DNS over HTTPS: How does it impact user quality of experience?

To help improve user privacy, last October the IETF formally adopted DoH, or DNS over HTTPS. But how will DoH impact the user experience? Since measuring internet quality is our business, NetForecast has decided to investigate these concerns regarding DNS over HTTPS.

Based on our initial findings, performance concerns may be valid. We found that the estimated impact of DoH on the user experience could be significant, showing slower response times – especially for applications that require many site name resolutions. Typically, this would be news feeds, social media, and online shopping experiences.

For our test, we looked at round trip times for accessing and navigating each of the following popular websites:

  • NetForecast
  • Google
  • YouTube
  • Facebook
  • Wikipedia
  • Reddit
  • Amazon
  • Yahoo
  • Instagram

Over the course of a week, over 175,000 measurements were taken from three test servers located across different regions of the U.S. The primary result shows that DoH lookup times are much higher than DNS times. In fact, the difference was larger than expected. For the entire test cycle, the average DNS resolution time for the websites listed above was 15.1 milliseconds, compared to the average DoH lookup time of 92.2 milliseconds. That makes DoH over six times slower than DNS, which could create frustration among users.

Adding fuel to the fire, if there are any existing local latency issues in the network, this will exaggerate the effect of DoH resolution times even further. That’s why general network measurements – like those deployed by NetForecast – are a useful tool in detecting issues affecting customer quality of experience in real time. As new technologies and architectures are deployed, ISPs need a way to safeguard their business and detect when problems arise. When providing Internet service in the ‘black box’ environment of DoH, where user experience hinges on 3rd party providers, it becomes especially important.

Regardless of where you stand on the DoH debate, it’s important for Internet service providers to get ready. It’s time for them to consider how this new architecture will impact their business, since they will likely be the ones left managing customer expectations- and the angry phone calls.

To read the full results, download our new whitepaper: “Measuring DNS over HTTPS Effects on Customer Quality of Experience.”

For more information, visit www.netforecast.com.