1、 ATIS-0800011 QUALITY OF SERVICE METRICS AND MEASUREMENTS FOR PUBLIC SERVICES The Alliance for Telecommunication Industry Solutions (ATIS) is a technical planning and standards development organization that is committed to rapidly developing and promoting technical and operations standards for the c
2、ommunications and related information technologies industry worldwide using a pragmatic, flexible and open approach. Over 1,100 participants from more than 350 communications companies are active in ATIS 23 industry committees and its Incubator Solutions Program. Notice of Disclaimer 2. Closed Capti
3、oning and Content Advisories (CA); and 3. V-Chip Technology. Since 2000, the Federal Communications Commission (FCC) has required all U.S. television sets with screen sizes greater than 13 inches to provide a mechanism to screen content based on content advisories. The capability is generally referr
4、ed to as V-Chip Technology. 1.2 Goal The goal of this document is to define a base set of Quality of Service (QoS) metrics for regulatory services as completely as possible as defined per ATIS-0800002, IPTV Architecture Requirements 1. The Alliance for Telecommunications Industry Solutions (ATIS) IP
5、TV Interoperability Forum (IIF) recognizes that as the IPTV architecture is currently a work in progress, not all QoS metrics applicable for public service can be envisioned at this time. Additional QoS metrics may be added at a later time as more functional components of the architecture are define
6、d. 1.3 Purpose The purpose of this document is to provide the industry with a first set of well-defined public service QoS metrics that are deployable and immediately useful. 1.4 Scope and Assumptions The following characteristics identify the scope of this document: QoS metrics in ATIS-0800008, QoS
7、 Metrics for Linear Broadcast IPTV 3, contains all currently recommended QoS metrics. Scope and assumptions from QoS metrics in 3 are all applicable. Measurement methodologies are for further study. This document assumes the use of a MPEG-2 TS ISO/IEC 13818-1 Information technology Generic coding of
8、 moving pictures and associated audio information: Systems C (2000) 10 stream format. ATIS-0800011 2 2 NORMATIVE REFERENCES The following standards contain provisions which, through reference in this text, constitute provisions of this ATIS Standard. At the time of publication, the editions indicate
9、d were valid. All standards are subject to revision, and parties to agreements based on this ATIS Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. 2.1 ATIS11 ATIS-0800002, IPTV Architecture Requirements, ATIS-IIF, May 2006.
10、 2 ATIS-0800004, A Framework for QoS Metrics and Measurements supporting IPTV Services, ATIS-IIF, October 2006. 3 ATIS-0800008, A QoS Metrics for Linear Broadcast IPTV, ATIS-IIF, August 2007. 4 ATIS-0800010, Emergency Alert Service Provisioning Specifications, ATIS-IIF. Projected publication date is
11、 February 2008. 2.2 FCC 5 FCC, 47 U.S.C. 151, 154 (i) and (o), 303(r), 544(g), and 606, Electronic Code of Federal Regulations Title 47: Telecommunication, Part 11- Emergency Alert System (EAS), 59 FR 67092, Dec. 28, 1994. 2.3 CEA26 CEA-708-C, Digital Television (DTV) Closed Captioning, 2006. 7 CEA-
12、766-C, U.S. Region Rating Table (RRT) and Content Advisory Descriptor for Transport of Content Advisory Information Using ATSC A/65 Program and System Information Protocol (PSIP), 2006. 2.4 ATSC38 A/65, Revision C, Program and System Information Protocol for Terrestrial Broadcast and Cable (2007). 9
13、 A/53, Part 4, Digital Television Standard Part 4 MPEG-2 Video System Characteristics (2007). 2.5 ISO/IEC410 ISO/IEC 13818-1, Information technology Generic coding of moving pictures and associated audio information: Systems C (2000). 1These documents are available from the Alliance for Telecommunic
14、ations Industry Solutions, 1200 G Street N.W., Suite 500, Washington, DC 20005. 2These documents are available from the Consumer Electronics Association. 3These documents are available from the Advanced Television Systems Committee. 4This document is available from the International Organization for
15、 Standardization. ATIS-0800011 3 2.6 OASIS511 OASIS Standard 200402, Common Alerting Protocol (CAP), 2004. 2.7 ARIB612 ARIB STD-B24, Data Coding and Transmission Specifications for Digital Broadcasting, May 2006. 3 DEFINITIONS, ACRONYMS, therefore, ATSC terrestrial broadcast standards state that the
16、 transmission of the U.S. RRT 0x01 is optional. In PSIP 8, the ATSC defines the bit stream syntax for the Content Advisory Descriptor. Like the captioning service, the descriptor for Content Advisory is found in the PMT when content advisory data is present. Since 2000, the FCC has required all U.S.
17、 television sets with screen sizes greater than 13 inches to provide a mechanism to screen content based on content advisories. The behavior of the ITF in reaction to this signaling may be established in the FCC rules and is outside the scope of ATIS standards. ATIS-0800011 6 5 USE CASES As identifi
18、ed in ATIS-0800004, A Framework for QoS Metrics and Measurements supporting IPTV Services 2, use cases are used here in the analysis of QoS metrics for Emergency Alert Systems, Closed Captioning and Content Advisories, and V-Chip Technology to help define the scope of the service definition. From a
19、service perspective, the following user-initiated actions can be observed in the Linear/Broadcast IPTV service: 1. An Emergency Alert System activation. 2. User selects Closed Captioning on the ITF. 3. User selects a channel with Content Advisory (CA). 5.1 Emergency Alert System The ITF will receive
20、 a notification to do mandatory channel change to an emergency IPTV linear broadcast channel. The ITF will record the number of notifications received to ensure the broadcast is delivered effectively. The method of notifications related to emergency channels is out of scope of this document and is c
21、overed in ATIS-0800010, Emergency Alert Service Provisioning Specifications 4. 5.2 Closed Captioning Closed Captioning is present as part of an MPEG-2 TS and 3 has metrics that would notice the Closed Captioning stream is missing. No additional metrics are recommended at this time. Metrics defined i
22、n 3 support these use cases. 5.3 Content Advisories (CA) and V-Chip Technology Content advisories can be present as part of an MPEG-2 TS and 3 does not have specific metrics to signal the presence of content advisory descriptors. A metric to indicate the presence of this descriptor is recommended in
23、 clause 7.3 below. 6 MEASUREMENT MODEL 6.1 Emergency Alert System A description of this system and its architecture can be found in 4. Emergency services consist of three types: text only, audio plus text, and forced acquisition. These services are expected to be delivered out-of-band using the Comm
24、on Alerting Protocol (CAP), OASIS Standard 200402 11, implemented with XML. EAS messages can be inserted into the network at many places, depending on the nature of the emergency. FCC requirements are for national, regional, state, and local insertion of EAS messages into the network. Quality of Ser
25、vice for emergency services is specified in this document as a presence/no presence. For this reason, it is recommended that measurement be taken at each ITF and other critical points in the network as a counter of the number of times the service is activated in the measurement interval. ATIS-080001
26、1 7 6.2 Closed Captioning Proposed Closed Captioning standards are provided in 6 for digital TV. Digital Closed Captions are described in ARIB-STD-B24 12. Closed Caption Content is transmitted in the MPEG-2 TS in packet form. The Caption Distribution Packet (CDP) is defined in CEA-708-C 6. Captions
27、are distributed on dedicated Program Identifiers (PIDs). ATSC defines the Caption Service in 8 and provides a descriptor, tag, and location in the PMT or EIT of the IPTV signal metadata encoded using PSIP. As the CDPs are delivered as part of the media stream, packet loss can occur, and the CDPs can
28、 become out of synchronization with their associated video stream. Some of the metrics described in 3 for measuring packet loss and audio video synchronization apply here. A Mean Opinion Score (MOS) is not recommended for Closed Captioning. 6.3 Content Advisories and V-Chip Technology The PSIP RRT,
29、defined in 7, is the key to enabling the V-Chip Technology in an ITF or a display device. The V-Chip Technology is a proprietary implementation to block unwanted content, owned by Tim Collings and the University of British Columbia. It has been mandated by the FCC as the means to block the display o
30、f television content based on its rating. The ATSC defines the Content Advisory Service in 8 and provides a descriptor, tag, and location in the PMT or EIT of the IPTV signal metadata. 7 METRICS/FAULT CODES 7.1 Emergency Alert System The following metric is recommended by ATIS, but not currently man
31、dated by U.S. federal regulations. Table 1: EAS Metric No. Name Definition Units Type Measurement Points Comments (incl. justification for/ usefulness of the metric) 1 Number of emergency events Total number of times the EAS system is activated during a measurement interval. Counter Unsigned 16 bit
32、integer Transmission measurement points: D, E, and F This metric validates the presence of the EAS signal. 7.2 Closed Captioning Refer to 3, Table 2: Recommended IPTV Metrics, for PMT and EIT metrics where the Closed Captioning is typically carried. ATIS-0800011 8 7.3 Content Advisories and V-Chip T
33、echnology Table 2: CA Metric No. Name Definition Units Type Measurement Points Comments (incl. justification for/ usefulness of the metric) 1 Presence of content advisory stream A non-empty descriptor in the PMT or EIT as in 8 in a measurement interval. Count Unsigned 16 bit integer B, B1, C, C1, D,D1,E, F This metric indicates the presence of the content advisory signal, not its value.
