Today, technology provides companies with a competitive edge, enabling them to lower product pricing, enhance customer support, and deliver new services. But one ripple effect of new technology is that enterprise networks constantly change — so fast that it’s becoming increasingly difficult to ensure the infrastructure can keep up with business objectives. In fact, the Accenture Pulse of Change Index found the rate of change affecting businesses has risen steadily since 2019 — 183% over the past four years.
You may find your network operating fine one day, but problems arising the next day, and key opportunities are often missed. Imagine deploying a critical application only to find it lagging or failing under varied network conditions. This isn’t just an inconvenience — it’s a potential disaster that can tarnish your reputation and cost your business dearly.
Without thorough testing, the risk of encountering unforeseen latency issues increases dramatically. To address shortcomings, organizations need powerful yet flexible solutions to test and understand network and application performance. By leveraging the right network latency simulator, you can emulate your network infrastructure and latency to pinpoint needed changes and maintain performance of your business applications.
Let’s take a look at how to simulate network latency as part of your overall network testing strategy.
Network Latency Defined
Latency (also called “delay”) is the time it takes for a data packet to travel from its source, across the Wide Area Network (WAN), to its destination and back. Typically, latency is measured in milliseconds (ms).
Transmissions start at one end of a connection and travel through network devices and wiring to reach their destination. As they move from place to place, device performance fluctuates, creating bottlenecks and various slowdowns. Calculating network latency means adding up the delays at multiple points in the transmission:
- Propagation Delay: The time it takes for a signal to travel through the physical medium (e.g., fiber optic cable, copper wire).
- Processing Delay: The time taken by routers and switches to process the packet header.
- Transmission Delay: The period required to push all the packet’s bits onto and off of the wire.
- Queuing Delay: The period that a packet spends sitting in routing queues waiting to move.
For example, imagine a single data packet sent from your computer to a server. The total network latency can be calculated by adding the individual delays: propagation delay (10 ms), transmission delay (0.08 ms), processing delay (1 ms), and queueing delay (5 ms). In this example, the total latency is 16.08 milliseconds. This is a reasonable level of latency for most situations.
NOTE: This example is a simplified illustration. Real-world latency values can vary significantly depending on network conditions, distance, and specific technologies. In reality, you’ll need to account for potential asymmetries in network paths or variations in latency over time. For this reason, it’s best to use round-trip time (RTT) measurements (which include the return path) to assess overall latency.
Time is your most valuable asset, and network latency wastes a lot of time. High latency causes transmission delays, affects network and application performance, and drains productivity. It also tends to anger customers using highly network-dependent applications.
What is a Network Latency Simulator?
A network latency simulator is a tool that allows companies to emulate the delays that data packets experience (due to various conditions) as they travel across a network. These tools help developers and network engineers understand how network latency affects the performance and reliability of applications — especially in cloud-based environments.
Test data from network latency simulators can help with:
- Application performance testing
- Troubleshooting
- Development and QA
- Training
- Reporting
What Should Your Network Latency Be?
Latency impact varies by application. Some applications require an immediate response while others can take longer. There are no precise ranges for how long a transaction should take, but some broad guidelines exist for different use cases.
Web Browsing and Cloud Applications
Google Chrome and other web browsing and cloud applications are the most common use cases, making them particularly useful for web developers and QA teams to test. For these applications, latency under 100 ms is typically acceptable, and delays under 50 ms provide very satisfying user experiences.
Real-Time Applications That Require Low Latency
Stock trading, ecommerce platforms, and online gaming are a few examples of applications with very low latency thresholds. Just about any type of delay has a negative impact on the user experience, so they demand very low latency (20-50 ms at most).
Data Transfers and Backup
Applications involving large data transfers or backups are more tolerant of latency. These applications typically run for long periods of time. In this case, the company is more interested in ensuring the information is processed rather than how quickly the process takes place.
However, these applications tend to be bandwidth-intensive. Often, they run at night, so they do not interfere with other transmissions. High latency adds to processing time and can require network upgrades. So, even in this case, the ultimate goal is to keep latency low enough to not interfere with other applications.
What Causes Network Latency?
Slow connections occur for many reasons — equipment issues, distance, network infrastructure and design. The key is to understand them and develop tailored solutions.
Traffic Increases
When too many devices are trying to use the network at the same time, congestion can occur, leading to increased queueing delays and slower data transmission. However, the goal of modern networking is to create a stable infrastructure that can handle not only the expected traffic but also unexpected spikes and anomalies.
Distance
In the past, companies often had their data centers on site, so the time to pass information from the user device to the server and back was minimal. With the rise of new cloud applications, servers moved from the local data center to remote sites. As a result, information travels greater distances and demands more travel time.
Within a country or region, latency might range from 10ms to 50 ms. For international connections, delays can take from 50ms to 150 ms — and sometimes higher, depending on the distance, the number of intermediate hops, and the network equipment’s power and performance.
Network Design
Building a Wide Area Network (WAN) is a complex process involving many pieces of equipment and often multiple carriers. In some cases, firms create WANs that route traffic inefficiently, causing delays and creating user dissatisfaction.
Outsourcing
The fact that organizations do not run all the network and the WAN infrastructure themselves is yet another challenge. Many rely on telecommunications service providers who build their own networks to move information from place to place.
In some cases, they take on more customers than their infrastructure can support. As a result, a transmission may slow down as it moves through that piece of the connection.
Network Emulation/Simulation Use Cases
Many organizations have tens and often hundreds of applications relying on shared network infrastructure. Who is on the network and what they are sending over the network varies from moment to moment. But companies need to understand how the network is performing for all applications.
This is why businesses often test application performance before deployment. Running Ethernet in the lab can sometimes be helpful. With this approach, the company gets a high-level view of how much information the application creates and how well the infrastructure performs. However, the tests do not mirror real-world deployments. Sometimes, significant delays arise as the application moves from the lab to the enterprise network.
Network emulation builds a real-time model that mimics actual network behavior. They can introduce latency, jitter, packet loss, and other network impairments, mimicking real-world scenarios to test applications under the actual conditions they are most likely to encounter — without the cost burden or risk of early deployment.
Networks constantly change, so organizations must continually understand how well they are running. By comparing current performance to past performance, you can see which areas are trending positively or negatively and make necessary adjustments.
These problems tend to arise haphazardly. Sometimes, users see network degradation faster than the firm’s monitoring tools. Emulation and simulation enable companies to troubleshoot proactively, then find and remediate any performance bottlenecks before users call the help desk.
What Is Needed in a Network Latency Simulator/Emulation Solution?
Simulating latency is not simple — and it becomes more complex every day as companies extend their enterprise networks. A few features companies should look for in solutions are flexibility, support for high-speed networks, simplicity, and scalability.
Flexibility
Since each network is unique, flexibility is a must. Whatever tool you use, it needs to work for a variety of networks and support testing in different scenarios.
Just simulating network latency isn’t enough. The tool needs to be able to address varying impairments. For instance, Apposite’s Netropy Network Emulator allows you to simulate latency from 0.1 ms up to 10 seconds in a constant, normal, or uniform distribution and in either direction. In addition, customers can specify loss as either a packet loss rate, bit error rate, or both.
High-Speed Testing
The highest bandwidth links are most important because they carry the bulk of the company traffic. Users need the ability to test top speeds: Gbps.
With Netropy, you can emulate links up to 100 Gbps and determine congestion effects on bandwidth and jitter-sensitive applications to make changes if needed. You can then confirm that applications adequately handle anomalous packet reordering and duplicate conditions without creating performance or stability problems.
Ease of Use
Building and running test cases can be time-consuming and challenging. Organizations need to be able to quickly generate the necessary data. Performance tools offload test generation from individual employees.
That’s why ease of use is a key feature. Testing is no longer limited to network technicians but done by individuals in all departments. To achieve a decent ROI, emulation tools need to be simple enough to use by employees without technical skills or formal training.
Netropy has an intuitive user interface, and new users can often create test cases in just minutes.
Scalability
Organizations need the ability to examine how network conditions affect application performance over time. This requires tests that are not only repeatable but also adaptable to identify different types of problems that may arise as network size and complexity increases.
The Netropy delay emulator exemplifies scalability by offering four separate pairs of Ethernet interfaces, enabling the simulation of over 100 network links with the same ease as simulating a single link. This allows organizations to effectively test and manage large-scale network environments. Copper or SFP ports are also available for easing.
More Than a Simple Test
To get the most value out of a network latency simulator, it should do more than test latency alone. Apposite’s Netropy is the perfect solution to maximize the ROI of your application performance testing tools. In addition to simulating network latency, the solution allows you to recreate different network conditions and configurations, repeat tests, and much more.
However, if you’re looking for a simpler solution for a much smaller testing use case and lower cost, Apposite’s Linktropy is designed to simulate network latency for a single WAN link.
How To Simulate Network Latency With Netropy
Netropy’s intuitive interface makes it easy to set up and run latency tests quickly. Even new users can set up tests in just a few minutes — without special training. With high-precision network emulation, Netropy allows for accurate and repeatable results, enabling you to thoroughly evaluate application performance under various latency conditions before deployment.
Here’s how to set up a basic latency test with Netropy:
- Connect the Netropy device to your network.
- Access the Netropy web-based graphical user interface (GUI) using a standard web browser.
- In the Netropy GUI, create a new emulation scenario or select an existing one to modify.
- Configure a WAN link by specifying the desired network conditions. For latency simulation:
- Set the latency value in milliseconds. Netropy allows you to configure latency from 0.1 ms up to 10 seconds.
- Choose a distribution type for the latency: constant, normal, or uniform.
- You can set different latency values for each direction of traffic if needed.
- Adjust other network parameters as required for your test scenario, such as bandwidth constraints, packet loss, or jitter.
- Apply the settings to activate the emulation.
- Begin your application performance testing under the simulated network conditions.
- Monitor the traffic and network statistics in real-time using Netropy’s built-in graphing and reporting tools.
- Modify the latency settings or other parameters as needed during the test to observe their impact on application performance.
- When finished, stop the emulation and save your test configuration for future use if desired.
Final Thoughts
Networks are complex and hard to manage. Companies need efficient network emulation tools to simulate network latency and identify bottlenecks before they cause real problems.
Netropy network latency simulator is quick to install, intuitive to configure, and easy to operate. In fact, non-technical personnel can get tests up and running in no time. The GUI provides the responsiveness of an application with the convenience of a standard web browser.
The tests deliver unsurpassed precision, enabling you to examine the impact of different network conditions, like jitter and packet loss. You can then take the accurate and predictable performance information and better understand how your applications function on your enterprise network. Want to learn more? Download the datasheet to discover how Netropy can boost your application performance testing workflows.
