draft-ietf-avtcore-rtp-circuit-breakers-03.txt   draft-ietf-avtcore-rtp-circuit-breakers-04.txt 
AVTCORE Working Group C. S. Perkins AVTCORE Working Group C. S. Perkins
Internet-Draft University of Glasgow Internet-Draft University of Glasgow
Updates: 3550 (if approved) V. Singh Updates: 3550 (if approved) V. Singh
Intended status: Standards Track Aalto University Intended status: Standards Track Aalto University
Expires: January 16, 2014 July 15, 2013 Expires: July 17, 2014 January 13, 2014
Multimedia Congestion Control: Circuit Breakers for Unicast RTP Sessions Multimedia Congestion Control: Circuit Breakers for Unicast RTP Sessions
draft-ietf-avtcore-rtp-circuit-breakers-03 draft-ietf-avtcore-rtp-circuit-breakers-04
Abstract Abstract
The Real-time Transport Protocol (RTP) is widely used in telephony, The Real-time Transport Protocol (RTP) is widely used in telephony,
video conferencing, and telepresence applications. Such applications video conferencing, and telepresence applications. Such applications
are often run on best-effort UDP/IP networks. If congestion control are often run on best-effort UDP/IP networks. If congestion control
is not implemented in the applications, then network congestion will is not implemented in the applications, then network congestion will
deteriorate the user's multimedia experience. This document does not deteriorate the user's multimedia experience. This document does not
propose a congestion control algorithm; instead, it defines a minimal propose a congestion control algorithm; instead, it defines a minimal
set of RTP "circuit-breakers". Circuit-breakers are conditions under set of RTP "circuit-breakers". Circuit-breakers are conditions under
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Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. RTP Circuit Breakers for Systems Using the RTP/AVP Profile . 6 4. RTP Circuit Breakers for Systems Using the RTP/AVP Profile . 5
4.1. RTP/AVP Circuit Breaker #1: Media Timeout . . . . . . . . 7 4.1. RTP/AVP Circuit Breaker #1: Media Timeout . . . . . . . . 7
4.2. RTP/AVP Circuit Breaker #2: RTCP Timeout . . . . . . . . 8 4.2. RTP/AVP Circuit Breaker #2: RTCP Timeout . . . . . . . . 8
4.3. RTP/AVP Circuit Breaker #3: Congestion . . . . . . . . . 9 4.3. RTP/AVP Circuit Breaker #3: Congestion . . . . . . . . . 9
4.4. Ceasing Transmission . . . . . . . . . . . . . . . . . . 12 4.4. Ceasing Transmission . . . . . . . . . . . . . . . . . . 12
5. RTP Circuit Breakers for Systems Using the RTP/AVPF Profile . 12 5. RTP Circuit Breakers for Systems Using the RTP/AVPF Profile . 12
6. Impact of RTCP XR . . . . . . . . . . . . . . . . . . . . . . 13 6. Impact of RTCP XR . . . . . . . . . . . . . . . . . . . . . . 13
7. Impact of RTCP Reporting Groups . . . . . . . . . . . . . . . 14 7. Impact of RTCP Reporting Groups . . . . . . . . . . . . . . . 13
8. Impact of Explicit Congestion Notification (ECN) . . . . . . 14 8. Impact of Explicit Congestion Notification (ECN) . . . . . . 14
9. Security Considerations . . . . . . . . . . . . . . . . . . . 14 9. Security Considerations . . . . . . . . . . . . . . . . . . . 14
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
12.1. Normative References . . . . . . . . . . . . . . . . . . 15 12.1. Normative References . . . . . . . . . . . . . . . . . . 15
12.2. Informative References . . . . . . . . . . . . . . . . . 15 12.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
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the sender. However, if a receiver detects the onset of the sender. However, if a receiver detects the onset of
congestion partway through a reporting interval, the base RTP congestion partway through a reporting interval, the base RTP
specification contains no provision for sending the RTCP RR packet specification contains no provision for sending the RTCP RR packet
early, and the receiver has to wait until the next scheduled early, and the receiver has to wait until the next scheduled
reporting interval. reporting interval.
o The RTCP Extended Reports (XR) [RFC3611] allow reporting of more o The RTCP Extended Reports (XR) [RFC3611] allow reporting of more
complex and sophisticated reception quality metrics, but do not complex and sophisticated reception quality metrics, but do not
change the RTCP timing rules. RTCP extended reports of potential change the RTCP timing rules. RTCP extended reports of potential
interest for congestion control purposes are the extended packet interest for congestion control purposes are the extended packet
loss, discard, and burst metrics [RFC3611], loss, discard, and burst metrics [RFC3611], [RFC7002], [RFC7097],
[I-D.ietf-xrblock-rtcp-xr-discard], [RFC7003], [RFC6958]; and the extended delay metrics [RFC6843],
[I-D.ietf-xrblock-rtcp-xr-discard-rle-metrics], [RFC6798]. Other RTCP Extended Reports that could be helpful for
[I-D.ietf-xrblock-rtcp-xr-burst-gap-discard], congestion control purposes might be developed in future.
[I-D.ietf-xrblock-rtcp-xr-burst-gap-loss]; and the extended delay
metrics [RFC6843], [RFC6798]. Other RTCP Extended Reports that
could be helpful for congestion control purposes might be
developed in future.
o Rapid feedback about the occurrence of congestion events can be o Rapid feedback about the occurrence of congestion events can be
achieved using the Extended RTP Profile for RTCP-Based Feedback achieved using the Extended RTP Profile for RTCP-Based Feedback
(RTP/AVPF) [RFC4585] in place of the more common RTP/AVP profile (RTP/AVPF) [RFC4585] in place of the more common RTP/AVP profile
[RFC3551]. This modifies the RTCP timing rules to allow RTCP [RFC3551]. This modifies the RTCP timing rules to allow RTCP
reports to be sent early, in some cases immediately, provided the reports to be sent early, in some cases immediately, provided the
average RTCP reporting interval remains unchanged. It also average RTCP reporting interval remains unchanged. It also
defines new transport-layer feedback messages, including negative defines new transport-layer feedback messages, including negative
acknowledgements (NACKs), that can be used to report on specific acknowledgements (NACKs), that can be used to report on specific
congestion events. The use of the RTP/AVPF profile is dependent congestion events. The use of the RTP/AVPF profile is dependent
skipping to change at page 16, line 10 skipping to change at page 16, line 10
Applications", Proc. ACM SIGCOMM 2000, DOI 10.1145/ Applications", Proc. ACM SIGCOMM 2000, DOI 10.1145/
347059.347397, August 2000. 347059.347397, August 2000.
[I-D.ietf-avtcore-rtp-multi-stream-optimisation] [I-D.ietf-avtcore-rtp-multi-stream-optimisation]
Lennox, J., Westerlund, M., Wu, W., and C. Perkins, Lennox, J., Westerlund, M., Wu, W., and C. Perkins,
"Sending Multiple Media Streams in a Single RTP Session: "Sending Multiple Media Streams in a Single RTP Session:
Grouping RTCP Reception Statistics and Other Feedback", Grouping RTCP Reception Statistics and Other Feedback",
draft-ietf-avtcore-rtp-multi-stream-optimisation-00 (work draft-ietf-avtcore-rtp-multi-stream-optimisation-00 (work
in progress), July 2013. in progress), July 2013.
[I-D.ietf-xrblock-rtcp-xr-burst-gap-discard]
Clark, A., Huang, R., and W. Wu, "RTP Control
Protocol(RTCP) Extended Report (XR) Block for Burst/Gap
Discard metric Reporting", draft-ietf-xrblock-rtcp-xr-
burst-gap-discard-14 (work in progress), April 2013.
[I-D.ietf-xrblock-rtcp-xr-burst-gap-loss]
Clark, A., Zhang, S., Zhao, J., and W. Wu, "RTP Control
Protocol (RTCP) Extended Report (XR) Block for Burst/Gap
Loss metric Reporting", draft-ietf-xrblock-rtcp-xr-burst-
gap-loss-12 (work in progress), April 2013.
[I-D.ietf-xrblock-rtcp-xr-discard-rle-metrics]
Ott, J., Singh, V., and I. Curcio, "RTP Control Protocol
(RTCP) Extended Reports (XR) for Run Length Encoding (RLE)
of Discarded Packets", draft-ietf-xrblock-rtcp-xr-discard-
rle-metrics-06 (work in progress), July 2013.
[I-D.ietf-xrblock-rtcp-xr-discard]
Clark, A., Zorn, G., and W. Wu, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Discard Count metric
Reporting", draft-ietf-xrblock-rtcp-xr-discard-15 (work in
progress), June 2013.
[Padhye] Padhye, J., Firoiu, V., Towsley, D., and J. Kurose, [Padhye] Padhye, J., Firoiu, V., Towsley, D., and J. Kurose,
"Modeling TCP Throughput: A Simple Model and its Empirical "Modeling TCP Throughput: A Simple Model and its Empirical
Validation", Proc. ACM SIGCOMM 1998, DOI 10.1145/ Validation", Proc. ACM SIGCOMM 1998, DOI 10.1145/
285237.285291, August 1998. 285237.285291, August 1998.
[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP", RFC of Explicit Congestion Notification (ECN) to IP", RFC
3168, September 2001. 3168, September 2001.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
skipping to change at page 17, line 27 skipping to change at page 16, line 49
for RTP over UDP", RFC 6679, August 2012. for RTP over UDP", RFC 6679, August 2012.
[RFC6798] Clark, A. and Q. Wu, "RTP Control Protocol (RTCP) Extended [RFC6798] Clark, A. and Q. Wu, "RTP Control Protocol (RTCP) Extended
Report (XR) Block for Packet Delay Variation Metric Report (XR) Block for Packet Delay Variation Metric
Reporting", RFC 6798, November 2012. Reporting", RFC 6798, November 2012.
[RFC6843] Clark, A., Gross, K., and Q. Wu, "RTP Control Protocol [RFC6843] Clark, A., Gross, K., and Q. Wu, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Delay Metric (RTCP) Extended Report (XR) Block for Delay Metric
Reporting", RFC 6843, January 2013. Reporting", RFC 6843, January 2013.
[RFC6958] Clark, A., Zhang, S., Zhao, J., and Q. Wu, "RTP Control
Protocol (RTCP) Extended Report (XR) Block for Burst/Gap
Loss Metric Reporting", RFC 6958, May 2013.
[RFC7002] Clark, A., Zorn, G., and Q. Wu, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Discard Count Metric
Reporting", RFC 7002, September 2013.
[RFC7003] Clark, A., Huang, R., and Q. Wu, "RTP Control Protocol
(RTCP) Extended Report (XR) Block for Burst/Gap Discard
Metric Reporting", RFC 7003, September 2013.
[RFC7097] Ott, J., Singh, V., and I. Curcio, "RTP Control Protocol
(RTCP) Extended Report (XR) for RLE of Discarded Packets",
RFC 7097, January 2014.
Authors' Addresses Authors' Addresses
Colin Perkins Colin Perkins
University of Glasgow University of Glasgow
School of Computing Science School of Computing Science
Glasgow G12 8QQ Glasgow G12 8QQ
United Kingdom United Kingdom
Email: csp@csperkins.org Email: csp@csperkins.org
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