Application-layer framing

Application-layer framing or application-level framing (ALF) is a method of allowing  an application to use its semantics for the design of its network protocols.

This procedure was first proposed by D. D. Clark and David L. Tennenhouse. It works as follows:

This procedure simplifies the quality of service negotiation and provides a simpler method of error checking.
 * The application splits the data into useful segments.
 * These segments are called ADUs (application data units).
 * The ADUs can be processed in any order.
 * The lower layers keep the ADU borders.

The Real-time Transport Protocol (RTP) is an example of where the semantics of the real-time application are used to segment the data.