Content Delivery Network - What You Really Need To Know

What is a Content Delivery Network CDN?

Using a Content Delivery Network (CDN) hosting instead of a standard hosting means that you will load some of the traffic to cloud based servers in data centers strategically located in different regions of the world. The servers from a data center closer to the end user will always be triggered, so the content reaches him faster.

CDNs are basically surrogate web servers distributed across different data centers in different geographical regions to deliver content to end-users, based on proximity of this user. They help global availability of a website, address the latency problems and gain size, i.e. reduce bandwidth.

What Kind of Problems CDN Solve?Implementing a CDN affects everything, from your internal architecture to the cost of your IT staff, performance management and more. True power of a content delivery network is yet to be revealed in future decades, as it soars by 20% each year, but so far, the major advantages of using one are:

• significantly reduced page load time of your website• increased revenue by 1% for every 100 ms of improvement to your page

load time• retaining more customers (they are more satisfied)• more manageable traffic• maximum availability of your product• more secure network• no geographical barriers• easy delivery of video, audio rich content

• build more interactive website at no cost of losing visitors due to latencies

• reaching mobile customers with ease• branching out to new markets, regions• easy management of traffic peaks• more scalability to your business, you can grow it as much as you want

to• less or now downtimes• setting your own criteria to enable the best possible performance for

your website

• build more interactive website at no cost of losing visitors due to latencies

• reaching mobile customers with ease• branching out to new markets, regions• easy management of traffic peaks• more scalability to your business, you can grow it as much as you want

to• less or now downtimes• setting your own criteria to enable the best possible performance for

your website

How can I implement CDN?

More than 90% of business owners now realize the benefits of using the cloud, the reliability of the cloud and cloud investments keep them on top of the market and safe against competitors.

Implementing a CDN to the cloud gives them even more market opportunities, helps them scale their business as much as they need to, and pushes them to keep up with technological revolutions.

There are no general rules to how to implement CDNs since each type of CDN has its own configuration process. What is important is that YSlow recognizes the CDN and for blogs you may even use plug-ins.

How much does a CDN cost?The usage of Content Delivery Networks (CDNs) is rapidly growing in the era of mobile and app-based internet. The effort to simplify navigation and improve user experience is taken both by vendors and network operators.

The speed of a website affects everything, from infrastructure to cost of an e-commerce. With CDNs, the data is served to the end-user from the surrogate server located nearest to him.

A CDN replicates content from the origin server to cache servers, scattered over the globe. Renting such service from a CDN provider has proved to be much simpler and more cost effective than maintaining an on-premise server of your own.

Also, the content that the vendors provide is seeking to be highly interactive, and the varying round-trip of the content/data needs to be optimized, the latency minimized.

Of course, the value measured will depend on the type of the service provided, on whether you are a vendor/content owner, or a CDN service provider. For the content owners, basically two questions need to be answered to find where the value of their CDN implementation lies:

• how does it improve overall retail service delivery?• how does it support their efforts to win/retain customers?

There are many different stakeholders in the CDN market, like content providers, content makers, data centre providers, Internet Service providers (ISPs), Internet access providers, Internet backbone providers, CDN providers, advertisers, and so forth.

As the market dynamics continue to evolve, so will evolve the profiles, the merging trends, and price strategies of different stakeholders.

What is POP?POPs (also, points of presence, edge caches) are distributed servers where static resources are stashed across a region or worldwide, thereby bringing resources closer to users and reducing round trip time.

Is there anything else I can do to speed up my website?The options to make your website faster, split in two major categories:

• speeding up your browser side technologies (browser caching, minifying page elements, minimizing redirects)

• speeding up by using some of the acceleration technologies (Content Delivery Networks, dynamic CDN, media streaming)

Browser-side optimization

Use the optimal formatting for images: JPEG’s are for photographs, GIF’s are for low color images/flat color images, and PNG’s are for everything else. Also, try and adjust the image size yourself, i.e. set the width and height (width=’60px’ height=’30px’). Use web tools for image optimization (such as Riot, ImageOptim). Don’t store everything locally, try using services like Flickr.

Minify the code for CSS and JavaScript. Again, there are some tools available such as Code Minifier, Minify, JSCompress, CSSCompressor… Put CSS in separate .css files, not embedded in each page. Put Java Script files in .js files, or if you need to include them in HTML, put them at the bottom of the HTML page.

Browser-side optimization #2Reduce the number of components of your page. Make a simple design. This will immediately reduce the number of HTTP requests to download all the graphics, video and JavaScript files from your website. Also, avoid Flash elements, or use as little as possible. Try to host as much elements as possible on other websites.

Minimize redirects. Each redirect creates an additional HTTP request and adds RTT (round-trip-time) latency. Use redirects only when absolutely necessary. The more redirection you have, the slower the end user will get to the desired page.

Server-side optimizationReduce DNS Lookups. It takes some milliseconds for DNS (Domain Name System) to resolve an IP address for a given hostname or domain name. The browser cannot do anything until the process is fully completed. Ideally, you should use no more than 4 hostnames. This will also allow for a higher degree of parallel downloads.

Set up a GZIP compression on your web server. It saves bandwidth and solves problems with older browsers. The compressing options vary depending on the server.

Server-side optimization #2Employ media streaming methods. Real-time protocols will read compressed files to deliver data as it arrives. And dismiss the data once it has been streamed. The option to stream media will allow faster views, and compression/decompression methods will dispose of all the unnecessary data that would otherwise clog your connection.

Don’t forget to run a website speed test first. In this way, you will know more precisely which components need to be targeted first. There are many tools that can detect the root cause of your website being not fast enough, such as YSlow, Pingdom, WebPageTest, Cuzillion, Wireshark, HTTP Archive, PageSpeed and so on.

Is CDN useful for every site?The first rule of e-commerce says that if the customer cannot find your product/service, he cannot buy it. The number of web shoppers in US alone in 2011 was said to be 178,5 million and is to reach 200 million by 2015 (source: eMarketer) which will equal 90% of all internet users in US.

Now, to consider the patience of your customers. 1 out of 4 customers is sure to abandon a webpage that takes more than 4 seconds to load.

So, yes, improving performance is absolutely a must for every website except if the content is hosted locally and their users are local, in that case CDN doesn’t make that big of a difference.

What Can I Expect as a Result of Using a CDN?Faster websites result in better user experience, better search engine rankings and more conversions. 1 out of 4 visitors won’t wait for the page to load for more than 4 seconds. The ideal is to find balance between neat performance and indulging the end users’ desire for interactivity, delivering script intensive content.

CDNs help with major performance problems on the server-side, mainly latency, availability and bandwidth.

How Should I Select My CDN Vendor?As CDN performance primarily depends on geographical location and the proximity of POPs to end-users, you should locate your users first. Also, you should know who your regular user is, define the type of content you are delivering, your business model and what specific requirements you need in order to become more successful.

Knowledge of your specific needs is crucial as performance fluctuates among CDN providers. With this information you make a request for proposal and go through the feedback the CDN or service provider gives you. It is important that you get an idea of:

• how will network performance be measured• what chances there are for outages and how will you be compensated• if the provider will charge overages• what is indeed supported in terms of delivery

What If I Don’t See Any Results?Providers of Content Delivery Networks (CDNs) vary in service. Some will perform better in China, some in US, some in Australia. Some will include one feature, but not the other. And you’ll want to be on the right cloud at the right time.

CDNs are known to provide a more secure network, reduced loading time of your page, manageable traffic, maximum availability, and so on. An irreplaceable tool that will improve the entire technological infrastructure that backs up your business. Whether you are in e-commerce business, or your website is supposed to deliver various audio, video rich content.

Using multiple CDNs is smarter than using one CDN because:

• CDN providers perform differently in different geographical regions• Not all CDN providers are reliable as others• Not all CDN providers include same features and strategies as others• You don’t need to switch CDN providers as this process becomes automated

Shouldn’t I just optimize my website?Statistics for your uptime, response time, website performance. Plus,historical records of all downtimes and errors and performing speed tests (e.g. with Pingdom) will help you decide whether you need to only improve your CSS files asset, do simple optimizing tricks, or use Content Delivery Network (CDN) hosting which uses servers located at different data centers to deliver content from the server that is closest to the end user.

Bear in mind that 250 milliseconds will make a difference between you and your competitor, nowadays.

Does CDN guarantee 100% availability?CDNs improve overall global availability of a website but the performance depends on the geographical location of a server and of a vendor, as well as the number of vendors that you are hiring. Having more than one is a surest way to avoid downtimes.

ConclusionWith global CDN market changing and bringing ever more performance technologies and solutions, it is rather complex to describe each and every potential use case. It depends on your overall business goals, strategies and competitive landscape on which performance technologies will you use. Use the comments to ask additional questions on which we’ll try to answer in future blog posts.

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