emulation vs. virtualization

Virtualization is a foundational technology on which emulation relies heavily. However, emulation is not the only use case enabled by virtualization. Other use cases of virtualization include:

What types of networks and scenarios can be emulated using network emulation tools?

Although emulation is used for testing local area network (LAN) scenarios, they are far more valuable when testing wide area networks (WANs) because their network topologies can be complex and expensive to physically set up. In the following sections, we list some practical WAN network configurations where emulation can help.

Long-distance wired networks

Underground and submarinefiber optic cables are the backbone of the global internet. Almost all national, public, private, and corporate networks communicate with each other through this backbone. Some common scenarios that can be emulated include:

Data center networks

Emulation is useful for validating the reliability and performance of remote storage and disaster recovery use cases like:

Defense networks

Real-time performance and reliability are crucial for defense and battlefield networks under conditions that may be far from ideal due to distance, weather, or subversive activities of enemy forces. Emulation allows the recreation of such conditions to test the resiliency of these networks.

Mobile networks

Emulation is a critical tool in mobile 4G/5G/6G network testing because of the large number of possible scenarios. Ensuring reliable application performance during voice and video calling, good end-user experiences, and high mobile data bandwidth are important.

Emulators can test scenarios like increased latency in non-terrestrial networks due to Doppler shifts of fast-moving satellites.

Emulation is also essential for validating the reliability of cellular IoT networks like 5G RedCap that are used in critical remote infrastructure like oil and gas rigs.

Other wireless networks

Emulation is useful for validating other wireless networks like vehicle-to-everything (V2X) networks and Wi-Fi networks that are difficult and expensive to physically set up.

What are the key features and capabilities of modern network emulation tools?

Some of the key impairment capabilities of tools like Keysight's Network Emulator 3 for Ethernet-based emulated networks include:

How are real-world conditions, such as latency and packet loss, simulated in network emulation?

Keysight Network Emulator 3 Device in a Test Environment | Generator Analyzer Test System Flowchart

Fig 3. Keysight Network Emulator 3 device in a test environment

Network emulators can create realistic network conditions using dedicated hardware.

When traffic flows through the emulator's input port, the following steps happen (at a minimum):

To emulate a wireless network (like the access network between a smartphone and a 5G base station), it must do three steps:

  1. Capture the transmitted radio frequency (RF) signals: Using over-the-air (OTA) test equipment like anechoic chambers, the emulator receives RF signals from the transmitting endpoints.
  2. Generate new RF signals: New RF signals are generated based on the emulator configuration.
  3. Retransmit the new RF signals: The emulator then transmits these generated RF signals to the destination device kept in an OTA chamber.

How does network emulation contribute to the development and testing of new network technologies?

Emulation is an important tool in developing new technologies for optical networks, telecommunications, automotive in-vehicle networks, defense and aerospace networks, and other networked domains. It contributes through benefits like:

What challenges are associated with implementing effective network emulation in diverse environments?

Some of the challenges of realistic network emulation are outlined below:

How is network emulation used in the context of cybersecurity testing and training?

Keysight Exata Network Modeling and Emulation Software | Screenshot of Software

Fig 4. Keysight EXata network modeling and emulation software

Some specialized tools like Keysight's EXata Cyber Attack Emulator support advanced emulation capabilities required for cybersecurity testing. They include:

Boost Your Systems With Keysight Network Emulation

Keysight Network Emulator 3 | Network Emulation Machine

Fig 5. Keysight Network Emulator 3

In this article, we explored various aspects and use cases of network emulation.

Keysight's network emulation hardware and wireless emulators enable you to accurately model a wide variety of wired and wireless network conditions in your design and verification labs. Software like EXata allows multidomain network modeling and emulation.

Contact us for insights on how you can integrate these solutions into your existing workflows for streamlining and troubleshooting your networks.

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