CDN or Content Delivery Network and How to Choose One?

A Content delivery network or CDN is a collection of global servers that caches and delivers content such as images, videos and Javascript files. Instead of one server tackling every visit, when a user requests a web page, for instance, content on that page is delivered by the closest edge server rather than the origin server.

CDN thus decreases page load time and makes your site faster.

In contrast to one server, CDN can withstand high amounts of traffic, provide inexpensive data transfer costs, and provide reliability.

When you look at the CDN options, the plethora of available choices is just overwhelming. In spite of that you would need to choose one and therefore you should be able to select one.

For choosing a CDN, you must know what to look for and more importantly what your requirements are.

Before you spell out your needs, you should have an idea what are the features that are offered across CDNs and then decide which features you require.

Features of CDN

Setup

Most of the CDNs offer instant setup. All you need to do is let your DNS point to them or add few more details. Some like Max CDN have one click setup if you are already using WP total cache. Do not chose a CDN without instant set up.

POPs

POP refers to points of presence. Though there is more technical aspect to it, let us assume that POPs represent number of servers [actually they could be proxies too]. So definitely, a CDN with greater number of  POPs should be better but there is more to functioning of CDN than number of POPs. But for sake of simplicity, let us stick to the idea that more POPs across the globe vast reach. You can also look for number of POPs in a particular region to cater your audience there.

Pricing

Should you go for a free CDN or pay for the service. If you are new and undecided, I would suggest to try Cloudflare which is free. If you wish to grow you can go premium for a small monthly payment.

If your needs are more than what free service offers or you like some other CDN which offers paid only service, compare the prices which have extreme variations. For the beginner, I would suggest “pay as you go” option, which mean that money you spend depends on the quantum of service used. Initially, desist from joining a fixed charges per month service because it could be expensive and you might not need what is being offered.

Secondly, see if the CDN provider has a transparent price policy and there are not any hidden charges on request placements.

Push or Pull

There are two different types of CDNs: push and original pull.

Some sites work best with push CDNs, and some work better with pull CDNs.

A push CDN works very much like secondary server. The user uploads content directly to the CD and links to it.

Users can specify the content that is uploaded, when it expires and when is is updated.

This method is also the most efficient in terms of how the traffic is used. Content is uploaded only when it is new or changed, thus keeping traffic to a minimum.

In case of origin pull, the site owner leaves the content on their server and rewrites their URLs to point to the CDN. When asked for a specific file, the CDN will first go to the original server, pull the file and serve it.

The CDN will then cache that file until it expires.

Pull CDNs minimizes storage space. But is s less flexible as it can create redundant  for search of file.

Instant Purge

Instant Purge lets you update stale content within 150 milliseconds or less. When you issue a purge request, servers stop delivering cached versions of that content. That means content is updated  across the servers in minimum time.

Statistics

You should be able to have real-time stats. CDNs also provide analytic services to track your usage statistics and raw logs.

Data compression

Gzip compression for data is common feature across various CDNs

Data Storage

Usually served on a per-gigabyte basis, this can be used for backup, caching, or general storage. For CDNs to be fast, they must be using Solid State Drive. If your CDN is not 100% on SSD, just forget it.

Media Delivery

This becomes important if your site is too media heavy. CDNs can provide better media experience by streaming  HD-quality video, high-quality audio, and other media.

The size of a video CDN varies, depending on the content provider, the content volume and offerings, and the number of customers served.

When subscribers access content through a CDN, they enjoy faster streaming rates and greater reliability, as well as value-added services like mobile device detection and optimization.

Origin Shield

Origin Shield is a mechanism to protect origin server from overload. Origin shield is a mid-tier caching layer which sits between the CDN and your origin to protect you from request overload.

Suppose you rest your cache or publish new content. All the CDN servers would send the request to the origin when origin shield is absent. But when enabled,  these requests are sent to Origin Shield. It then filters these multiple requests into a single origin request.

Security

SSL support, secure token [to define expiration of the document], hotlink protection [disallowing other domains from linking to your images, videos and files] and DDOS protection [protection against DDOS attacks].

Support

How is the support of CDN company you are considering. How do they support their customers. Email only or phone and email both! How is company reputed in terms of support. A good company with pathetic customer support is big no.

I hope that would answer a lot of queries in your mind about choosing a content delivery network for your WordPress blog.

Which CDN do you use? What feature you are most happy with? Please do share

What kind of support do you expect from a CDN?

It’s easy to check what kind of support is on hand, whether it be live chat or email support. Some CDNs offer technical assistance over the phone.

It’s also worth noting whether a CDN is available 24/7, and having a look through their service level agreement.

Create Your Need Profile

What are your bandwidth needs? You can find your bandwidth usage by logging in to your web host account and look at your stats.

With less traffic, you would not need a premium service. But if your traffic is to the tune of 500 GB per month, it does make sense to include CDN in your armamentarium.

 

 

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