RFC 2736 (rfc2736) - Page 1 of 10


Guidelines for Writers of RTP Payload Format Specifications



Alternative Format: Original Text Document



Network Working Group                                            M. Handley
Request for Comments: 2736                                            ACIRI
BCP: 36                                                          C. Perkins
Category: Best Current Practice                                         UCL
                                                              December 1999


      Guidelines for Writers of RTP Payload Format Specifications

Status of this Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

Abstract

   This document provides general guidelines aimed at assisting the
   authors of RTP Payload Format specifications in deciding on good
   formats.  These guidelines attempt to capture some of the experience
   gained with RTP as it evolved during its development.

1.  Introduction

   This document provides general guidelines aimed at assisting the
   authors of RTP [9] Payload Format specifications in deciding on good
   formats.  These guidelines attempt to capture some of the experience
   gained with RTP as it evolved during its development.

   The principles outlined in this document are applicable to almost all
   data types, but are framed in examples of audio and video codecs for
   clarity.

2.  Background

   RTP was designed around the concept of Application Level Framing
   (ALF), first described by Clark and Tennenhouse [2]. The key argument
   underlying ALF is that there are many different ways an application
   might be able to cope with misordered or lost packets.  These range
   from ignoring the loss, to re-sending the missing data (either from a
   buffer or by regenerating it), and to sending new data which
   supersedes the missing data.  The application only has this choice if
   the transport protocol is dealing with data in "Application Data
   Units" (ADUs). An ADU contains data that can be processed out-of-



Handley & Perkins        Best Current Practice