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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...