1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0100008.2007(R2012) Defects Per Million (DPM) Metric for Transaction Services Such as VoIP As a leading technology and solutions development organization, ATIS brings together the top global ICT companies to advance the industrys most-pressing
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15、is taken with respect to whether use of an invention covered by patent rights will be required, and if any such use is required no position is taken regarding the validity of this claim or any patent rights in connection therewith. ATIS-0100008.2007(R2012), Defects Per Million (DPM) Metric for Trans
16、action Services Such as VoIP Is an American National Standard developed by the ATIS Network Performance, Reliability, and Quality of Service Committee (PRQC). Published by Alliance for Telecommunications Industry Solutions 1200 G Street, NW, Suite 500 Washington, DC 20005 Copyright 2012 by Alliance
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18、n the United States of America. ATIS-0100008.2007 American National Standard for Telecommunications DEFECTS PER MILLION (DPM) METRIC FOR TRANSACTION SERVICES SUCH AS VOIP Secretariat Alliance for Telecommunications Industry Solutions Approved May 22, 2007 American National Standards Institute, Inc.
19、Abstract This standard defines a metric that can gauge the ability of an IP network to deliver transaction services in an acceptable manner. Transactions such as Voice over IP (VoIP) calls are either successfully completed as required, or they are considered to be defects. The DPM metric is defined
20、as the ratio of all defective transactions to the total number of transactions attempted over a pre-determined period, normalized by a factor of one million. ATIS-0100008.2007 ii FOREWORD The information contained in this Foreword is not part of this American National Standard (ANS) and has not been
21、 processed in accordance with ANSIs requirements for an ANS. As such, this Foreword may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the Standard. The Alliance for Telecommunication In
22、dustry Solutions (ATIS) serves the public through improved understanding between carriers, customers, and manufacturers. The Network Performance, Reliability, and Quality of Service Committee (PRQC) - formerly T1A1 - develops and recommends standards, requirements, and technical reports related to t
23、he performance, reliability, and associated security aspects of communications networks, as well as the processing of voice, audio, data, image, and video signals, and their multimedia integration. PRQC also develops and recommends positions on, and foster consistency with, standards and related sub
24、jects under consideration in other North American and international standards bodies. ANSI guidelines specify two categories of requirements: mandatory and recommendation. The mandatory requirements are designated by the word shall and recommendations by the word should. Where both a mandatory requi
25、rement and a recommendation are specified for the same criterion, the recommendation represents a goal currently identifiable as having distinct compatibility or performance advantages. Suggestions for improvement of this document are welcome. They should be sent to the Alliance for Telecommunicatio
26、ns Industry Solutions, PRQC Secretariat, 1200 G Street NW, Suite 500, Washington, DC 20005. At the time it approved this document, PRQC, which is responsible for the development of this Technical Report (TR), had the following members: M. Neibert, PRQC Chair N. Seitz, PRQC Vice-Chair C. Underkoffler
27、, ATIS Chief Editor P. Tarapore, PRQC Technical Editor Organization Represented Name of Representative Alcatel USA Inc. Ken Biholar AT&T Percy Tarapore Charles A. Dvorak (Alt) Avici Systems Esmeralda Swartz BellSouth Telecommunications Archie McCain Cingular Wireless LLC Don Zelmer Marc Grant (Alt)
28、Department of Defense Chris Fitzgerald Embarq Corporation Carl M. Coopage John M. Heinz (Alt) Ericsson Incorporated Mustafa Kocaturk Susan Sabater-Maroto(Alt) ETRI Tae-Soo Chung Sung-Soo Kang (Alt) Intelsat Mark Neibert Lucent Technologies Stuart O. Goldman National Communications Systems An Nguyen
29、Carol-Lyn Taylor (Alt) Organization Represented Name of Representative National Telecom & Info Admin - NTIA Neal B. Seitz Arthur Webster (Alt) Nortel Joseph A. Zebarth Qwest Steve Showell Michael Fargano (Alt) Siemens Communications Inc. Suhas S. Gandhi David E. Francisco (Alt) Sprint Nextel Mark L.
30、 Jones Telcordia Technologies Spilios Makris Cliff Halevi (Alt) Tellabs Operations, Inc. William A. Walker Kevin Stodola (Alt) Verisign, Inc. Anthony M. Rutkowski Verizon Communications John Colombo Greg Cermak (Alt) The Quality of Service (QoS) Working Group, which was responsible for the developme
31、nt of this document, had the following members: N. Seitz, QoS Chair P. Tarapore, QoS Technical Editor Active Participants: J. Bennett M. Dolly C. Dvorak R. Holley P. Kimbrough S. Makris A. McCain M. Niebert A. Nguyen R. Oppenheim A. Remash N. Seitz A. Webster ATIS-0100008.2007 iii TABLE OF CONTENTS
32、1 SCOPE & PURPOSE .1 2 NORMATIVE REFERENCES .1 3 DEFINITIONS1 4 ACRONYMS & ABBREVIATIONS 2 5 INTRODUCTION AND RATIONALE2 6 ILLUSTRATIVE EXAMPLE DEFECTS PER MILLION METRIC FOR VOIP .3 6.1 DEFINITION OF VOIP DPM METRIC .4 6.2 VOIP DPM MEASUREMENT IMPLEMENTATION ISSUES 5 7 BIBLIOGRAPHY.6 TABLE OF FIGUR
33、ES FIGURE 1 - GENERIC VOIP NETWORK INTERCONNECTION ARCHITECTURE4 TABLE OF TABLES TABLE 1 - FAILURE RULES .5 AMERICAN NATIONAL STANDARD ATIS-0100008.2007 American National Standard for Telecommunications Defects per Million (DPM) Metric for Transaction-Based Services such as VoIP 1 1 SCOPE & PURPOSE
34、This document provides definitions for a metric that can be used to gauge the ability of an IP network to deliver transaction services in an acceptable manner. A transaction is defined as an IP network session involving a sequence of related information exchanges and processing operations designed t
35、o accomplish a specified service function. Examples of transactions include Voice over IP (VoIP) phone calls, web page access, file downloads, and or e-mail services. Transactions are either successfully completed by an IP network or encounter conditions that prohibit their successful completion. Su
36、ch failed transactions are called defects. The proposed metric defines the ratio of “defective” transactions to the total number of attempted transactions and normalizes them by a factor of one million Defects per Million (DPM). As IP networks evolve, transaction-based services may span several netw
37、ork domains. For example, a VoIP call may originate over an IP network and complete over the Public Switched Telephone Network (PSTN). The scope for estimating the DPM metric is restricted to the traversal over the IP network domain1. The scope of this document is also restricted to the definition o
38、f whether a transaction is “successfully” completed over the IP network portion or not. Thus, transaction quality issues such as degraded VoIP call quality caused by delay and jitter are not considered for the moment. A properly completed transaction is considered to be “successful” irrespective of
39、the transmission quality. This document provides an illustrative example on the use of the DPM metric for VoIP services. Examples on DPM usage for other transaction services over IP networks (e.g., Virtual Private Network services) will be discussed in future documents. 2 NORMATIVE REFERENCES The fo
40、llowing standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standa
41、rd are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. None identified in this document. 3 DEFINITIONS 3.1 Defects per Million: This metric is defined as the ratio of all defective transactions to the total number of transaction attemp
42、ts in millions, over a fixed time interval (e.g., one month, one year). 1This limitation has been recognized in previous discussions in PRQC, and will be addressed in future documents. ATIS-0100008.2007 2 3.2 Transaction: An IP network session involving a sequence of related information exchanges an
43、d processing operations designed to accomplish a specified service function. 4 ACRONYMS & ABBREVIATIONS CAI Customer Affecting Incident CDR(s) Call Detail Record(s) DPM Defects per Million IP Internet Protocol ITU-T International Telecommunications Union-Telecommunication NER Network Effectiveness R
44、atio PRQC Performance Reliability and Quality of Service Committee PSTN Public Switched Telephone Network SLA Service Level Agreement VoIP Voice over IP VPN Virtual Private Network 5 INTRODUCTION AND RATIONALE Current network trends indicate significant increases in traffic volume for services of di
45、fferent types over IP networks. Traffic types include real-time services (e.g., VoIP and video), data services, “Enterprise Customer” services over “Virtual Private Networks” (VPN), IPTV services, as well as traditional Internet services such as e-mail and Web browsing. Estimating the ability of an
46、IP network to deliver acceptable transaction-based services can be complicated by significant operational constraints. IP networks in their current mode of operation are essentially “connectionless”. Thus, packets representing any given “session” may be routed over different physical routes over the
47、 IP network, so long as the packet reassembly at the IP terminating end point is done in the correct order. It is however critical to note that services such as VoIP can be considered as transactions and it is possible to track the status of all such transactions even in IP network elements. A trans
48、action can be characterized as a success if all of the following steps are accomplished: Network Access: The user gains access to an IP network. Network Traversal: The network establishes an end-to-end IP flow. Termination: Upon completion, the IP network releases the transaction thus terminating th
49、e session. A transaction is defined to be a failure or defect if any of the above steps is not accomplished. A defective transaction is defined to be either a blocked transaction or a cutoff transaction as follows: A blocked transaction is a transaction that is unable to gain network access or network traversal due to network failure or congestion. ATIS-0100008.2007 3 A cutoff transaction is a transaction that achieves network access and traversal, but is prematurely terminated due to some network failure condition. Note that a transaction cut off by an e
