Mobile CDN - Speeding up Content Delivery on All Devices

By Brian Jackson
Updated on June 6, 2017
Mobile CDN - Speeding up Content Delivery on All Devices

When it comes to web performance, people are always discussing different optimizations in which you can speed up your website. One aspect unfortunately though that is quite frequently overlooked is how mobile devices come into this equation. In today's post we want to show you why it is important to utilize, what we call a mobile CDN, and how it can help ensure fast load times across all devices, whether they be desktops, laptops, or mobile phones. Mobile is changing the way we need to think about the web.

Importance of mobile on the web

According to Similar Web's State of Mobile Web US 2015 report, roughly 56 percent of consumer traffic to the leading US websites is now from mobile devices. A lot of businesses sometimes don't realize just how much mobile traffic they might be getting. While this can vary quite a bit in different categories, it is always important to check yourself in analytics. If over half of your traffic is from mobile devices, that might mean you need a whole different mindset when testing your site. In that scenario, you might even want to spend more time optimizing mobile than you do desktop.

We decided to pool three random websites ourselves, all in different categories and or markets, to see just how much web traffic was coming from mobile devices verses desktop. You can easily do this in Google Analytics by digging into the "Mobile Overview" under Audiences.

Website 1: 84% desktop traffic and 16% mobile/tablet traffic

Website Category: Marketing/Advertising

Website 2: 19% desktop traffic and 81% mobile/tablet traffic

Website Category: Ecommerce/Food

Website 3: 91% desktop traffic and 9% mobile/tablet traffic

Website Category: Web Development

As you can the results vary quite a big based on the category and audience. Some were desktop heavy, while another was mobile heavy. The ecommerce/food website we looked at had over 81% of its traffic from mobile devices. This means everything done on that website should really be mobile first, then desktop.

And if we take a look at the amount of data being used by mobile devices it has skyrocketed in the past few years, and isn't slowing down anytime soon. A big reason for this is due to third party advertising networks. According to a New York Times case study, more than half of the data used on mobile devices over news sites come from ads. These are scary figures!

According to Cisco, traffic from wireless and mobile devices will account for two-thirds of total IP traffic by 2020. By 2020, wired devices will account for 34 percent of IP traffic, and Wi-Fi and mobile devices will account for 66 percent of IP traffic. Below is a look at mobile data traffic, measured by Ericsson over the past couple years. Over the past 5 years, cumulative mobile data-traffic growth was just under 1,600%!

Pat Meenan, Engineer at Google and Daniel An, Mobile Web at Google, recently published a great article called Why Marketers Should Care About Mobile Page Speed. In goes into detail about how current mobile sites lag behind desktop sites in key engagement metrics such as average time on site, pages per visit, and bounce rate. While this is not really news to most of us, the actual stats are higher than you might think. The average U.S. retail mobile site loaded in 6.7 seconds in July 2016, but, according to the most recent data, 40% of consumers will leave a page that takes longer than three seconds to load.

In the article they discuss some of the major factors mobile sites seeing these long load times and lower conversation rates, which include:

  1. The number of page elements
  2. The number of images
  3. DOM ready times and full-page load times

These are all crucial issues that should be addressed and or fixed on your origin server, and we have discussed most of them in our past blog posts on website optimizations, image optimization, and what is blocking the DOM? Mobile devices require things to be optimized even more than desktop. However, they also didn't mention how by simply implementing a mobile CDN, that you can drastically decrease these load times. It is important to note though that a CDN isn't a magic fix. You still should always optimize your website as best you can, and then a CDN will handle speeding up your optimized content.

Mobile CDN

Globally, the relative share of 3G and 3.5G-capable devices and connections will surpass 2G-capable devices and connections by 2017. The other significant crossover will occur in 2020, when 4G will surpass all other types of connection share. The bad news is that there are still millions of devices running on 2G and 3G devices around the globe. This means you still need to optimize and figure out ways to decrease load times! And one easy way to do that is with a CDN by putting your mobile content closer to your visitors to decrease latency.

If you aren't familiar with CDNs, make sure to read our in-depth post on how CDN works. They can also benefit you in additional ways, as it pertains to mobile, such as:

  • Use of Gzip compression to control mobile data traffic
  • Use of video pacing to control excessive progressive downloading of media content
  • Use of TCP acceleration to adjust with the network environment of the mobile user

50% of your 1-second page load time budget on mobile is taken up by network latency overhead.


We wanted to show you the difference in latency times with and without a CDN implemented. This is simply from a connectivity perspective. In this test we are again using our test site (hosted in Dallas, TX) and KeyCDN's ping test tool which conveniently allows us to simultaneously test from the following 10 locations:

And here are the results between the two.

Server (POP) locationNo CDN RTT (ms)KeyCDN RTT (ms)Difference
New York, US36.90818.096- 50.97%
Dallas, US (origin server)0.7511.13851.53%
San Francisco, US39.64518.900- 52.33%
Frankfurt, DE123.0723.734- 96.97%
London, UK127.5554.548- 96.43%
Paris, FR112.4170.689- 98.5%
Amsterdam, NL118.41810.364- 91.25%
Singapore, SG202.6822.002- 99.01%
Sydney, AU191.8480.705- 99.63%
Tokyo, JP130.8043.379- 97.42%

The latency between our origin server (without a CDN) and our POPs (with a CDN) on average is decreased by 83%! You can also run your own speed test comparison. Both WebPageTest and Chrome DevTools have great methods for throttling your internet speed and emulating a mobile device at 2G, 3G, LTE, etc. You can also add custom networking throttling profiles. This can be beneficial if you are wanting to test more accurately at a specific speed.


As you can see, adapting for mobile on the web is very important. The number of people using different types of devices is continuing to expand exponentially at a rapid pace. We first recommend optimizing your site for mobile as much as possible and then taking advantage of a mobile CDN to get the content closer to your visitors, and decrease the latency involved.

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