Kentik - Network Observability
What is Synthetic Monitoring?

What is Synthetic Monitoring?

Synthetic monitoring is the active process of simulating visitor requests to a network-accessible resource and testing for availability, response time, and other performance metrics.

Increasingly, modern Network Performance Monitoring solutions are incorporating synthetic monitoring features, which are traditionally associated with a process/market called “Digital Experience Monitoring”. In contrast to flow or packet capture (which we might characterize as passive forms of monitoring), synthetic monitoring is a means of proactively tracking the performance and health of networks, applications and services.

In the networking context, synthetic monitoring means imitating different network conditions and/or simulating differing user conditions and behaviors. Synthetic monitoring achieves this by generating different types of traffic (e.g., network, DNS, HTTP, web, etc.), sending it to a specific target (e.g., IP address, server, host, web page, etc.), measuring metrics associated with that “test” and then building KPIs using those metrics.

These synthetic tests are both automatic and periodic. They are conducted at regular intervals (even down to sub-one-minute intervals in the case of synthetic monitoring solutions like Kentik Synthetics) to ensure that an application or service is still performing as expected.

Synthetic Monitoring: Types of synthetic tests
Synthetic Monitoring: Screenshot from Kentik Synthetics illustrating the wide variety of synthetic tests that might be configured.

When researching synthetic monitoring, the related topic of passive “Real User Monitoring” (RUM) is likely to turn up. Real User Monitoring involves capturing and analyzing each user transaction/interaction with an application. The idea is to track and monitor the actual usage of an application, and record what happened (after the fact). In contrast to synthetic monitoring, RUM is a form of passive monitoring.

Active vs. Passive Monitoring

It’s not a matter of which is better. It depends on what you’re trying to accomplish. Here are a couple of short definitions for both of these terms as they pertain to monitoring:

  • Active: A proactive test simulates a user by accessing a resource, waiting for a response, and interpreting any results from the communication. Synthetic monitoring is a form of active monitoring. A network management station that polls devices on a network is also an active monitor.

  • Passive: Passive monitoring reactively monitors actual/authentic user interactions with a resource then measures and interprets the communications. Real user monitoring is a form of passive monitoring. Placing a packet analyzer on the network and observing traffic is also a form of passive monitoring.

Both active and passive monitoring are useful and, while they are alternatives, combining both enables improvements and optimizations in the end-user digital experience.

The Goal of Synthetic Monitoring

On the surface, the goal of active synthetic monitoring is to ensure that an application or service (e.g., web page, DNS) is up and responding to actual end users in a timely manner. It can answer questions such as:

  • Is the DNS responding to end users in under 50 milliseconds?
  • Is the website up and loading in under 1500 milliseconds?
  • Are shopping cart transactions working?
  • Are API endpoints available and responding in the expected manner?

To accomplish this, the synthetic transaction monitor generally measures two things:

  • The availability of the resource over time (e.g., 99.999% up-time)
  • The responsiveness in milliseconds of the resource over time

This reliable routine operation can provide more details than the above implies. Trending and alerting also play significant roles in this topic. These details are below. (See also: “What is Synthetic Transaction Monitoring?” for more detail about the monitoring of specific web transactions that result from user actions in a site or web application.)

Geographic Distribution of Synthetic Tests

Connections to online resources might originate from anywhere in the world. This means we can’t monitor a cloud-hosted resource for availability and responsiveness from just a single location. Synthetic tests typically measure from multiple, geographically diverse locations, using testing agents located in different datacenters around the world.

For example, Kentik has built out a global network of synthetic testing agents that are used by customers to verify performance levels of all major public or private cloud-based applications and SaaS applications. These agents have been located inside Amazon Web Services, Google Cloud Platform, Microsoft Azure, Alibaba Cloud, IBM Clouds. Additionally, customers can easily install custom agents in their own geographically-diverse datacenters.

With numerous network and infrastructure elements that need to be tested and a user population that is geographically dispersed, the number of testing combinations and permutations can grow to be very large. As a result, the configuration of synthetic tests can become complex and time-consuming when, for example, you want to test between multiple cloud regions (such as AWS regions).

To manage this complex environment, vendors have developed tools that make implementing and monitoring synthetic tests possible on a large scale. In the following video, Kentik Synthetics expert, Anil Murty, demonstrates the easy configuation of a synthetic testing “mesh” between a variety of cloud services:

This video is a brief excerpt from “How to Continuously Monitor Inter- and Intra-Cloud Performance”—you can [watch the entire presentation here]( “On-demand webinar, “How to Continuously Monitor Inter- and Intra-Cloud Performance"").

Why Synthetic Monitoring is Important

Reputation and service level agreement validation are two big reasons why staying ahead of performance issues is a must. It’s really simple—poor connections can lead to unhappy customers and declining revenue. The sooner NetOps can detect an availability issue, the faster they can react.

Many users today see excessive application latency as a form of outage. Understanding and monitoring when a critical service drops below a minimum level of performance is paramount. A global network of agents that allow for omnidirectional synthetic transaction monitoring is one of the best ways to ensure that all users, regardless of physical location, are experiencing an acceptable level of service.

About Kentik’s Synthetic Monitoring Solution

The Kentik Network Observability Cloud offers a modern, SaaS-based approach to digital experience monitoring. Kentik delivers network performance monitoring and diagnostics that combine flow-based monitoring, cloud network observability and synthetic monitoring features to enable for proactive monitoring of all types of networks.

Start a free trial to try it yourself. Kentik’s 30-day free trial includes a generous allotment of synthetic testing credits that can be used to perform real-world testing on the applications and services important to your own organization.

Updated: September 01, 2022
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