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Session Description Protocol (SDP) Bandwidth Modifiers for RTP Control Protocol (RTCP) Bandwidth (RFC3556)

IP.com Disclosure Number: IPCOM000018628D
Original Publication Date: 2003-Jul-01
Included in the Prior Art Database: 2003-Jul-29
Document File: 9 page(s) / 15K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

S. Casner: AUTHOR

Abstract

This document defines an extension to the Session Description Protocol (SDP) to specify two additional modifiers for the bandwidth attribute. These modifiers may be used to specify the bandwidth allowed for RTP Control Protocol (RTCP) packets in a Real-time Transport Protocol (RTP) session.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 18% of the total text.

Network Working Group                                          S. Casner

Request for Comments: 3556                                 Packet Design

Category: Standards Track                                      July 2003

         Session Description Protocol (SDP) Bandwidth Modifiers

               for RTP Control Protocol (RTCP) Bandwidth

Status of this Memo

   This document specifies an Internet standards track protocol for the

   Internet community, and requests discussion and suggestions for

   improvements.  Please refer to the current edition of the "Internet

   Official Protocol Standards" (STD 1) for the standardization state

   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document defines an extension to the Session Description

   Protocol (SDP) to specify two additional modifiers for the bandwidth

   attribute.  These modifiers may be used to specify the bandwidth

   allowed for RTP Control Protocol (RTCP) packets in a Real-time

   Transport Protocol (RTP) session.

1.  Introduction

   The Real-time Transport Protocol (RTP), RFC 3550 [1], includes a

   control protocol RTCP which provides synchronization information from

   data senders and feedback information from data receivers.

   Normally, the amount of bandwidth allocated to RTCP in an RTP session

   is 5% of the session bandwidth.  For some applications, it may be

   appropriate to specify the RTCP bandwidth independently of the

   session bandwidth.  Using a separate parameter allows rate-adaptive

   applications to set an RTCP bandwidth consistent with a "typical"

   data bandwidth that is lower than the maximum bandwidth specified by

   the session bandwidth parameter.  That allows the RTCP bandwidth to

   be kept under 5% of the data bandwidth when the rate has been adapted

   downward.

   On the other hand, there may be applications that send data at very

   low rates but need to communicate extra RTCP information, such as APP

   packets.  These applications may need to specify RTCP bandwidth that

   is higher than 5% of the data bandwidth.

Casner                      Standards Track                     [Page 1]

RFC 3556       SDP Bandwidth Modifiers for RTCP Bandwidth      July 2003

   The RTP specification allows a profile to specify that the RTCP

   bandwidth may be divided into two separate session parameters for

   those participants which are active data senders and those which are

   not.  Using two parameters allows RTCP reception reports to be turned

   off entirely for a particular session by setting the RTCP bandwidth

   for non-data-senders to zero while keeping the RTCP bandwidth for

   data senders non-zero so that sender reports...