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rfc:rfc7380

Internet Engineering Task Force (IETF) J. Tong Request for Comments: 7380 C. Bi, Ed. Category: Standards Track China Telecom ISSN: 2070-1721 R. Even

                                                            Q. Wu, Ed.
                                                              R. Huang
                                                                Huawei
                                                         November 2014
  RTP Control Protocol (RTCP) Extended Report (XR) Block for MPEG2

Transport Stream (TS) Program Specific Information (PSI) Decodability

                    Statistics Metrics Reporting

Abstract

 An MPEG2 Transport Stream (TS) is a standard container format used in
 the transmission and storage of multimedia data.  Unicast/multicast
 MPEG2 TS over RTP is widely deployed in IPTV systems.  This document
 defines an RTP Control Protocol (RTCP) Extended Report (XR) block
 that allows the reporting of MPEG2 TS decodability statistics metrics
 related to transmissions of MPEG2 TS over RTP.  The metrics specified
 in the RTCP XR block are related to Program Specific Information
 (PSI) carried in MPEG TS.

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/rfc7380.

Tong, et al. Standards Track [Page 1] RFC 7380 RTCP XR TS Decodability November 2014

Copyright Notice

 Copyright (c) 2014 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.

Table of Contents

 1. Introduction ....................................................3
    1.1. MPEG2 Transport Stream Decodability Metrics ................3
    1.2. RTCP and RTCP XR Reports ...................................3
    1.3. Performance Metrics Framework ..............................3
    1.4. Applicability ..............................................3
 2. Terminology .....................................................4
    2.1. Standards Language .........................................4
 3. MPEG2 TS PSI Decodability Statistics Metrics Block ..............4
 4. SDP Signaling ...................................................8
    4.1. SDP rtcp-xr-attrib Attribute Extension .....................8
    4.2. Offer/Answer Usage .........................................8
    4.3. Usage Outside of Offer/Answer ..............................8
 5. IANA Considerations .............................................9
    5.1. New RTCP XR Block Type Value ...............................9
    5.2. New RTCP XR SDP Parameter ..................................9
    5.3. Contact Information for Registrations ......................9
 6. Security Considerations .........................................9
 7. References ......................................................9
    7.1. Normative References .......................................9
    7.2. Informative References ....................................10
Authors' Addresses .................................................11

Tong, et al. Standards Track [Page 2] RFC 7380 RTCP XR TS Decodability November 2014

1. Introduction

1.1. MPEG2 Transport Stream Decodability Metrics

 The European Telecommunications Standards Institute (ETSI) has
 defined a set of syntax and information consistency tests and
 corresponding indicators [ETSI] that are recommended for the
 monitoring of MPEG2 Transport Streams [ISO-IEC.13818-1.2007].  The
 tests and corresponding indicators are grouped according to priority:
 First priority:  Necessary for decodability (basic monitoring)
 Second priority:  Recommended for continuous or periodic monitoring
 Third priority:  Recommended for application-dependent monitoring
 This memo defines a new block type for use with MPEG2 Transport
 Streams [ISO-IEC.13818-1.2007] to augment those defined in [RFC3611].
 The new block type supports reporting of the number of occurrences of
 each Program Specific Information (PSI) indicator in the first and
 second priorities listed in Sections 5.2.1 and 5.2.2, respectively,
 of [ETSI].  The third priority indicators are not supported.  The
 metrics defined here supplement information from the PSI-Independent
 Decodability Statistics Metrics Block [RFC6990].

1.2. RTCP and RTCP XR Reports

 The use of RTCP for reporting is defined in [RFC3550].  [RFC3611]
 defines an extensible structure for reporting using an RTCP Extended
 Report (XR).  This document defines a new Extended Report block for
 use with [RFC3550] and [RFC3611].

1.3. Performance Metrics Framework

 The Performance Metrics Framework [RFC6390] provides guidance on the
 definition and specification of performance metrics.  The RTP
 Monitoring Architectures [RFC6792] provides guidelines for RTCP XR
 block formats.  The new report block described in this memo is in
 compliance with the monitoring architecture specified in [RFC6792]
 and the Performance Metrics Framework [RFC6390].

1.4. Applicability

 These metrics are applicable to any type of RTP application that uses
 the MPEG2 TS standard format for multimedia data, for example, MPEG4
 over MPEG2 TS over RTP.  This new block type can be useful for
 measuring content stream or TS quality by checking TS header
 information [ETSI] and identifying the existence (and characterizing

Tong, et al. Standards Track [Page 3] RFC 7380 RTCP XR TS Decodability November 2014

 the severity) of bitstream packetization problems that may affect
 users' perception of a service delivered over RTP.  It may also be
 useful for verifying the continued correct operation of an existing
 system management tool.

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. MPEG2 TS PSI Decodability Statistics Metrics Block

 ETSI TR 101 290 [ETSI] generally defines indicators related to error
 events whereas the XR block defined in this document contains counts
 of occurrences of the [ETSI] indicators.  The block defined in this
 document reports MPEG2 TS PSI decodability statistics metrics beyond
 the information carried in the standard RTCP packet format and PSI-
 Independent Decodability Statistics Metrics Block [RFC6990], which
 are measured at the receiving end of the RTP stream.  It contains
 counts of seven metrics defined in ETSI TR 101 290 [ETSI].
 Information is reported about basic monitoring parameters necessary
 to ensure that the TS can be decoded, including:
 o  Program Association Table (PAT) errors
 o  PAT2 errors
 o  Program Map Table (PMT) errors
 o  PMT2 errors
 o  Packet Identifier (PID) errors
 Information is also reported about continuous monitoring parameters
 necessary to ensure continuous decoding, including:
 o  Cyclic Redundancy Check (CRC) errors
 o  Conditional Access Table (CAT) errors
 In these parameters, PAT2 errors and PMT2 errors are actually
 replacements for and improvements on PAT errors and PMT errors,
 respectively, and are therefore preferred in future implementations.
 In addition, measurement results for some of these parameters (e.g.,
 PAT errors or PMT errors) may be different based on whether

Tong, et al. Standards Track [Page 4] RFC 7380 RTCP XR TS Decodability November 2014

 scrambling is employed.  The other parameters defined in Section 5 of
 [ETSI] are ignored since they do not apply to all MPEG2
 implementations.  For further detailed information on these
 parameters, see [ETSI].
 The MPEG2 TS PSI Decodability Metrics Block has the following format:
     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |      BT=32    |    Reserved   |         block length          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                     SSRC of source                            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |          begin_seq            |             end_seq           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        PAT_error_count        |      PAT_error_2_count        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        PMT_error_count        |      PMT_error_2_count        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |       PID_error_count         |      CRC_error_count          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        CAT_error_count        |        Reserved               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 block type (BT): 8 bits
    The MPEG2 TS PSI Decodability Metrics Block is identified by the
    constant 32;.
 Reserved: 8 bits
    These bits are reserved.  They MUST be set to zero by senders
    ignored by receivers (see Section 4.2 of [RFC6709]).
 block length: 16 bits
    The constant 6, in accordance with the definition of this field in
    Section 3 of [RFC3611].  The block MUST be discarded if the block
    length is set to a different value.
 Synchronization Source (SSRC) of source: 32 bits
    As defined in Section 4.1 of [RFC3611].
 begin_seq: 16 bits
    As defined in Section 4.1 of [RFC3611].

Tong, et al. Standards Track [Page 5] RFC 7380 RTCP XR TS Decodability November 2014

 end_seq: 16 bits
    As defined in Section 4.1 of [RFC3611].
 PAT_error_count: 16 bits
    A count of the number of PAT errors that occurred in the above
    sequence number interval.  The Program Association Table (PAT) is
    the only packet with Packet Identifier (PID) 0x0000.  A PAT error
    occurs when (1) a packet with PID 0x0000 does not occur at least
    every 0.5 seconds, (2) a packet with PID 0x0000 does not contain
    table_id 0x00 (i.e., a PAT), or (3) the Scrambling_control_field
    in the TS packet header is not 00 for a packet with PID 0x0000.
    See Section 5.2.1 of [ETSI].  Every program within the MPEG TS
    stream is listed in the PAT; if it is missing, then no programs
    can be decoded.
    The measured value is an unsigned value.  If the measurement is
    unavailable, then the value 0xFFFF MUST be reported.  NOTE 1 of
    the table in Section 5.2.1 of [ETSI] recommends using
    PAT_error_2_count.  Upon reception, if PAT_error_2_count is
    available (that is, other than 0xFFFF), then receivers MUST ignore
    PAT_error_count.
 PAT_error_2_count: 16 bits
    A count of the number of PAT2 errors that occurred in the above
    sequence number interval.  A PAT2 error occurs when (1) a packet
    with PID 0x0000 containing table_id 0x00 does not occur at least
    every 0.5 seconds, (2) a packet with PID 0x0000 contains a table
    with a table_id other than 0x00, or (3) the
    Scrambling_control_field in the TS packet header is not 00 for a
    packet with PID 0x0000.  See Section 5.2.1 of [ETSI].
    The measured value is an unsigned value.  If the measurement is
    unavailable, then the value 0xFFFF MUST be reported.
 PMT_error_count: 16 bits
    A count of the number of PMT errors that occurred in the above
    sequence number interval.  A PMT_error occurs when (1) a packet
    containing a table with table_id 0x02 (i.e., a PMT) does not occur
    at least every 0.5 seconds on the PID that is referred to in the
    PAT or (2) the Scrambling_control_field in the TS packet header is
    not 00 for all packets with PID containing a table with table_id
    0x02 (i.e., a PMT).  See Section 5.2.1 of [ETSI].

Tong, et al. Standards Track [Page 6] RFC 7380 RTCP XR TS Decodability November 2014

    The measured value is an unsigned value.  If the measurement is
    unavailable, the value 0xFFFF MUST be reported.  NOTE 2 of the
    table in Section 5.2.1 of [ETSI] recommends using
    PMT_error_2_count.  Upon reception, if PMT_error_2_count is
    available (that is, other than 0xFFFF), then receivers MUST ignore
    PMT_error_count.
 PMT_error_2_count: 16 bits
    A count of the number of PMT2 errors that occurred in the above
    sequence number interval.  A PMT2_error occurs when (1) a packet
    containing table_id 0x02 (i.e., a PMT) does not occur at least
    every 0.5 seconds on each program_map_PID that is referred to in
    the PAT or (2) the Scrambling_control_field in the TS packet
    header is not 00 for all packets containing a table with table_id
    0x02 (i.e., a PMT) on each program_map_PID that is referred to in
    the PAT.  See Section 5.2.1 of [ETSI].
    The measured value is an unsigned value.  If the measurement is
    unavailable, then the value 0xFFFF MUST be reported.
 PID_error_count: 16 bits
    A count of the number of PID errors that occurred in the above
    sequence number interval.  A PID error occurs when no data stream
    is present corresponding to a given PID.  This may be caused by
    multiplexing or demultiplexing, then remultiplexing.  See
    Section 5.2.1 of [ETSI].
    The measured value is an unsigned value.  If the measurement is
    unavailable, then the value 0xFFFF MUST be reported.
 CRC_error_count: 16 bits
    A count of the number of CRC errors that occurred in the above
    sequence number interval.  A CRC_error occurs if data corruption
    occurred in any of the following tables -- CAT, PAT, PMT, Network
    Information Table (NIT), Event Information Table (EIT), Bouquet
    Association Table (BAT), Service Description Table (SDT), or Time
    Offset Table (TOT), as defined in Section 5.2.2 of [ETSI].
    The measured value is an unsigned value.  If the measurement is
    unavailable, then the value 0xFFFF MUST be reported.

Tong, et al. Standards Track [Page 7] RFC 7380 RTCP XR TS Decodability November 2014

 CAT_error_count: 16 bits
    A count of the number of CAT errors that occurred in the above
    sequence number interval.  A CAT_error occurs when (1) a packet
    with PID 0x0001 contains a table with a table_id other than 0x01
    (i.e., not a CAT) or (2) a packet does not contain a table with
    table_id = 0x01 (i.e., a CAT) when scrambling is employed (i.e.,
    the Scrambling_control_field is set as a value other than 00).
    See Section 5.2.2 of [ETSI].
    The measured value is an unsigned value.  If the measurement is
    unavailable, then the value 0xFFFF MUST be reported.
 Reserved: 16 bits
    These bits are reserved.  They MUST be set to zero by senders
    ignored by receivers (see Section 4.2 of [RFC6709]).

4. SDP Signaling

 [RFC3611] defines the use of the Session Description Protocol (SDP)
 [RFC4566] for signaling the use of RTCP XR blocks.  However, XR
 blocks MAY be used without prior signaling (see Section 5 of
 [RFC3611]).

4.1. SDP rtcp-xr-attrib Attribute Extension

 This session augments the SDP attribute "rtcp-xr" defined in
 Section 5.1 of [RFC3611] by providing an additional value of
 "xr-format" to signal the use of the report block defined in this
 document.  The ABNF [RFC5234] syntax is as follows:
 xr-format =/  xr-tpd-block
 xr-tpd-block = "ts-psi-decodability"

4.2. Offer/Answer Usage

 When SDP is used in Offer/Answer context, the SDP Offer/Answer usage
 defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters
 applies.  For detailed usage of Offer/Answer for unilateral
 parameters, refer to Section 5.2 of [RFC3611].

4.3. Usage Outside of Offer/Answer

 For usage outside of Offer/Answer, refer to Section 5.3 of [RFC3611].

Tong, et al. Standards Track [Page 8] RFC 7380 RTCP XR TS Decodability November 2014

5. IANA Considerations

 New report block types for RTCP XR are subject to IANA registration.
 For general guidelines on IANA allocations for RTCP XR, refer to
 Section 6.2 of [RFC3611].

5.1. New RTCP XR Block Type Value

 This document assigns the block type value 32 "MPEG2 Transport Stream
 PSI Decodability Statistics Metrics Block" in the "RTCP XR Block
 Type" subregistry of the IANA "RTP Control Protocol Extended Reports
 (RTCP XR) Block Type Registry".

5.2. New RTCP XR SDP Parameter

 This document also registers a new parameter "ts-psi-decodability" in
 the "RTCP XR SDP Parameters" subregistry of the "RTP Control Protocol
 Extended Reports (RTCP XR) Session Description Protocol (SDP)
 Parameters Registry".

5.3. Contact Information for Registrations

 The contact information for the registrations is:
 RAI Area Directors <rai-ads@tools.ietf.org>

6. Security Considerations

 This proposed RTCP XR block introduces no new security considerations
 beyond those described in [RFC3611] and [RFC6990].

7. References

7.1. Normative References

 [ETSI]     ETSI, "Digital Video Broadcasting (DVB); Measurement
            guidelines for DVB systems", ETSI TR 101 290, June 2014.
 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119, March 1997,
            <http://www.rfc-editor.org/info/rfc2119>.
 [RFC3550]  Schulzrinne, H., "RTP: A Transport Protocol for Real-Time
            Applications", RFC 3550, July 2003,
            <http://www.rfc-editor.org/info/rfc3550>.

Tong, et al. Standards Track [Page 9] RFC 7380 RTCP XR TS Decodability November 2014

 [RFC3611]  Friedman, T., Caceres, R., and A. Clark, "RTP Control
            Protocol Extended Reports (RTCP XR)", RFC 3611, November
            2003, <http://www.rfc-editor.org/info/rfc3611>.
 [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
            Description Protocol", RFC 4566, July 2006,
            <http://www.rfc-editor.org/info/rfc4566>.
 [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
            Specifications: ABNF", STD 68, RFC 5234, January 2008,
            <http://www.rfc-editor.org/info/rfc5234>.

7.2. Informative References

 [ISO-IEC.13818-1.2007]
            ISO/IEC, "Information technology - Generic coding of
            moving pictures and associated audio information - Part 1:
            Systems", ISO International Standard 13818-1, 2013.
 [RFC6390]  Clark, A. and B. Claise, "Guidelines for Considering New
            Performance Metric Development", BCP 170, RFC 6390,
            October 2011, <http://www.rfc-editor.org/info/rfc6390>.
 [RFC6709]  Carpenter, B., Aboba, B., and S. Cheshire, "Design
            Considerations for Protocol Extensions", RFC 6709,
            September 2012, <http://www.rfc-editor.org/info/rfc6709>.
 [RFC6792]  Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the
            RTP Monitoring Framework", RFC 6792, November 2012,
            <http://www.rfc-editor.org/info/rfc6792>.
 [RFC6990]  Wu, Q., "RTP Control Protocol (RTCP) Extended Report (XR)
            Block for MPEG2 Transport Stream (TS) Program Specific
            Information (PSI) Independent Decodability Statistics
            Metrics reporting", RFC 6990, May 2013,
            <http://www.rfc-editor.org/info/rfc6990>.

Tong, et al. Standards Track [Page 10] RFC 7380 RTCP XR TS Decodability November 2014

Authors' Addresses

 Jiangang Tong
 Shanghai Research Institute of China Telecom Corporation Limited
 No. 1835, South Pudong Road
 Shanghai  200122
 China
 EMail: tongjg@sttri.com.cn
 Claire Bi (editor)
 Shanghai Research Institure of China Telecom Corporation Limited
 No. 1835, South Pudong Road
 Shanghai  200122
 China
 EMail: bijy@sttri.com.cn
 Roni Even
 Huawei
 14 David Hamelech
 Tel Aviv  64953
 Israel
 EMail: roni.even@mail01.huawei.com
 Qin Wu (editor)
 Huawei
 101 Software Avenue, Yuhua District
 Nanjing, Jiangsu  210012
 China
 EMail: bill.wu@huawei.com
 Rachel Huang
 Huawei
 101 Software Avenue, Yuhua District
 Nanjing, Jiangsu  210012
 China
 EMail: rachel.huang@huawei.com

Tong, et al. Standards Track [Page 11]

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