Application-layer framing explained

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

See also

• Frame (networking)
• Head-of-line blocking
• Reliable byte stream

Notes and References

1. Clark, D. D. and Tennenhouse, D. L. (1990). Architectural considerations for a new generation of protocols. In: ACM SIGCOMM Computer Communication Review archiveVolume 20, Issue 4 (September 1990), Pages 200 - 208, ISSN 0146-4833.http://portal.acm.org/citation.cfm?id=99553