1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU 1.366.2 (1 1 /2000) SERIES I: INTEGRATED SERVICES DIGITAL NETWORK Overall network aspects and functions - Protocol layer req u i remen ts AAL type 2 service specific convergence sublayer for narrow-band servi
2、ces ITU-T Recommendation 1.366.2 (Formerly CCITT Recommendation) ITU-T I-SERIES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK GENERAL, STRUCTURE Terminology Description of ISDNs General modelling methods Telecommunication network and service attributes General description of asynchronous trans
3、fer mode Scope General aspects of services in ISDN Common aspects of services in the ISDN Bearer services supported by an ISDN Teleservices supported by an ISDN Supplementary services in ISDN Network functional principles Reference models Numbering, addressing and routing Connection types SERVICE CA
4、PABILITIES OVERALL NETWORK ASPECTS AND FUNCTIONS 1.110-1.119 1.120-1.129 I. 130-1.139 I. 140-1.149 1.150-1.199 1.200-1.209 1.210-1.219 1.220-1.229 1.230-1.239 1.240-1.249 1.250-1.299 1.3 10-1.3 19 1.320-1.329 1.330-1.339 1.340-1.349 Performance objectives 1.350-1.359 General network requirements and
5、 functions 1.370-1.399 ISDN USER-NETWORK INTERFACES Application of I-series Recommendations to ISDN user-network interfaces Layer 1 Recommendations Layer 2 Recommendations Layer 3 Recommendations Multiplexing, rate adaption and support of existing interfaces Aspects of ISDN affecting terminal requir
6、ements INTERNETWORK INTERFACES MAINTENANCE PRINCIPLES B-ISDN EQUIPMENT ASPECTS ATM equipment Transport functions Management of ATM equipment Multiplexing aspects 1.420-1.429 1.430-1.439 1.440-1.449 1.450-1.459 1.460-1.469 1.470-1.499 1.500-1.599 1.600-1.699 1.730-1.739 1.740-1.749 1.750-1.759 1.760-
7、1.769 For further details, please rer to the list of ITD-T Recommendations. ITU-T Recommendation 1.366.2 AAL type 2 service specific convergence sublayer for narrow-band services Summary This Recommendation defines a Service Specific Convergence Sublayer that operates above the Common Part Sublayer
8、of an AAL type 2 connection. The purpose of the SSCS is to convey narrow-band channels consisting of voice, voiceband data, or circuit mode data. The SSCS specifies packet formats and procedures to encode the different information streams for bandwidth-efficient transport by AAL type 2. It accommoda
9、tes known techniques of low rate audio encoding, silence compression, and facsimile demodulatiodremodulation. It makes provision for in-band signalling of narrow-band calls and for control of the SSCS operating state. The SSCS anticipates that multiplexing in the Common Part Sublayer will be used to
10、 carry multiple narrow-band channels over individual ATM connections. Additional details needed to configure and manage trunk groups or access configurations, however, are beyond the scope of this Recommendation. The focus is on normative aspects of SSCS coding and behaviour within a single AAL type
11、 2 connection. Source ITU-T Recommendation 1.366.2 was revised by ITU-T Study Group 13 (2001-2004) and approved under the WTSA Resolution 1 procedure on 24 November 2000. ITU-T 1.366.2 (11/2000) 1 FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in th
12、e field of telecommunications. The ITU Telecommunication Standardization Sector (U-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 a worldwide basis. The
13、 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 U-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
14、In some areas of information technology which fall within U-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recog
15、nized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. U takes no position concerning the evidence, validity or applicability of claimed Intel
16、lectual Property Rights, whether asserted by U members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, U had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However
17、, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. o mu 2001 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, includi
18、ng photocopying and microfilm, without permission in writing from ITU. 11 ITU-T 1.366.2 (11/2000) CONTENTS 1 2 2.1 2.2 3 4 6 7 7.1 7.2 8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 9 9.1 9.2 10 10.1 10.2 11 11.1 11.2 Scope . References . Normative references Bibliography Definitions Abbreviations
19、Conventions Reference model . Functional description . Transmitter functions Receiver functions Services provided Audio service Circuit mode dah service Frame mode data service Dialled digits service . Channel-associated signalling service Facsimile demodulatiodremodulation service . Alarms service
20、State control service Rate control service . Change SSCS operation service Loopback service Delay variation in user processing Means to achieve isochrony Delay variation below the SSCS sublayer Packet format types . Type 1 -Unprotected Type 3 . Fully protected . Common facilities for type 3 packets
21、. Relative event timing Triple redundancy and refresh ITU-T 1.366.2 (11/2000) Page 1 3 5 5 6 9 11 12 13 13 14 14 15 16 16 17 17 17 17 18 19 19 19 21 21 21 . 111 12 13 13.1 13.2 13.3 13.4 14 14.1 14.2 14.3 14.4 15 16 17 17.1 17.2 17.3 17.4 17.5 17.6 17.7 18 UUI codepoint assignments Encoding format p
22、rofiles The function of a profile . Relationship of service data unit and sequence number interval Examples of profile stnichire Mandatory profile support Sequence numbering . Basic principles . Incrementing during silence Change of sequence number interval Embedding in UUI codepoints Circuit mode d
23、ata Frame mode data . Facsimile demodulatiodremodulation . Functional requirements 17.2.1 Protocol analysis 17.2.2 Waveform analysis Optional support of non-standard facilities . Timing requirements . Starting and stopping facsimile demodulation Facsimile demodulation packets . Two methods of analys
24、is Transparency for T.30 data . SSCS parameters of operation Annex A . Specification of audio encoding formats . Annex B . Encoding format for audio algorithm G.7 1 1 B.2 Encoding data unit Annex C . Encoding format for audio algorithm G.722 . C.2 Encoding data unit Annex D - Encoding format for aud
25、io algorithm G.723.1 D.2 Encoding data unit B.l General C.l General D.l General iv ITU-T 1.366.2 (11/2OOO) Page 22 22 22 23 24 25 25 25 26 26 26 27 27 28 28 28 28 28 29 29 29 30 30 30 32 32 32 33 34 34 34 35 35 35 D.3 Silence insertion descriptor . Page 36 Annex E . Encoding format for audio algorit
26、hm G.726 E.l General E.2 Encoding data unit Annex F . Encoding format for audio algorithm G.727 F.2 Encoding data unit F.l General Annex G . Encoding format for audio algorithm G.728 . G.l General G.2 Encoding data unit Annex H . Encoding format for audio algorithm G.729 . H.2 Encoding data unit H.3
27、 Silence insertion descriptor . G.729-6.4 encoding data unit G.729- 12 encoding data unit . H.l General H.4 H.5 Annex I . Encoding format for generic silence insertion descriptor . I . 1 General 1.2 Packet format 1.3 Procedures . Annex J . Encoding format for circuit mode data at N*64 kbit/s . J . 1
28、 Packet format Annex K . Packet format and procedures for dialled digits K.l General K.2 Packet format K.3 Transmitter procedures . K.4 Receiver procedures Annex L - Packet format and procedures for channel-associated signalling bits . L.l General L.2 Packet format L.3 Transmitter procedures . L.4 R
29、eceiver procedures Annex M - Packet format and procedures for facsimile demodulation . M . 1 Facsimile demodulation control concepts . ITU-T 1.366.2 (11/2OOO) 36 36 37 38 38 38 39 39 39 40 40 40 41 41 42 43 43 43 43 44 44 45 45 46 48 48 49 49 49 50 50 50 50 V M.2 M.3 M . 1.1 Message types M . 1.2 M.
30、1.3 T.30 Data . M . 1.4 Common facilities M.1.5 Time stamps . M . 1.6 M . 1.7 Modulation control messages . Sequence numbers . Robustness against packet loss Facsimile demodulation control packets . M.2.1 T.30-Preamble . M.2.2 EPT M.2.3 Training . M.2.4 Fax Idle . M.2.5 T.30 Data - - Facsimile image
31、 data packets Annex N . Packet format and procedures for OAM (alarms and loopback) . N.l General N.2 Packet format N.2.1 Alarm Packet format N.2.2 Loopback Packet format N.3 Procedures . N.3.1 Alarm procedures . N.3.2 Loopback procedures . Annex O - Packet format and procedures for user state contro
32、l 0.1 General 0.2 Packet format 0.3 Procedures . Annex P - Predefined encoding format profiles Annex Q - Encoding format for audio algorithm AMR Q.1 General 4.2 Encoding Data Unit . 4.3 Silence Descriptor . Annex R - Packet formats and procedures for rate control . R.l General R.2 Packet format R.3
33、Transmitter procedures . R.4 Receiver procedures vi ITU-T 1.366.2 (11/20OO) Page 50 51 51 51 51 51 52 52 52 52 53 54 54 56 57 57 57 58 58 58 58 59 60 60 60 62 63 68 68 68 82 83 83 83 83 83 Page Annex S . Packet formats and Procedures for synchronization of change in SSCS S.l General S.2 Packet forma
34、t S.3 Transmitter procedures . S.4 Receiver procedures operation . Appendix I . AAL Type 1 interworking between N-ISDN and B-ISDN 1.3 Informative references Appendix II . Simple derivation of the modulus for sequence numbering . II . 1 Packet flow timing notation and relationships 11.2 Simple deriva
35、tion of the modulus . Appendix III . Example facsimile demodulation scenarios III . 1 Typical facsimile demodulation scenario . Normal completion III.2 III.3 Fallback to voiceband data . NSS not supported . Fallback to voiceband data . demodulation failure Appendix IV . Example facsimile demodulatio
36、n V . 17 training Appendix V - Protocol implementation conformance statement (PICS) proforma V . 1 Introduction . V.l.l Scope . V . 1.2 Normative references . V . 1.3 Abbreviations . V . 1.4 Conformance statement . V.2 PICS proforma V.2.1 V.2.2 V.2.3 V.2.4 Identification ofthe PICS proforma corrigen
37、da Instructions for completing the PICS proforma . Global statement of conformance Identification of the implementation . Appendix VI . Use of this Recommendation for mobile applications 84 84 84 84 84 84 85 85 85 86 87 87 91 93 96 97 97 97 97 97 97 98 98 98 98 99 106 ITU-T 1.366.2 (11/2OOO) vii ITU
38、-T Recommendation 1.366.2 AAL type 2 service specific convergence sublayer for narrow-band services 1 Scope The SSCS specifies packet formats and procedures for the following kinds of information: - voice encodings; - silence insertion descriptors; - circuit mode digital information; - fi-ame mode d
39、ata units; - dialled digits (multifrequency tones); - channel associated signalling bits; - demodulated facsimile; - alarm indications; - user state control operations; - rate control; - - channel loopback. In general, if an application chooses to implement one or more of the information types, its
40、default option should be to adhere to the corresponding parts of this Recommendation. But the use of alternative packet formats and procedures, standard or proprietary, is not precluded. The SSCS is defined fi-om the point of view of one instance operating in a single AAL type 2 connection. Other AA
41、L type 2 connections routed over the same ATM connection may employ the same or different SSCS. Any coordination between events that occur on different AAL type 2 connections is outside the scope of this Recommendation. An instance of the SSCS is characterized by the parameters of operation summariz
42、ed in clause 18. Some are complex data structures, like the agreed profile of encoding formats in effect. Values of the parameters shall be agreed between the transmitter and the receiver SSCS to be the same for both directions of communication. It is outside the scope of this Recommendation to stat
43、e how an instance of the SSCS with specific parameter values should be selected for a particular AAL type 2 connection. NOTE - Some possibilities are: 1) 2) synchronization of change in SSCS operation; A configuration may be agreed in advance and imposed manually. The identity of the SSCS and its pa
44、rameters may be communicated through signalling Q.2630.1, Q.2630.21. 2 References This Recommendation does not define algorithms for encoding audio streams. It references existing algorithms and specifies how the bits that they output are conveyed within a packet structure. It also makes provision f
45、or multiple audio algorithms to be composed into an operational profile, so that the encoding can be varied rapidly among them during a call. ITU-T 1.366.2 (11/2000) 1 2.1 Normative references The following ITU-T Recommendations and other references contain provisions which, through reference in thi
46、s 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; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent
47、edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T G.704 (1998), Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44 736 kbith hierarchical levels. ITUT-T G.711 (1988), Pulse code modulati
48、on (PCM) of voice frequencies. ITU-T G.722 (1988), 7 WTz audio-coding within 64 kbith. ITU-T G.723.1 (1996), Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbith. ITU-T G.723.1 Annex A (1 996), Silence compression scheme. ITU-T G.726 (1990), 40, 32, 24, 16 kbith ada
49、ptive diferential pulse code modulation ITU-T G.727 (1990), 5, 4, 3- and 2-bitshample embedded adaptative diferential pulse code modulation (ADPCM). ITU-T G.728 (1992), Coding of speech at 16 kbith using low-delay code excited linear prediction. ITU-T G.728 Annex H (1999), Variable bit rate LD-CELP operation mainly for DCME at rates less than 16 kbith. ITU-T G.729 (1996), Coding of speech at 8 kbith using conjugate-structure algebraic-code- excited linear prediction (CS-ACELP). ITU-T G.729 Annex A (1996), Reduced complexity 8 kbith CS-ACELP speech codec. ITU-T G.729 Annex B (199
