Network Working Group H. Scholz Internet-Draft VOIPFUTURE GmbH Intended status: Informational July 9, 2012 Expires: January 10, 2013 RTP Stream Quality Information Export using IPFIX draft-scholz-ipfix-rtp-audio-quality-00 Abstract This draft defines a set of Information Elements and matching Templates to convey RTP media stream quality information in IPFIX packets. The Information Elements describe the RTP quality using the R-factor and Mean Opinion score (MOS) for the entire duration of a monitored stream or for a smaller time slice thereof. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. 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 http://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 January 10, 2013. Copyright Notice Copyright (c) 2012 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Scholz Expires January 10, 2013 [Page 1] Internet-Draft RTP Streams in IPFIX July 2012 This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1.1. Quality of Service (QoS) Monitoring . . . . . . . . . 3 1.1.2. Service Level Agreement (SLA) . . . . . . . . . . . . 3 1.1.3. Troubleshooting . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. MOS measurement . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. rtpMOSCAlg . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. rtpMOSClass1 . . . . . . . . . . . . . . . . . . . . . . . 5 3.3. rtpMOSClass2 . . . . . . . . . . . . . . . . . . . . . . . 5 3.4. rtpMOSClass3 . . . . . . . . . . . . . . . . . . . . . . . 5 3.5. rtpMOSClass4 . . . . . . . . . . . . . . . . . . . . . . . 6 3.6. rtpMOSClass5 . . . . . . . . . . . . . . . . . . . . . . . 6 3.7. rtpMinMOS . . . . . . . . . . . . . . . . . . . . . . . . 6 3.8. rtpAvgMOS . . . . . . . . . . . . . . . . . . . . . . . . 7 3.9. rtpMaxMOS . . . . . . . . . . . . . . . . . . . . . . . . 7 3.10. rtpMinRFactor . . . . . . . . . . . . . . . . . . . . . . 7 3.11. rtpAvgRFactor . . . . . . . . . . . . . . . . . . . . . . 7 3.12. rtpMaxRFactor . . . . . . . . . . . . . . . . . . . . . . 8 4. Recommended Templates . . . . . . . . . . . . . . . . . . . . 8 4.1. Entire stream . . . . . . . . . . . . . . . . . . . . . . 8 4.2. Time slice . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . . 9 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 10 Scholz Expires January 10, 2013 [Page 2] Internet-Draft RTP Streams in IPFIX July 2012 1. Introduction IPFIX [RFC5101] and [RFC5102] define a framework allowing to export arbitrary data from so called IPFIX exporters. One type of IPFIX exporter may be co-located with Session Initiation Protocol (SIP) [RFC3261] based VoIP entities or passively observe SIP based VoIP calls. The signaling messages can be exported using [I-D.trammell-ipfix-sip-msg] and Real Time Protocol (RTP) [RFC3550] media streams are covered in [I-D.akhter-ipfix-perfmon]. Media quality is out of the scope of both these documents. This document defines a set of additional IPFIX Information Elements (IEs) to describe RTP audio stream quality. 1.1. Use Cases RTP stream flow information contained in IPFIX flow records can be used for various tasks such as Quality of Service (QoS) monitoring, Service Level Agreement (SLA) validation and general troubleshooting of VoIP networks. 1.1.1. Quality of Service (QoS) Monitoring Aggregated to higher-level metrics the in-depth information provided by the RTP (and optionally SIP) flow records allow service providers to gauge the overall quality of their network in terms of the quality of experience (QoE). On this level an individual call is less important but the overall quality (e.g. amount of minutes meeting certain quality standards) can be used to get a quick overview on the network and service performance. 1.1.2. Service Level Agreement (SLA) SLAs are typically used as part of contracts between two network operators. The requirements on the reliability of the data may be higher compared to QoS Monitoring as the failure to meet contractually agreed quality standards often has a direct commercial impact. 1.1.3. Troubleshooting An active network component (SIP proxy, B2BUA, media server) may not have the capabilities to store session related information for a long time to facilitate troubleshooting capabilities (e.g. due to missing hard-disk). Such a system or a group of systems may run the metering process and export the data to a collector for processing or troubleshooting purposes. Scholz Expires January 10, 2013 [Page 3] Internet-Draft RTP Streams in IPFIX July 2012 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 3. MOS measurement A multitude of Mean Opinion Score (MOS) assessment algorithms have been defined of which only one or few may be available to an IPFIX Metering Process. The quality (i.e. accuracy) of these algorithms varies and has to be noted when transporting MOS values. An IPFIX Metering Process may use these Information Elements to convey information on the duration of the stream in which the quality fell into the respective category as well as the measurement algorithm used to obtain the information. 3.1. rtpMOSCAlg The values carried in this IE are taken from the "RTCP XR QoE metric block - Calculation Algorithm" sub-registry of the "RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry" as defined in [I-D.wu-xrblock-rtcp-xr-quality-monitoring]. Even when an algorithm other than G.107 is used the rtpMOSClassN Information Elements use the R-Factor based classes as defined in the G.107 documentation. Description: The calculation algorithm (CAlg) used by the Metering Process to calculate the MOS value. 0: undefined: The algorithm is not known/specified. 1: ITU-T P.564 2: G.107 3: G.107 / ETSI TS 101 329-5 Annex E 4: ITU-T P.NAMS 5: ITU-T P.NBAMS Scholz Expires January 10, 2013 [Page 4] Internet-Draft RTP Streams in IPFIX July 2012 6: RTCP - Real Time Control Protocol (not fefined in registry!) Data Type: unsigned8 Data Type Semantics: identifier PEN (provisional): tbd ElementId (provisional): tbd The MOS values calculated are separated into MOS classes based on the ITU-T G.107 classes. 3.2. rtpMOSClass1 Description: Number of seconds the monitored stream had a MOS quality lower than 3.10 Data Type: float32 Data Type Semantics: deltaCounter PEN (provisional): tbd ElementId (provisional): tbd 3.3. rtpMOSClass2 Description: Number of seconds the monitored stream had a MOS quality larger than or equal 3.10 and lower than 3.60 Data Type: float32 Data Type Semantics: deltaCounter PEN (provisional): tbd ElementId (provisional): tbd 3.4. rtpMOSClass3 Description: Number of seconds the monitored stream had a MOS quality larger than or equal 3.60 and lower than 4.03 Data Type: float32 Scholz Expires January 10, 2013 [Page 5] Internet-Draft RTP Streams in IPFIX July 2012 Data Type Semantics: deltaCounter PEN (provisional): tbd ElementId (provisional): tbd 3.5. rtpMOSClass4 Description: Number of seconds the monitored stream had a MOS quality larger than or equal 4.03 and lower than 4.34 Data Type: float32 Data Type Semantics: deltaCounter PEN (provisional): tbd ElementId (provisional): tbd 3.6. rtpMOSClass5 Description: Number of seconds the monitored stream had a MOS quality larger than or equal 4.34 Data Type: float32 Data Type Semantics: deltaCounter PEN (provisional): tbd ElementId (provisional): tbd 3.7. rtpMinMOS Description: Minimum MOS value measured in the monitoring interval. Data Type: float32 Data Type Semantics: quantity PEN (provisional): tbd ElementId (provisional): tbd Scholz Expires January 10, 2013 [Page 6] Internet-Draft RTP Streams in IPFIX July 2012 3.8. rtpAvgMOS Description: Average MOS value measured in the monitoring interval. Data Type: float32 Data Type Semantics: quantity PEN (provisional): tbd ElementId (provisional): tbd 3.9. rtpMaxMOS Description: Maximum MOS value measured in the monitoring interval. Data Type: float32 Data Type Semantics: quantity PEN (provisional): tbd ElementId (provisional): tbd 3.10. rtpMinRFactor Description: Minimum R-Factor measured in the monitoring interval. Data Type: float32 Data Type Semantics: quantity PEN (provisional): tbd ElementId (provisional): tbd 3.11. rtpAvgRFactor Description: Average R-Factor measured in the monitoring interval. Data Type: float32 Data Type Semantics: quantity PEN (provisional): tbd Scholz Expires January 10, 2013 [Page 7] Internet-Draft RTP Streams in IPFIX July 2012 ElementId (provisional): tbd 3.12. rtpMaxRFactor Description: Maximum R-Factor measured in the monitoring interval. Data Type: float32 Data Type Semantics: quantity PEN (provisional): tbd ElementId (provisional): tbd 4. Recommended Templates The defined RTP stream IPFIX templates must support both IPv4 and IPv6 transport. They need to carry either flow information regarding the entire duration of an RTP stream or specific to a shorter observation interval. The template incorporates IEs from [I-D.akhter-ipfix-perfmon] to describe the RTP stream. In order to correlate the RTP quality information with signaling information (e.g. subscriber IDs) a correlation ID may be added to the template. Note that this ID has yet to be defined and is outside the scope of this document. 4.1. Entire stream tbd 4.2. Time slice tbd, based on previous template. Split a single RTP stream in three flow records as example including (empty) 'RTP stream ended' flow record. 5. Examples tbd Scholz Expires January 10, 2013 [Page 8] Internet-Draft RTP Streams in IPFIX July 2012 6. Acknowledgements tbd 7. IANA Considerations tbd 8. Security Considerations tbd 9. References 9.1. Normative References [I-D.wu-xrblock-rtcp-xr-quality-monitoring] Hunt, G., Clark, A., Wu, W., Schott, R., and G. Zorn, "RTCP XR Blocks for QoE metric reporting", draft-wu-xrblock-rtcp-xr-quality-monitoring-06 (work in progress), December 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5101] Claise, B., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008. [RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. Meyer, "Information Model for IP Flow Information Export", RFC 5102, January 2008. 9.2. Informative References [I-D.akhter-ipfix-perfmon] Akhter, A., "Information Elements for Flow Performance Measurement", draft-akhter-ipfix-perfmon-00 (work in progress), October 2010. [I-D.trammell-ipfix-sip-msg] Claise, B., Trammell, B., Kaplan, H., and S. Niccolini, "SIP Message Information Export using IPFIX", draft-trammell-ipfix-sip-msg-02 (work in progress), October 2011. Scholz Expires January 10, 2013 [Page 9] Internet-Draft RTP Streams in IPFIX July 2012 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003. Author's Address Hendrik Scholz VOIPFUTURE GmbH Wendenstrasse 4 Hamburg 20097 Germany Phone: +49 40 688 900 100 Email: hscholz@voipfuture.com URI: http://www.voipfuture.com/ Scholz Expires January 10, 2013 [Page 10]