Each CDN provider offers a different set of features and options. A particular feature that is available from one CDN provider may not be available from another. However, A few important core features that you want to look for in a CDN provider include the following.
A Pull Zone automatically fetches (pulls) the requested content from your origin server and caches the assets on the CDN's edge servers. In most cases, a Pull Zone is the preferred option for any content management system (CMS) such as WordPress or Typo3. If you are curious, 79% of KeyCDN customers are using pull zones.
A Push Zone requires that you upload your content to a CDN storage cloud which is then distributed to the edge servers. Most providers support FTP as well as rsync over SSH to upload your data. Push Zones are mainly used for distributing files larger than 10MB or for files that rarely change (such as documents, videos, etc).
HTTP/2 is a new network protocol with the aim to make the web faster. HTTP/2 is a feature that can extremely reduce page loading time. The 3 main benefits are:
- Allows client and server to compress request and response headers, which reduces bandwidth usage when the similar headers (e.g. X-Cache) are sent over and over again for multiple requests.
- Allows multiple requests over a single connection and therefore saving on round trips between client and server. Further, preventing low-priority assets from delaying higher-priority requests.
- Enables the server to proactively push assets to the client that it knows the client will require (e.g. CSS and images) without waiting for the client to request them.
Let’s Encrypt Integration
This feature is currently unique to KeyCDN. This means no more buying an SSL certificate if you want to use a custom zonealias.
For companies with Let’s Encrypt integration, this makes the deployment for the end user much easier. There is no more generating a CSR, saving your private key, uploading your certificate and all the back and forth emails. For most deployments, it will now be a simple one-click process.
Secure Token allows you to generate secured links with an expiration time. Once a token has expired, it is not possible anymore to access the content.
Hotlink protection refers to restricting HTTP referrers in order to prevent others from embedding your assets on other websites. Hotlink protection will save you bandwidth by prohibiting other sites from displaying your images.
Origin shield is basically an extra caching layer which reduces the load on your origin and accelerates the distribution of your content from the origin server to your edge servers. Origin Shield is a great feature to reduce the traffic on your origin server to an absolute minimum and protect your infrastructure from abuse or traffic spikes.
Gzip compresses your web pages and stylesheets (text, html, js, css or xml files) before sending them over to your browser. This allows for a much faster load time as the files are significantly reduced in size. Make sure your CDN provider supports Gzip compression.
Custom CNAME Support
By default when you setup a zone with a CDN provider your assets will point to their default Zone URL such as lorem-1.kxcdn.com. Setting up a custom CNAME allows you to point your assets to a subdomain on your own domain such as cdn.yourwebsite.com. This can be beneficial for branding as well as for SEO purposes when it comes to indexing your images.