Common Media Client Data
An end user's media player understands playback behavior better than a content delivery network (CDN) can from its limited server-side data. So, we offer support for Common Media Client Data (CMCD). This is an open specification created by the Consumer Technology Association. A media player can use it to send its expanded playback information to Akamai (and other CDNs) for storage in logs. These logs can help with troubleshooting. More data = more help fixing problems. Akamai customer support can quickly access this log data to help reduce troubleshooting time.
1 - Send CMCD data from the client
You'll want to set up your media player to send CMCD data from a requesting client. Data can be sent to Akamai using either of these methods:
- As a custom HTTP request header.
- As an HTTP query argument.
Guidelines are laid out in the CMCD specification. Look to it for the latest recommendations on transmitting information in your requests.
A single request shouldn't include both CMCD headers and query arguments. If one does, Akamai ignores the query argument.
CORS-restricted clients and CMCD data
A CORS-restricted client (such as a web application running inside a browser) has to make a preflight OPTIONS request against a CDN before it can request an object that includes custom CMCD headers. So, the HTTP query argument method is recommended for browser clients, while the custom HTTP request header method is recommended for all other clients.
2 - Set up your AMD property
Make sure your property is set up to receive CMCD data, based on how the client is sending it.
Use custom HTTP request headers
You can incorporate support for CMCD headers in multiple ways.
Create a new Akamai property
If this is a new property, support for CMCD is automatically added to the Default CORS Policy Rule. The
Create a new version of an existing Akamai property
If the property contains the Modify Outgoing Response Header behavior, either standalone or as part of the Default CORS Policy Rule, Akamai will automatically add the
Add a separate instance of Modify Outgoing Response Header behavior
If you're not employing the Default CORS Policy rule, you can include the Modify Outgoing Response Header behavior in another rule. If this is the case, this behavior's settings need to be set as follows:
Use query arguments
If you’d prefer to use query arguments, you need to do a couple of things.
Set the Cache Key Query Parameters behavior
You need to be sure that CMCD query arguments are not cached. CMCD data changes with each request. Caching these arguments will increase the load on your origin server and affect performance. Make sure that the Cache Key Query Parameters behavior in your delivery property is set up using either of these methods:
Avoid CMCD headers
Ensure that requests from the player don't include CMCD headers, as they'll take precedence.
Updated 4 days ago