1、 International Telecommunication Union ITU-T Q.3911TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2010) SERIES Q: SWITCHING AND SIGNALLING Signalling requirements and protocols for the NGN Testing for NGN networks Parameters for monitoring voice services in NGN Recommendation ITU-T Q.3911 ITU-T
2、 Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS
3、 OF SIGNALLING SYSTEMS No. 4, 5, 6, R1 AND R2 Q.120Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.10
4、99 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 SIGNALLING REQUIREMENTS
5、AND PROTOCOLS FOR THE NGN Q.3000Q.3999 General Q.3000Q.3029 Network signalling and control functional architecture Q.3030Q.3099 Network data organization within the NGN Q.3100Q.3129 Bearer control signalling Q.3130Q.3179 Signalling and control requirements and protocols to support attachment in NGN
6、environments Q.3200Q.3249 Resource control protocols Q.3300Q.3369 Service and session control protocols Q.3400Q.3499 Service and session control protocols supplementary services Q.3600Q.3649 NGN applications Q.3700Q.3849 Testing for NGN networks Q.3900Q.3999For further details, please refer to the l
7、ist of ITU-T Recommendations. Rec. ITU-T Q.3911 (06/2010) i Recommendation ITU-T Q.3911 Parameters for monitoring voice services in NGN Summary Recommendation ITU-T Q.3911 defines the set of monitoring parameters that will impact the quality of voice services in NGN. These parameters are generated b
8、y network elements, such as terminal elements, connection elements, transmission elements, etc. The definitions provided here are dependent on NGN, which uses the session initiation protocol (SIP) as call control protocol. How to monitor these parameters is out of the scope of this Recommendation. H
9、istory Edition Recommendation Approval Study Group 1.0 ITU-T Q.3911 2010-06-13 11 Keywords Monitoring parameters, NGN, voice services. ii Rec. ITU-T Q.3911 (06/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications,
10、information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on
11、a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid dow
12、n in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication
13、administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory
14、provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attent
15、ion to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others
16、outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent th
17、e latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T Q.3911 (06/2010) iii
18、 CONTENTS Page 1 Scope 1 2 References. 1 3 Abbreviations 2 4 Definitions 2 5 Conventions 2 6 Measurement metrics 2 6.1 Active measurement . 2 6.2 Passive measurement 2 7 Monitoring parameters 2 7.1 Registration . 2 7.2 Call establishment 3 7.3 Quality of voice service 5 7.4 Codecs 6 7.5 Call complet
19、ion 8 Bibliography. 10 Rec. ITU-T Q.3911 (06/2010) 1 Recommendation ITU-T Q.3911 Parameters for monitoring voice services in NGN 1 Scope This Recommendation defines the set of parameters that will impact the quality of voice services in NGN. These parameters are generated by network elements, such a
20、s terminal elements, connection elements, transmission elements, etc. The definitions provided here are dependent on NGN, which uses SIP as call control protocol. How to monitor these parameters is out of the scope of this recommendation. 2 References The following ITU-T Recommendations and other re
21、ferences contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to i
22、nvestigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The references to a document within this Recommendation do not give it, as a stand-alone document, the
23、status of a Recommendation. ITU-T G.711 Recommendation ITU-T G.711 (1988), Pulse code modulation (PCM) of voice frequencies. ITU-T G.722 Recommendation ITU-T G.722 (1988), 7 kHz audio-coding within 64 kbit/s. ITU-T G.722.2 Recommendation ITU-T G.722.2 (2003), Wideband coding of speech at around 16 k
24、bit/s using Adaptive Multi-Rate Wideband (AMR-WB). ITU-T G.729 Recommendation ITU-T G.729 (2007), Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear prediction (CS-ACELP). ITU-T G.729.1 Recommendation ITU-T G.729.1 (2006), G.729-based embedded variable bit-rate code
25、r: An 8-32 kbit/s scalable wideband coder bitstream interoperable with G.729. ITU-T P.564 Recommendation ITU-T P.564 (2007), Conformance testing for voice over IP transmission quality assessment models. ITU-T P.800 Recommendation ITU-T P.800 (1996), Methods for subjective determination of transmissi
26、on quality. ITU-T P.800.1 Recommendation ITU-T P.800.1 (2006), Mean Opinion Score (MOS) terminology. ITU-T P.862 Recommendation ITU-T P.862 (2001), Perceptual evaluation of speech quality (PESQ): An objective method for end-to-end speech quality assessment of narrow-band telephone networks and speec
27、h codecs. 3GPP TS 26.071 3GPP TS 26.071 V6.0.0 (2004), Mandatory speech CODEC speech processing functions; AMR speech Codec; General description (Release 6). TIA-127-C TIA-127-C (2007), Enhanced Variable Rate Codec, Speech Service Options 3, 68, and 70 for Wideband Spread Spectrum Digital Systems. 2
28、 Rec. ITU-T Q.3911 (06/2010) 3 Abbreviations This Recommendation uses the following abbreviations and acronyms: IP Internet Protocol MOS Mean Opinion Score NGN Next Generation Networks PESQ Perceptual Evaluation of Speech Quality RTCP Real-time Transfer Control Protocol RTP Real-time Transfer Protoc
29、ol SCTP Session Control Transfer Protocol SIP Session Initiation Protocol UAC User Agent Client UDP User Datagram Protocol VoIP Voice over Internet Protocol 4 Definitions None. 5 Conventions None. 6 Measurement metrics 6.1 Active measurement Active measurements are used to obtain the value of measur
30、ement parameters by injecting a test stream or signals into the network. In this case, the test stream or signals are sent from one endpoint of the network, and received by the remote answering machine located at another endpoint. The analysis of the measurement parameters value can help to determin
31、e the performance or behaviour of the system. 6.2 Passive measurement In the case of passive measurements, a sniffer is used to detect call control signalling and VoIP flows, obtain the call leg RTP/RTCP, and then capture the statistics generated by the end-user. The sniffer can be deployed near the
32、 “gateway“ or equipped in the end-user. The hybrid usage of the two measurement metrics is usually preferred. 7 Monitoring parameters The following gives the most probable failure or poor performance reasons. In some cases, other reasons might apply. The comparison of several measurements might give
33、 additional information. 7.1 Registration This clause introduces the monitoring parameters for the registration phase in voice services, such as successful register rate, register delay, failed register rate, etc. The parameters are based on end-to-end measurements. Rec. ITU-T Q.3911 (06/2010) 3 7.1
34、.1 Successful register rate Successful register rate is defined as the rate of successful registration attempts in the voice service. This parameter can evaluate the performance and quality of voice service during the registration phase. Successful register rate is measured at the element node in th
35、e SIP link, for example, at the UAC. The parameter is calculated by monitoring the element node for a predefined time interval, e.g., 30 minutes. The output value of this parameter is numerical and should be reported as a percentage. The successful register rate is calculated using the following for
36、mula: Successful register rate = %100RnRnsucRn is the total number of REGISTER messages that are received and sent in the monitoring interval time, such as 30 minutes. Rnsucis the total number of successful and completed registrations, for example, the node receives or sends 200 OK responses. 7.1.2
37、Register delay Register delay is defined as the average time from the start of registration to the successful completion of registration in the voice service. This parameter is measured at the element node in the SIP link, for example, at the UAC. The parameter is averaged over a predefined time int
38、erval, e.g., 30 minutes. The output value of this parameter is numerical and should be stated in units of milliseconds. The register delay parameter is calculated using the following formula: Register delay = RnRtRttniii=1)(Rtiis the time when the ith registrations REGISTER Request message starts to
39、 be sent by the originating node. Rttiis the time when the ith registrations final Response, e.g., 200 OK, is completely received by the originating node. Rn is the total number of successful and completed registrations in the monitoring interval, such as 30 minutes. 7.1.3 Failed register rate Faile
40、d register rate is defined as the rate of failed registration attempts in the voice service. Failed register rate can evaluate the performance of the voice service in the network and indicates the inability of the network elements. For example, it may indicate a registrar has become overloaded and i
41、s unable to respond to the request. This parameter is measured at the element node in the SIP link, for example, at the UAC. The parameter is calculated by monitoring the element node for a predefined time interval, e.g., 30 minutes. The output value of this parameter is numerical and should be repo
42、rted as a percentage. The failed register rate parameter is calculated using the following formula: Failed register rate = %100RnRnfailedRn is the total number of REGISTER messages that are received and sent in the monitoring interval time, such as 30 minutes. Rnfailedis the total number of failed r
43、egistrations; for example, the node receives or sends message 401 as a response to REGISTER messages. 7.2 Call establishment This clause provides the monitoring parameters for the call establishment phases in the voice service, such as successful call establishment rate, pre-release rate, “route una
44、vailable“ rate, etc. The parameters are based on the end-to-end communication mode. 4 Rec. ITU-T Q.3911 (06/2010) 7.2.1 Successful call establishment rate Successful call establishment rate is defined as the rate of the successful call attempts in the voice service. This parameter can evaluate the p
45、erformance and quality of the voice service during the call establishment phase. Successful call establishment rate is measured at the element node in the SIP link, for example, the UAC or terminals. The parameter is calculated by monitoring the node for a predefined time interval, e.g., 30 minutes.
46、 The output value of this parameter is numerical and should be reported as a percentage. The parameter is calculated using the following formula: Successful call establishment rate = %100CnCnsucCn is the total number of INVITE messages that are received and sent by the node in the monitoring interva
47、l time, such as 30 minutes. Cnsucis the number of successful and completed call establishment, for example, 200 OK responses for the INVITE requests received or sent. 7.2.2 Pre-release rate Pre-release means that the CANCEL request is received or sent before the call is established. The pre-release
48、rate can evaluate the performance of the voice service and indicates the inability of the network. The parameter is measured at the UAC or end-users terminals. The parameter is calculated by monitoring the node for a predefined time interval, e.g., 30 minutes. The output value of this parameter is n
49、umerical and should be reported as a percentage. The parameter is calculated using the following formula: Pre-release rate = %100CnCnprereCn is the total number of INVITE messages that are received and sent by the node in the monitoring interval time, such as 30 minutes. Cnprereis the number of CANCEL messages that are received and sent before the ACK messages for the final 200 OK responses. 7.2.3 Failed call establishment rate Failed call establishment rate is defined as the rate at which failure indication responses
