What is Latency?

In the tech world, slow websites with a high page load time can be frustrating.

Latency is another term for a website’s load time.
Tammy Everts, an expert at Webperformancetoday.com, defines latency as “the amount of time it takes for the host server to receive and process a request for a page object. The amount of latency depends on how far away the user is from the server.”

Hearing that, you might think, “Host server? Page object?” Everts goes on to give a “real-world” definition. When you visit a website, each page you click on contains a certain amount of objects.

These objects can be things such as images, CSS files, blocks of text and more. If a page contains 100 objects, you’ll need to wait on your Internet browser to make 100 individual requests to the host server. The host server is the computer where a particular website is located and is made available to users online.

When does latency happen?

No matter how fast your Internet speed is, you’ll experience latency. That’s because latency is simply the page load time. So, the real question isn’t
<itemprop=”name”>“When does latency happen?”
Instead, it should be “When does latency negatively affect a user’s Internet experience?”

The answer depends on how many objects are included on the page the user wants to visit. Let’s go back to the webpage with 100 objects. Each object requires at least 20-30 milliseconds of latency – giving you a page load time of about 2 or 3 seconds.

Latency can happen for a variety of reasons, including:

  • Propagation – How long it takes for a packet of data to travel between one location to another. Since packets travel at the speed of light, this depends on how far away a device is from a host server.
  • Transmission – The transmission of a signal will be affected by the type of Internet service you use, such as cable, fiber optics, etc.

Many pages can contain 300-500 objects. To combat excessive latency (more than 3 seconds), websites have several options. They can try to:

  • Bring the content closer so the server round trips will be shorter
  • Reduce the number of round trips