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diff --git a/doc/rfc/rfc6776.txt b/doc/rfc/rfc6776.txt new file mode 100644 index 0000000..780a9ba --- /dev/null +++ b/doc/rfc/rfc6776.txt @@ -0,0 +1,507 @@ + + + + + + +Internet Engineering Task Force (IETF) A. Clark +Request for Comments: 6776 Telchemy +Category: Standards Track Q. Wu +ISSN: 2070-1721 Huawei + October 2012 + + + Measurement Identity and Information Reporting Using a + Source Description (SDES) Item and an RTCP Extended Report (XR) Block + +Abstract + + This document defines an RTP Control Protocol (RTCP) Source + Description (SDES) item and an RTCP Extended Report (XR) block + carrying parameters that identify and describe a measurement period + to which one or more other RTCP XR blocks may refer. + +Status of This Memo + + This is an Internet Standards Track document. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Further information on + Internet Standards is available in Section 2 of RFC 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc6776. + +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. + + + + + + +Clark & Wu Standards Track [Page 1] + +RFC 6776 Measurement Identity and Duration October 2012 + + +Table of Contents + + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 + 1.1. RTCP and RTCP XRs . . . . . . . . . . . . . . . . . . . . . 3 + 1.2. Performance Metrics Framework . . . . . . . . . . . . . . . 3 + 1.3. Applicability . . . . . . . . . . . . . . . . . . . . . . . 3 + 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4 + 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 + 3. Measurement Identity SDES Item . . . . . . . . . . . . . . . . 4 + 3.1. APSI: Application-Specific Identifier SDES Item . . . . . . 4 + 4. Measurement Information XR Block . . . . . . . . . . . . . . . 5 + 4.1. Report Block Structure . . . . . . . . . . . . . . . . . . 5 + 4.2. Definition of Fields in Measurement Information Report + Block . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 + 5.1. New RTCP SDES Item Type Value . . . . . . . . . . . . . . . 7 + 5.2. New RTCP XR Block Type Value . . . . . . . . . . . . . . . 7 + 5.3. Contact Information for Registrations . . . . . . . . . . . 7 + 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 + 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 + 7.1. Normative References . . . . . . . . . . . . . . . . . . . 8 + 7.2. Informative References . . . . . . . . . . . . . . . . . . 8 + +1. Introduction + + This document defines one new RTP Control Protocol (RTCP) Source + Description (SDES) [RFC3550] item and one new Extended Report (XR) + block carrying parameters that identify and describe a measurement + period to which one or more other RTCP XR blocks may refer. + + The SDES item provides a field for an application-specific auxiliary + identifier. This identifier may be used to correlate data in XR + blocks within an RTP session with data from a non-RTP session. + + An RTCP Measurement Identity SDES packet may be associated with a set + of RTCP XR metrics blocks that share the same application-specific + measurement identifier. + + The XR block does not contain any measurement results (metrics). + Instead, it provides information relevant to a measurement reported + in one or more other block types, including: + + o the sequence number of the first packet of the RTP session, + + o the extended sequence numbers of the first packet of the current + measurement interval, and the last packet included in the + measurement, + + + + +Clark & Wu Standards Track [Page 2] + +RFC 6776 Measurement Identity and Duration October 2012 + + + o the duration of the most recent measurement interval, and + + o the duration of the interval applicable to cumulative measurements + (which may be the duration of the RTP session to date). + + The calculation method of the extended RTP sequence number is + provided in the Real-time Transport Protocol (RTP) [RFC3550]. + + The RTCP XR block containing the measurement information is intended + to provide a single copy of the information necessary to relate + measurement data in the RTCP XR blocks to the stream and measurement + period to which they refer. Commonly, multiple other small metric + blocks contain measurement data for the same stream and period, and + overhead would be large if all of these metric blocks carried + duplicated data for measurement identification. + + The RTCP XR block may be associated with a set of RTCP XR metrics + blocks that share the same information relevant to a reported + measurement. There may be several such sets in an RTCP packet, in + which each set shares the same information relevant to a reported + measurement. There may also be RTCP XR blocks in the packet that are + not associated with a Measurement Information block, for example, + blocks that were defined before the Measurement Identity and + information mechanism were introduced by this document. + +1.1. RTCP and RTCP XRs + + The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] + defines an extensible structure for reporting by using an RTCP XR. + [RFC3611] also defines the use of XR blocks. This document defines a + new Extended Report block. + +1.2. Performance Metrics Framework + + The Performance Metrics Framework [RFC6390] provides guidance on the + definition and specification of performance metrics. The RTP + Monitoring Architectures [MONARCH] provides guidelines for reporting + block format using RTCP XR. The SDES item and XR block described in + this document are in accordance with [RFC6390] and [MONARCH]. + +1.3. Applicability + + The RTCP SDES item and the RTCP XR block defined in this document + provide information relevant to the measurements for members of a + family of RTCP XR metrics blocks that are designed to use it. To use + the mechanism defined here, the RTCP XR block containing measurement + information is not required to be in the same RTCP packet as the SDES + item containing measurement identity. + + + +Clark & Wu Standards Track [Page 3] + +RFC 6776 Measurement Identity and Duration October 2012 + + +2. Terminology + +2.1. Standards Language + + 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. Measurement Identity SDES Item + + This section defines the format of the Measurement Identity SDES + item. The SDES item is carried in the RTCP SDES packet. The packet + format for the RTCP SDES is defined in Section 6.5 of [RFC3550]. + Each SDES packet is composed of a header with fixed-length fields for + version, source count, packet type (PT), and length, followed by zero + or more SDES items. In the SDES packet, the PT field is set to SDES + (202). + +3.1. APSI: Application-Specific Identifier SDES Item + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | APSI=10 | length |application-specific identifier + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | .... + +-+-+-+-+-+-+-+-+ + + The application-specific identifier is an additional identifier that + is useful in the context of a specific application, e.g., an MPEG-2 + transport identifier [MPEG2]. This item MUST be ignored by + applications that are not configured to make use of it. The + identifier is variable length. Its length is described by the length + field. The value of the length field does not include the two-octet + SDES item header. + + + + + + + + + + + + + + + + +Clark & Wu Standards Track [Page 4] + +RFC 6776 Measurement Identity and Duration October 2012 + + +4. Measurement Information XR Block + +4.1. Report Block Structure + + 0 1 2 3 + 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | BT=14 | Reserved | block length = 7 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | SSRC of stream source | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Reserved | first sequence number | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | extended first sequence number of interval | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | extended last sequence number | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Measurement Duration (Interval) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Measurement Duration (Cumulative) - Seconds (bit 0-31) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Measurement Duration (Cumulative) - Fraction (bit 0-31) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Report Block Structure + +4.2. Definition of Fields in Measurement Information Report Block + + Block type (BT): 8 bits + + A Measurement Information Block is identified by the constant 14. + + Reserved: 8 bits + + These bits are reserved. They MUST be set to zero by senders and + ignored by receivers. + + Block Length: 16 bits + + The length of this report block in 32-bit words minus one. For + the Measurement Information Block, the block length is equal to 7. + + SSRC of source: 32 bits + + As defined in Section 4.1 of [RFC3611]. + + + + + + +Clark & Wu Standards Track [Page 5] + +RFC 6776 Measurement Identity and Duration October 2012 + + + Reserved: 16 bits + + These bits are reserved. They MUST be set to zero by senders and + ignored by receivers. + + First sequence number: 16 bits + + The RTP sequence number of the first received RTP packet of the + session, used to determine the number of packets contributing to + cumulative measurements. + + Extended first sequence number of interval: 32 bits + + The extended RTP sequence number of the first received RTP packet + of the current measurement interval. The extended sequence number + is expressed as the low 16-bit value containing the sequence + number received in an RTP data packet and the most significant + 16-bit value containing the corresponding count of sequence number + cycles. For additional information on extended sequence numbers, + see the "extended highest sequence number received" definition in + Section 6.4.1 of RFC 3550 and Appendix A.1 of RFC 3550. + + Extended last sequence number: 32 bits + + The extended RTP sequence number of the last received RTP packet + that contributed to this measurement. The extended sequence + number is expressed as the low 16-bit value containing the + sequence number received in an RTP data packet and the most + significant 16-bit value containing the corresponding count of + sequence number cycles. For additional information on extended + sequence numbers, see the "extended highest sequence number + received" definition in Section 6.4.1 of RFC 3550 and Appendix A.1 + of RFC 3550. + + Measurement Duration (Interval): 32 bits + + The duration, expressed in units of 1/65536 seconds, of the + reporting interval applicable to Interval reports that use this + Measurement Information Block. The value of this field can be + calculated by the receiver of the RTP media stream, for example, + based on received RTP media packets or using the RTCP method + described in [RFC3550]. + + + + + + + + + +Clark & Wu Standards Track [Page 6] + +RFC 6776 Measurement Identity and Duration October 2012 + + + Measurement Duration (Cumulative): 64 bits + + The duration of the reporting interval applicable to Cumulative + reports that use this Measurement Information Block. The value of + this field is represented using a 64-bit NTP-format timestamp as + defined in [RFC5905], which is a 64-bit unsigned fixed-point + number with the integer part in the first 32 bits and the + fractional part in the last 32 bits. It can be calculated by the + receiver of the RTP media stream, for example, based on received + RTP media packets or using the RTCP method described in [RFC3550]. + +5. IANA Considerations + + A new SDES item type for RTCP SDES and a new XR block type for RTCP + XR have been registered with IANA. For general guidelines on IANA + considerations, refer to [RFC3550] for RTCP SDES and [RFC3611] for + RTCP XR. + +5.1. New RTCP SDES Item Type Value + + This document adds the Measurement Identity SDES item to the IANA + "RTP SDES item types" registry as follows: + + abbrev. name value + APSI Application-Specific Identifier 10 + +5.2. New RTCP XR Block Type Value + + This document assigns the block type value 14 in the IANA "RTCP XR + Block Type Registry" to the "Measurement Information Block". + +5.3. Contact Information for Registrations + + The contact information for the registrations is: + + Qin Wu (sunseawq@huawei.com) + 101 Software Avenue, Yuhua District + Nanjing, Jiangsu 210012 + China + +6. Security Considerations + + RTCP reports can contain sensitive information, including information + about the nature and duration of a session established between two or + more endpoints. Therefore, the use of security mechanisms with RTP, + as documented in Section 9 of [RFC3550], applies. + + + + + +Clark & Wu Standards Track [Page 7] + +RFC 6776 Measurement Identity and Duration October 2012 + + +7. References + +7.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. + Jacobson, "RTP: A Transport Protocol for Real-Time + Applications", STD 64, RFC 3550, July 2003. + + [RFC3611] Friedman, T., Ed., Caceres, R., Ed., and A. Clark, Ed., + "RTP Control Protocol Extended Reports (RTCP XR)", + RFC 3611, November 2003. + + [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, + "Network Time Protocol Version 4: Protocol and Algorithms + Specification", RFC 5905, June 2010. + +7.2. Informative References + + [MONARCH] Wu, Q., Hunt, G., and P. Arden, "Monitoring Architectures + for RTP", Work in Progress, September 2012. + + [MPEG2] ISO/IEC, "Standard 13818-1, Information technology -- + Generic coding of moving pictures and associated audio + information: Systems", October 2007. + + [RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New + Performance Metric Development", BCP 170, RFC 6390, + October 2011. + + + + + + + + + + + + + + + + + + + + +Clark & Wu Standards Track [Page 8] + +RFC 6776 Measurement Identity and Duration October 2012 + + +Authors' Addresses + + Alan Clark + Telchemy Incorporated + 2905 Premiere Parkway, Suite 280 + Duluth, GA 30097 + United States + + EMail: alan.d.clark@telchemy.com + + + Qin Wu + Huawei + 101 Software Avenue, Yuhua District + Nanjing, Jiangsu 210012 + China + + EMail: sunseawq@huawei.com + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Clark & Wu Standards Track [Page 9] + |