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Configuring Dynamic Content Acceleration

Configuring Dynamic Content Acceleration

Dynamic Content Acceleration (DCA) is a technology to accelerate the dynamic web content. It provides improved reliability, offload, and network performance over your original web infrastructure, while handling the specific requirements of dynamically generated content — without a costly hardware build-out. Using real-time network optimizations and advanced caching techniques, it speeds and secures interactive websites.

Working with DCA configurations

To enable DCA, follow these steps:

  1. Open the page of a specified CDN mapping, click Settings from the navigation pane. Click Edit from the Optimization settings, then select Dynamic content acceleration from the Optimize for list menu.

  2. Enable DCA:

    • Download the route detection 'test object', or use your own test file, and upload it to your origin server. For more information about the criteria of the test object, see Detection path.

    • Type the path of the object in the Detection path field. Click Test to open a new browser window to verify that the object can be reached.

      If the window is blocked, update your browser settings to allow pop-up windows, or you can use your own method to check that the detection path is reachable.

    • Enable/Disable Prefetching and Image compression.

  3. Click Save to save the settings. If the Detection path is unreachable, the optimal route for dynamic content acceleration is impacted.

Understanding DCA concepts

Detection path

Detection path is used by Akamai Edge servers to find the best optimized route from Edge servers to origin. The best path to origin must be known at the time a user’s request arrives at an Edge server because any inline analysis or detection would defeat the purpose of speeding up things.

To accomplish this, you are asked to place a test object on your origin. Edge servers periodically fetch the test object from the origin using each of the candidate paths, including the direct path (the default path through the internet from Edge to Origin).

The fetches of the test object are called the races. When a real request comes in, the Edge consults the most recent race data to send that request over the fastest path to the origin. You can download the provided test object and upload it to the origin server, or you can use your own test object.

A valid test object must:

  • Get HTTP 200 response without authentication
  • Not contact a database or do any back-end processing
  • Be a static text file of content-type text/HTML
  • Be approximately the size of an average page, but no less than 8 KB

Detection path is designed to work only for HTTPS domain mapping (SAN HTTPS or Wildcard HTTPS).

Prefetching

Prefetching is to inspect HTML responses and prefetch embedded objects in the HTML files. Prefetch works on any page that includes <img>, <script>, or <link> tags that specify relative paths. It also works when the resource hostname matches the request domain in the HTML file, and it is part of a fully qualified URI. When it is set to On, Edge servers prefetch objects with the following file extensions: aif, aiff, au, avi, bin, bmp, cab, carb, cct, cdf, class, css, doc, dcr, dtd, exe, flv, gcf, gff, gif, grv, hdml, hqx, ico, ini, jpeg, jpg, js, mov, mp3, nc, pct, pdf, png, ppc, pws, swa, swf, txt, vbs, w32, wav, wbmp, wml, wmlc, wmls, wmlsc, xsd, and zip.

Image compression

Serving compressed images reduces the amount of content that is required to load a page. This helps offset less robust connections, such as those formed with mobile devices. If your site visitors have slow network speeds, Image Compressing technology can automatically increase compression of JPEG images to speed up loading. However, Image Compressing results in lossy compression or irreversible compression, and might affect the quality of the images on your site.

Image Compression supported file extensions: .jpg, .jpeg, .jpe, .jif, .jfif, and .jfi.

In order for the feature Image Compression to work for DCA, you must make sure that the path of the image files is cacheable. See Caching to set the images cacheable.

Caching

When DCA is enabled for your CDN mapping or origin, the Akamai Edge servers cache (or prevent caching of) contents based on your settings:

  • To enable caching of contents under the path, set Respect header to ON and set the caching headers in your origin (for example, Cache-Control:public, max-age=31536000).

  • To prevent caching of contents, do one of the following:

    • Set Respect header to ON and include headers in your origin, which prevents caching (for example, Cache-Control: no-cache, no-store).
    • Set Respect header to OFF (default), create a TTL with a path to match your contents, and set a 0 value.

In some cases, you might want to mix static (for example, images, CSS, JS) and dynamic assets under the same path, so you might need to make some assets cacheable. You can do this with the following options:

  • Set Respect header to ON and set the caching headers in your origin (for example, Cache-Control:public, max-age=31536000).
  • Set Respect header to OFF (default), create a TTL with path to match your static contents, and set the value as the wanted caching time.