--- 1/draft-ietf-rmcat-sbd-10.txt 2018-03-29 09:13:21.385674396 -0700 +++ 2/draft-ietf-rmcat-sbd-11.txt 2018-03-29 09:13:21.433675539 -0700 @@ -1,23 +1,23 @@ RTP Media Congestion Avoidance Techniques D. Hayes, Ed. Internet-Draft Simula Research Laboratory Intended status: Experimental S. Ferlin -Expires: August 20, 2018 +Expires: September 30, 2018 M. Welzl K. Hiorth University of Oslo - February 16, 2018 + March 29, 2018 Shared Bottleneck Detection for Coupled Congestion Control for RTP Media. - draft-ietf-rmcat-sbd-10 + draft-ietf-rmcat-sbd-11 Abstract This document describes a mechanism to detect whether end-to-end data flows share a common bottleneck. It relies on summary statistics that are calculated based on continuous measurements and used as input to a grouping algorithm that runs wherever the knowledge is needed. Status of This Memo @@ -28,21 +28,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on August 20, 2018. + This Internet-Draft will expire on September 30, 2018. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -125,31 +125,33 @@ The current Internet is unable to explicitly inform endpoints as to which flows share bottlenecks, so endpoints need to infer this from whatever information is available to them. The mechanism described here currently utilizes packet loss and packet delay, but is not restricted to these. As ECN becomes more prevalent it too will become a valuable base signal. 1.2.1. Packet Loss - Packet loss is often a relatively rare signal. Therefore, on its own - it is of limited use for SBD, however, it is a valuable supplementary - measure when it is more prevalent. + Packet loss is often a relatively infrequent indication that a flow + traverses a bottleneck. Therefore, on its own it is of limited use + for SBD, however, it is a valuable supplementary measure when it is + more prevalent (refer to [RFC2680] section 2.5 for measuring packet + loss). 1.2.2. Packet Delay End-to-end delay measurements include noise from every device along the path in addition to the delay perturbation at the bottleneck device. The noise is often significantly increased if the round-trip time is used. The cleanest signal is obtained by using One-Way-Delay - (OWD). + (OWD) (refer to [RFC7679] section 3 for a definition of OWD). Measuring absolute OWD is difficult since it requires both the sender and receiver clocks to be synchronized. However, since the statistics being collected are relative to the mean OWD, a relative OWD measurement is sufficient. Clock skew is not usually significant over the time intervals used by this SBD mechanism (see [RFC6817] A.2 for a discussion on clock skew and OWD measurements). However, in circumstances where it is significant, Section 5.2 outlines a way of adjusting the calculations to cater for it. @@ -918,20 +920,22 @@ for coupled congestion control as described in [I-D.ietf-rmcat-coupled-cc], the security considerations of [I-D.ietf-rmcat-coupled-cc] apply. 10. Change history XX RFC ED - PLEASE REMOVE THIS SECTION XXX Changes made to this document: + WG-10->WG-11 : Genart review addressed. + WG-09->WG-10 : AD review addressed. WG-08->WG-09 : Removed definitions that are no longer used. Added pkt_loss definition. Refined c_s recommendation. WG-07->WG-08 : Updates addressing https://www.ietf.org/mail- archive/web/rmcat/current/msg01671.html Mainly clarifications. WG-06->WG-07 : Updates addressing @@ -1005,28 +1009,33 @@ Hayes, D., Ferlin, S., and M. Welzl, "Practical Passive Shared Bottleneck Detection using Shape Summary Statistics", Proc. the IEEE Local Computer Networks (LCN) pp150-158, September 2014, . [I-D.ietf-avtcore-cc-feedback-message] Sarker, Z., Perkins, C., Singh, V., and M. Ramalho, "RTP Control Protocol (RTCP) Feedback for Congestion Control", - draft-ietf-avtcore-cc-feedback-message-00 (work in - progress), October 2017. + draft-ietf-avtcore-cc-feedback-message-01 (work in + progress), March 2018. [I-D.ietf-rmcat-coupled-cc] Islam, S., Welzl, M., and S. Gjessing, "Coupled congestion control for RTP media", draft-ietf-rmcat-coupled-cc-07 (work in progress), September 2017. + [RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way + Packet Loss Metric for IPPM", RFC 2680, + DOI 10.17487/RFC2680, September 1999, + . + [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, July 2003, . [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, "Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, DOI 10.17487/RFC4585, July 2006, . @@ -1034,20 +1043,25 @@ [RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)", RFC 5124, DOI 10.17487/RFC5124, February 2008, . [RFC6817] Shalunov, S., Hazel, G., Iyengar, J., and M. Kuehlewind, "Low Extra Delay Background Transport (LEDBAT)", RFC 6817, DOI 10.17487/RFC6817, December 2012, . + [RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton, + Ed., "A One-Way Delay Metric for IP Performance Metrics + (IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January + 2016, . + [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [Zhang-Infocom02] Zhang, L., Liu, Z., and H. Xia, "Clock synchronization algorithms for network measurements", Proc. the IEEE International Conference on Computer Communications (INFOCOM) pp160-169, September 2002, .