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CDNs (Content Delivery Networks) are becoming increasingly popular. The obvious benefit is that they can help websites to give end users a speedier web surfing experience, but there is also another very positive side effect for the entire Internet, and it will become more noticeable the more common CDNs become.

The positive side effect is this: More CDN usage means less load on the Internet backbone.

Why? It all comes down to how most CDNs work.

Accessing a website that has no CDN

A regular website, with no CDN, serves all of its content from one static location, no matter where the website visitor is coming from. So, for example, if a European web surfer is visiting a website hosted in the United States, all the website content will be transferred from the American web hosting company across the Atlantic to the European user, via multiple network hops in both the United States and Europe.

Now contrast this with a good CDN, which will have multiple locations spread out over the world. It will make sure that content is always served from the location that is closest to the web surfer.

Accessing a website that has a CDN

When for example the European web surfer we mentioned above accesses the same site, which now uses a CDN, he will download the website content from a location in Europe, perhaps even in his own country. The data will only have to travel a fraction of the distance, with fewer network hops.

In other words: A much smaller part of the Internet infrastructure will have to be involved in the user’s interaction with this specific website.


Above: This is a visualization of the example mentioned in this article. Note that a much smaller part of the network infrastructure is used when the CDN is involved.

There may still be some data that needs to be transferred over the entire distance. Many sites only use CDNs for static files (for example images), but it will still greatly ease the load on the Internet backbone.

We suspect that 10 years from now, most web hosting solutions will have some form of built-in CDN, and this will be a Good Thing for the Internet.

What do you think?

Further reading: If you’re interested in some additional insights about CDNs, you might like to check out an article from 2008: A look at Content Delivery Networks, or “how to serve lots of content really fast”

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9 Comments

A cool little article. What do you guys recommend for a CDN? I know of Amazon S3 but is there some smaller website which is better that not many people have heard of? At the moment it seems to be massive CDN for big companies and Amazon for the rest of us.

The Rackspace Cloud Hosting suite already provides CDN “built-in”. Using Cloud Files anyone can use our CDN partnership with Limelight to serve their content via CDN. You can learn more here: http://www.mosso.com/cloudfiles.jsp.

An you don’t need to be a programmer to use it.

I’ve have been using a CDN for a couple of months and when i started to use a CDN i suddenly got more visitors from Google!?

I’m aware of Akamai (the most well know/largest), Amazon S3, Limelight/Mosso Files, Internap CDN (as resold by Softlayer), BitGravity, LocalMirror, ValueCDN, CacheFly and Nirvanix.

I do wish the CDN providers would give more details of where their locations are and example pricing.

The cheapest for storing 10Gb of files and transferring 1,000Gb per month is Amazon (at $172), followed by Softlayer (at $180), but once you start getting more requests (or you have lots of little files), Amazon’s costs start going high (due to the fact they charge per request along with data transfer and storage).

@Jonas: Really? That sounds interesting. You don’t happen to have any stats you might be willing to share…? (Regarding getting more traffic from Google.)

@Mac Tips: We usually don’t recommend any specific vendors, but Richy C probably answered your question to some extent. (Though the Amazon CDN is called Cloudfront, isn’t it? Though it integrates with S3.)

Good post to explain in the most simple terms of what features a CDN has to offer. CDN is getting cheaper for those looking for bargains and let’s the “little guys” get in on the benefits of CDN technology as well.

Another primary reason to go with a CDN is video streaming – whether that be static or live. Pusing your video through a true media server protects your content, speeds delivery and saves bandwidth.

Randy Cooper
Founder, CDN Evangelist
Find out more on CDN from the blog where the CDN pros go!
CDN Evangelist – http://www.cdnevangelist.com

CDN is a great benefit for serving specific type of contents which need low ping travel times or dont get updated to much. Its completely useless for dynamic content that changes frecuently. Internet has moved from static to live content over the past years and this where CDN doesnt work, it would create exactly the opposite effect, overloading the network. Its great for streaming but not for on the fly content. I would ratter bet that in 10 years the CDN will be package based, not content or file based like it is now.. It will be based on the network layer where the same bit packages are just recreated from a shorter hub instead of being transfered over the whole planet. This kind of CDN which im investigating would replicate the data on the network level and the client would see the exact copy without the need to upload the data to the CDN hubs. The CDN would just replicate the data from a shorter path to each visitor. Currently CDN is just like having duplicated content on several parts. This can also be made by having our own servers on different datacenters and using a live replication technology with virtualization.

No news is good news for the Super Bowl website

The New England Patriots held what seemed to be a commanding lead (17-15) with five minutes left of Super Bowl XLVI last night. But the New York Giants came back and managed to win with 21-17.

As exciting as the game sounds, we missed the whole thing, instead spending our time watching the Superbowl.com website.

It turned out to be a rather dull thing to do because the site held up well and there was no downtime at all. The response time also didn’t give away anything significant in terms of online Super Bowl traffic.

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As Super Bowl 46 is approaching, fans will flock to the Lucas Oil Stadium in Indianapolis, Indiana, and to TV sets around the world to follow the New York Giants battle it out with the New England Patriots.

Kickoff is scheduled for 6:30EST on Sunday, February 5, and we’re already monitoring Superbowl.com to see how the site will handle the event.

What team will win Super Bowl 46? How will the site cope? We can only wait to find out.

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Weekend must-read articles #2

Every Friday we bring you a collection of links to places on the web that we find particularly newsworthy, interesting, entertaining, and topical. We try to focus on some particular area or topic each week, but in general we will cover Internet, web development, networking, performance, and other geeky topics.h

This week we bring you a collection of articles focusing on cloud, with a few other topics thrown in to boot.

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Out of the 59 US-based e-commerce sites we monitored during the holiday season last year 28 scored a perfect 100% uptime for December.

Whether this helped spur on the booming sales in the US, we don’t know, but retail e-commerce spending in the US reached $37.2 billion for the November to December 2011 period. That was an increase of 15% from the same period in 2010.

We decided to dig into the numbers for these e-commerce sites to see how well they did in terms of uptime and performance. After massaging the data coming from our Pingdom probes, it turns out that the sites overall performed well during December 2011 in terms of uptime, but response time was an issue for several sites.

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Pingdom Podcast #5

Pingdom’s Mobile Podcast is a weekly show about Internet, web, and mobile stuff.

In this show, Saleh also gives us an update on the pending submission of his Carbon for Windows Phone Twitter client. We’re also joined by Mario Lurig, who talks about using Amazon S3 and Cloudfront to speed up a website.

Read more