Sending Multiple Media Streams in a Single RTP Session
draft-ietf-avtcore-rtp-multi-stream-03
AVTCORE J. Lennox
Internet-Draft Vidyo
Updates: 3550, 4585 (if approved) M. Westerlund
Intended status: Standards Track Ericsson
Expires: August 18, 2014 Q. Wu
Huawei
C. Perkins
University of Glasgow
February 14, 2014
Sending Multiple Media Streams in a Single RTP Session
draft-ietf-avtcore-rtp-multi-stream-03
Abstract
This document expands and clarifies the behavior of the Real-Time
Transport Protocol (RTP) endpoints when they are using multiple
synchronization sources (SSRCs), e.g. for sending multiple media
streams, in a single RTP session. In particular, issues involving
RTCP Control Protocol (RTCP) messages are described.
This document updates RFC 3550 in regards to handling of multiple
SSRCs per endpoint in RTP sessions. It also updates RFC 4585 to
clarify the calculation of the timeout of SSRCs and the inclusion of
feeback messages.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 18, 2014.
Lennox, et al. Expires August 18, 2014 [Page 1]
Internet-Draft Multiple Media Streams in an RTP Session February 2014
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases For Multi-Stream Endpoints . . . . . . . . . . . . 4
3.1. Multiple-Capturer Endpoints . . . . . . . . . . . . . . . 4
3.2. Multi-Media Sessions . . . . . . . . . . . . . . . . . . 4
3.3. Multi-Stream Mixers . . . . . . . . . . . . . . . . . . . 4
3.4. Multiple SSRCs for a Single Media Source . . . . . . . . 5
4. Multi-Stream Endpoint RTP Media Recommendations . . . . . . . 5
5. Multi-Stream Endpoint RTCP Recommendations . . . . . . . . . 5
5.1. RTCP Reporting Requirement . . . . . . . . . . . . . . . 5
5.2. Initial Reporting Interval . . . . . . . . . . . . . . . 6
5.3. Compound RTCP Packets . . . . . . . . . . . . . . . . . . 6
5.3.1. Maintaining AVG_RTCP_SIZE . . . . . . . . . . . . . . 7
5.3.2. Scheduling RTCP with Multiple Reporting SSRCs . . . . 8
5.4. RTP/AVPF Feedback Packets . . . . . . . . . . . . . . . . 10
5.4.1. The SSRC Used . . . . . . . . . . . . . . . . . . . . 10
5.4.2. Scheduling a Feedback Packet . . . . . . . . . . . . 11
6. RTCP Considerations for Streams with Disparate Rates . . . . 12
6.1. Timing out SSRCs . . . . . . . . . . . . . . . . . . . . 13
6.2. Tuning RTCP transmissions . . . . . . . . . . . . . . . . 14
6.2.1. RTP/AVP and RTP/SAVP . . . . . . . . . . . . . . . . 14
6.2.2. RT/AVPF and RTP/SAVPF . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 17
8. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 17
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1. Normative References . . . . . . . . . . . . . . . . . . 18
10.2. Informative References . . . . . . . . . . . . . . . . . 18
Appendix A. Changes From Earlier Versions . . . . . . . . . . . 19
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