A Content Delivery Network (CDN) is a network of servers that delivers webpages to website visitors based on the geographic location of each visitor and the origin of the webpages. Using a CDN allows your webpage load times to be faster for global audiences — no matter where visitors are located around the world, they will consistently see page load times that are fast.
A CDN copies your webpages to a network of servers, and then sends them to geographically different locations, caching the contents of each webpage. When a visitor requests a webpage that is cached by a CDN server, the CDN redirects the request from the originating website's server to the server in the CDN that is closest to the visitor, and then delivers the cached content. The CDN will also communicate with the originating server to deliver any content that has not yet been cached.
Acquia Cloud Edge CDN is a globally load balanced CDN that you can purchase and use as an addition to your Acquia Cloud Site Factory subscription. For more information, see Using Acquia Cloud Edge. If you have any questions about using Acquia Cloud Edge CDN or a different CDN with your Acquia Cloud Site Factory websites, contact your Acquia account manager.
What does a CDN do for your website?
A Content Delivery Network accelerates the process that browsers use to load your website, making it faster and more efficient. The closer the CDN server is to the user, the faster the content delivery. CDN services are invisible to your end users, except for the superior experience your site delivers.
In addition, your website content is cached on the CDN servers, making it more accessible and ensuring availability. In the event of routine site maintenance or rare server failures, Acquia Cloud Site Factory’s CDN support will provide a read-only version of the site as long as necessary.
Content delivery without a CDN
When a visitor goes to your website, their browser requests a webpage from the server that hosts the page. This starts the following chain of events:
- The web page request is sent to the visitor's Internet service provider (ISP).
- The request then "hops," sometimes many times, to a server on its way to the web server that hosts the website.
- At some point, the web server that hosts the website receives the request and sends the page back to the browser.
- The page then "hops" to a server on its way back to the visitor's browser, sometimes many more times, until the browser receives the page.
- The browser then scans the page and prepares to display the page for the site visitor. If the page includes embedded media, such as images, videos, and advertisements, the browser must send requests for each of the media items. The more media on the page, the longer the page takes to load.
Content delivery with a CDN
To improve your page load times, the CDN anticipates the site visitor's need for media so pages load faster and more efficiently.
When the browser requests a page accelerated by the CDN:
- The web page request is sent to the visitor's ISP.
- The request then "hops" to a server on its way to the web server that hosts the website.
- The request reaches a CDN server, which then routes the request to a server close to the Acquia Cloud Site Factory server, potentially skipping several "hops."
- Acquia Cloud Site Factory receives the request and sends the page back to the browser.
- The request reaches a CDN server, which sends the page to a server close to the browser.
The CDN server scans the web page, sends requests for the page's embedded media from Acquia Cloud Site Factory, and keeps a copy of the media.
- The browser receives the page and scans the page for display.
- When the browser makes requests for embedded media, the request only goes to the CDN server that sends the copies of the media it already retrieved, potentially reducing the media retrieval time.
Enabling CDN support
To enable CDN support for your website, contact your Acquia Cloud Site Factory advisor.