2.1.1.2.3.2 Transmitters

The transmitter MUST begin the license update procedure by sending a control frame [$c], as defined here to the receiver. The control frame MUST be sent in the entity-body of the response to the GET request that the receiver sent to request data transfer. The control frame MUST contain a license response message with a leaf license.

The license response message in a control frame MUST NOT be Base64 encoded [RFC3548].

When the Framing Header mechanism is used, the license delivered as part of the license retrieval procedure MUST always be a root license. The transmitter MUST deliver a leaf license before it starts delivering the content. As a consequence, if a data transfer request succeeded, the GET response MUST be composed of the following frames:

  1. Control frame [$c] carrying a license response message with a leaf license.

  2. One or more data frames [$d].

  3. If a key or a policy (1) change during the transmission of the content requires an additional license update, then steps 1 and 2 are repeated with new data for each license update.