How to Choose the Best CDN Provider (Complete Guide)

What is CDN?

CDN is the abbreviation of content distribution network or content delivery network. It is a worldwide circulated set-up of proxy servers employed in numerous data centers. The target of a CDN is to provide content to end-users with high accessibility, high functioning and fast speed. CDNs supply a large proportion of the Internet content today.

The content served by CDNs include the following:

• The web objects like text, scripts, and graphics
• downloadable objects like media files, documents, and software
• applications like e-commerce and portals
• on-screen streaming broadcasting
• on-demand streaming broadcasting
• Public networks

Content suppliers like media corporations and e-commerce sellers pay CDN hosting companies to provide their content to their end-users.

A CDN, in turn, pays ISPs, network operators, and carriers. This payment is for accommodating its servers in their data centers. In addition to improved performance and accessibility, CDNs also unburden the traffic served straight from the content provider's source infrastructure. This results in the possible saving of cost for the content provider.

Moreover, CDNs deliver the content provider a level of defense from DDoS (Denial-of-service attack) attacks by employing their massive spread server infrastructure to engross the attack traffic. Most of the early CDNs provided content using devoted servers operated and owned by the CDN.

However, there is a modern trend to use a fusion model that employs P2P technology. In the fusion model, content is delivered using dedicated servers as well as other user-owned computers as appropriate.

How does CDN operate?

Most CDNs are driven as an ASP (Application service provider) on the Internet. An ascending number of Internet network holders have made their CDNs to make the on-net delivery of content better and efficient. This also helps them to decrease demand on their personal broadcastings infrastructure and to make profits from content customers.

This might comprise of offering to internet service customers, the approach to media streaming. Some bigger software marquees like Microsoft construct their CDNs by their products.

Some of this includes:

• CDN77 (UK based)
• Microsoft Azure CDN
• Amazon CloudFront
• Google Cloud CDN

In CDN, the content including the potentially numerous copies may be present on several servers.

When a customer requests a CDN hostname, DNS will link to an enhanced server, by location, cost, availability, and other features. Further, the request will be handled by the server.

Do I need a CDN?

While thinking of choosing a reliable CDN, one question always arises in the customer's mind - Why do I need the CDN? 

Some of the most important reasons are as follows:

First of all, using a CDN will elevate your user's experience on speed. And, when talking about networking, speed is the most important factor!

CDN also ensures that all the users get a consistent experience.

You might host your website in a particular area; however, the majority of your website’s users will be coming from an entirely different region. For the sake of understanding, consider that you are hosting a site in North America, GTmetrix may state high speeds by your default test locality. However, if a good number of your users are coming from Europe, they would not be having a fast speed that you experience.

A worldwide CDN would allow customers from Europe to transfer static content from a nearby source. The users would not have to span the Atlantic Ocean to access the data; instead, they can make a connection to a server in London to retrieve the same data. This decreases latency and offers a quicker loading of your website.

It’s not just increased speed which CDN ensures to deliver to the users, but, they also assist in avoiding site crashes in case of traffic surges.

CDNs also assist to distributing bandwidth among various servers, instead of permitting a single server to control all traffic.

Common queries about CDN

Before choosing a CDN service, users often come across a number of questions regarding CDN. A few of them are mentioned below with their possible, satisfying answers.

1. What kind performance problem does a CDN solve?

CDN can solve a bunch of the problems, related to your networking and website. Some of them are as follows:

• Subsidiary issues such as making the global availability better
• Help in reducing bandwidth
• The biggest problem they tackle is latency which is defined as the amount of time taken by the host server to receive, develop, and deliver the content on demand for a page resource. The resources might include CSS files or images etc. Latency depends mostly on the distance of the user from the server, and it’s increased by the number of resources contained by a web page.

For better understanding, let's consider that all your resources are accommodated in San Francisco, and a user is paying a visit to your page in London.

In this case, every request has to cover a long distance from London to San Francisco and then back to London again. If there are up to 100 pages on your web page, then your user’s browser will have to send 100 discrete requests to your server with the purpose to retrieve those objects.

Classically, the range of latency is 75-140ms. However, the range can be considerably higher, especially for mobile users who are accessing a site using a 3G network. This can undoubtedly increase 2 to 3 seconds of load time, which is a thing to be considered when you realize that this is just one factor among many negatively affecting the speed of your pages.

2. Is CDN helpful in every situation?

A CDN is compulsory for many sites but is not a binding for every site. For example, if you’re a local host and are having primary local users, a CDN would not be of much help to you.

Some site owners believe that CDN alone is the solution to all of their problems. A CDN is not an individual performance solution. You should always keep in mind the fact that in the SaaS and e-commerce worlds, two of the most usual performance troubles are third-party material and server-side processing. These are the issues your CDN can’t help with.

3. Are all CDNs created equal?

Choice matters everywhere. Your choice of CDNs is very important. The advantages will differ depending on your choice of provider, along with other things including the following factors:

• how your CDN collects and keeps the content
• what is the minimum distance of users from the PoPs (points of presence)

To choose the most efficient CDN for your site, first get complete information about the location of your users.

In addition to the other factors, latency can also differ hugely between different providers.

4. Is there any variation in CDN performance, even with the same CDN?

You should keep in mind the fact that performance of CDN fluctuates a lot more than predicted Aaron held a great session in which they emphasized on how to measure CDN performance. You should preferably check out this too, for complete guidance.

5. Being a mobile user, is CDN a valid option?

Well, if you are a mobile user and are wondering whether CDN is a useful option for you or not, then there is good news. Yes, CDNs are to some extent workable for mobile users. However, it may be difficult to rationalize the price based on the minimal return.

6. Does CDN usage guarantee full availability for my site?

Every CDN provider you will encounter will ensure nearly 100% availability, even if there are huge power outages, network problems, and hardware issues. The root for this guarantee is the reality that CDNs have programmed mechanisms that detect server availability, with rapid user redirection in case a server goes down.

Well, what is meant by “nearly 100% availability”? A CDN’s uptime assurance should be defined in its customer SLA (Service level agreement). According to my opinion, if you’re interested in a particular provider, you should search for the CDN’s outage accessibility and observe what kind of information comes up.

Go to Google and conduct a search like - thenameofyourcdnprovider outage - and look for blogs on the first 2-3 pages that could have info for recent outages.

7. Do most leading sites use CDN?

The answer to this question is no! According to our latest surveys of prominent e-commerce sites, 55% of the leading 2,000 e-commerce websites in the US and 49% of the top 400 e-commerce sites in the EU don’t employ a recognized CDN.

Also, among the top 10k sites in the world, only around 49% use CDN. Here is a link with the data from BuiltWith.

Price is probably the most restrictive factor for many site owners. However, in the past few years more smart-priced options have been introduced in the market.

8. Comparison between front-end optimization and CDNs for delivering faster pages?

To get the highest speed, most of our users employ a fusion of front-end optimization, application delivery controller, content delivery network, and in-house engineering.

As I have already discussed, CDNs address the issue of speed by bringing resources near to users. This shortens the server round trips and hence makes loading of pages faster. FEO (Front End Optimization) controls performance at the front end and makes the pages render more efficiently in the browser. More practical tips on how to optimize your site speed you can read here.

9. How viable is the CDN market at present?

Another important query regarding CDN is about its cost and affordability. Many users avoid it thinking that they would be unable to pay such high price.

A few years ago, content delivery solutions had such a high cost that only a few could afford. A few could imagine paying monthly CDN bills worth hundreds of thousands of dollars. However, things have changed a lot now.

Now, there's an increasing range of competitive products, and you have to select the best and the one which suits you. The products are backed by pioneer companies which offer modern technology that works well with other technologies like real user monitoring (RUM).

Things to consider when choosing a CDN

While selecting a CDN, you should consider many factors to make sure that you get the most efficient and reliable CDN. Among a list of those features, a few most important ones are as follows:

1. Analytics

Among the best ways to determine the power of your, CDN is to measure its response time and throughput. The features you will look for in the CDN are:

• a strong analytics platform
• a system which is complete with multiple reports developed
• the capability for you to divide data in a business-meaningful way

CDNs offer some reports. Some of the reports include:

• Complete bandwidth, GB moved
• Total quantity of requests
• Usual end-user transfer cost
• Cache hit/miss fraction
• Completion fraction
• Completion fraction percentage
• Complete delivery by data center
• Complete requests by data center
• Leading hosts
• Rate of hits
• Bandwidth of approximately 95/5 Mbps
• Transfer miss fraction
• Request miss fraction
• Origin transmission
• Origin request rate (RPS)
• End–user transmission

2. Traffic Analyzer

An extremely helpful and relevant reporting application is the Traffic Analyzer. Some thorough charts are added to assist you to analyze various aspects of the delivery. Moreover, filters can also be applied to make comparisons by region, timeframe and traffic segments.

Charts contain the basic statistics of bandwidth, requests, completion ratio, end-user transfer, total GB delivered, and usual response amount for your HTTP traffic.

You should also look if there is any flexibility in the following:

• Choosing other listed charts
• Filter for any period required up to 24 months back
• Filter built on your main account, smaller and additional accounts, hosts, and areas of delivery

3. Importance of Testing

While looking for an efficient CDN, various factors are on trial. Two of the most significant factors are throughput and response time.

Response time is regarded as the time taken by a server to answer to a browser demand.

A slow response time means that there will be the slow loading of pages. This will automatically lead to unsatisfied customers no matter how optimized your pages are. Hence it can be quickly concluded that speed matters most!

Throughput is defined as the rate of effective message delivery over a contact channel.

To make the concept further clear, throughput is the measure of the strength and consistency of the connection and its effective maintenance during the session.

In addition to these factors, many other variables should also be considered while testing a CDN. However, the most significant thing is a test! Make sure that you pass the CDN through various tests and choose the one which passes all the tests. This tells that the particular CDN suits best to your needs. All the good companies give a free trial.

4. APIs

API is another important factor in the assessment of CDN. APIs provide CDN users more elasticity, upgraded security, and improved features.

APIs with leveraging capability can assist with account administration and with making user profiles, analytics, hosts, configurations, origins, etc.

Broadcasting operations can be incorporated into your dashboards, workflows, and automated processes.

5. Pricing of CDN

Well, before making any decision, the price is the first and foremost consideration undertaken by many CDN potential customers. When you are bringing a lot of bits and bytes, the prices can accumulate. When you get those price tags, make sure that you are just paying for what you need and nothing extra.

A CDN should work personally with you to appreciate the volume of traffic you’ll bring on day one.

CDN should also be able to recognize what you might produce down the road. It’s important to note that along with the actual price, you completely understand the various pricing models and the price for supplementary services.

6. Customer Recommendations

Last but not the least, complete your homework. Have a detailed discussion your colleagues, friends, and other people who are presently implementing CDN services.

Get their feedback about performance and the best of the services.

Also, ask if the company needs any improvements i.e. look for any flaws and most significantly read the testimonials.

Top CDN service providers:

• CDN77 (UK based)
  CDN77 is a UK-based provider offering 24/7 live support and Pay As You Go payment method besides their monthly plans. Known as tech innovators - they were the first CDN to support Brotli compression algorithm, HTTP/2 protocol and Let’s Encrypt SSL certificate. You can test their service with a 14-day free trial which doesn’t require any credit card.
• StackPath
• CDN.net
• Rackspace
• Cloudflare
• Amazon Cloudfront
• Google Cloud Platform

If you read this article thoroughly, I'm sure that it will help you a lot to choose the best CDN service. Good luck!