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 D. L. Tennenhouse.^[1] It works as follows:

• 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.

This procedure simplifies the quality of service negotiation and provides a simpler method of error checking.

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

References

1. Clark, D. D. and Tennenhouse, D. L. (1990). Architectural considerations for a new generation of protocols. In: ACM SIGCOMM Computer Communication Review archive Volume 20, Issue 4 (September 1990), Pages 200 - 208, ISSN 0146-4833.