1、INTERNATIONAL TELECOMMUNICATION UNIONITU-TQ.931TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU(05/98)SERIES Q: SWITCHING AND SIGNALLINGDigital subscriber Signalling System No. 1 Network layerISDN user-network interface layer 3specification for basic call controlITU-T Recommendation Q.931(Previously CC
2、ITT Recommendation)ITU-T Q-SERIES RECOMMENDATIONSSWITCHING AND SIGNALLINGFor further details, please refer to ITU-T List of Recommendations.SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN T
3、HE ISDN Q.60Q.99CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 Q.120Q.249SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399SPECIFICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499DIGITAL EXCHANGE
4、S Q.500Q.599INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.849DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999General Q.850Q.919Data link layer Q.920Q.929Network layer Q.930Q.939User-network management Q.940Q.949Stage 3 description for supplementar
5、y services using DSS 1 Q.950Q.999PUBLIC LAND MOBILE NETWORK Q.1000Q.1099INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199INTELLIGENT NETWORK Q.1200Q.1999BROADBAND ISDN Q.2000Q.2999Recommendation Q.931 (05/98) iITU-T RECOMMENDATION Q.931ISDN USER-NETWORK INTERFACE LAYER 3 SPECIFICATIONFOR BASIC
6、 CALL CONTROLSummaryThis Recommendation specifies the procedures for the establishing, maintaining and clearing ofnetwork connections at the ISDN user-network interface. These procedures are defined in terms ofmessages exchanged over the D-channel of basic and primary rate interface structures. The
7、functionsand procedures of this protocol, and the relationship with other layers, are described in general termsin Recommendation Q.930/I.450 1. Annex M contains the additional basic call signallingrequirement for the support of private network interconnection for VPN applications.SourceITU-T Recomm
8、endation Q.931 was revised by ITU-T Study Group 11 (1997-2000) and wasapproved under the WTSC Resolution No. 1 procedure on the 15thof May 1998.ii Recommendation Q.931 (05/98)FOREWORDITU (International Telecommunication Union) is the United Nations Specialized Agency in the field oftelecommunication
9、s. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ ofthe ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuingRecommendations on them with a view to standardizing telecommunications on a worldwide basis.The World Telecommunicat
10、ion Standardization Conference (WTSC), which meets every four years,establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendationson these topics.The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down inWTSC Resolut
11、ion No. 1.In some areas of information technology which fall within ITU-Ts purview, the necessary standards areprepared on a collaborative basis with ISO and IEC.NOTEIn this Recommendation the term recognized operating agency (ROA) includes any individual, company,corporation or governmental organiz
12、ation that operates a public correspondence service. The termsAdministration, ROA and public correspondence are defined in the Constitution of the ITU (Geneva, 1992).INTELLECTUAL PROPERTY RIGHTSThe ITU draws attention to the possibility that the practice or implementation of this Recommendation mayi
13、nvolve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence,validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or othersoutside of the Recommendation development process.As of the date of approval of this
14、Recommendation, the ITU had not received notice of intellectual property,protected by patents, which may be required to implement this Recommendation. However, implementors arecautioned that this may not represent the latest information and are therefore strongly urged to consult theTSB patent datab
15、ase. ITU 1999All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means,electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU.Recommendation Q.931 (05/98) iiiCONTENTSPage1 General11.1 Scope of this R
16、ecommendation 11.2 Application to interface structures 12 Overview of call control . 12.1 Circuit-switched calls . 22.1.1 Call states at the user side of the interface. 22.1.2 Network call states. 32.2 Packet-mode access connections 42.2.1 Access connection states at the user side of the interface 4
17、2.2.2 Access connection states at the network side of the interface . 52.3 Temporary signalling connections 52.3.1 Call states at the user side of the interface. 62.3.2 Network call states. 62.4 States associated with the global call reference 72.4.1 Call states at the user side of the interface. 72
18、.4.2 Call states at the network side of the interface 73 Message functional definitions and content 83.1 Messages for circuit-mode connection control . 93.1.1 ALERTING . 103.1.2 CALL PROCEEDING. 113.1.3 CONNECT 123.1.4 CONNECT ACKNOWLEDGE 133.1.5 DISCONNECT 143.1.6 INFORMATION . 153.1.7 NOTIFY. 163.
19、1.8 PROGRESS. 173.1.9 RELEASE 183.1.10 RELEASE COMPLETE 193.1.11 RESUME. 193.1.12 RESUME ACKNOWLEDGE. 203.1.13 RESUME REJECT 203.1.14 SETUP. 213.1.15 SETUP ACKNOWLEDGE. 233.1.16 STATUS 243.1.17 STATUS ENQUIRY . 243.1.18 SUSPEND . 25iv Recommendation Q.931 (05/98)Page3.1.19 SUSPEND ACKNOWLEDGE . 253.
20、1.20 SUSPEND REJECT 263.2 Messages for packet-mode connection control. 263.2.1 ALERTING . 273.2.2 CALL PROCEEDING. 283.2.3 CONNECT 293.2.4 CONNECT ACKNOWLEDGE 293.2.5 DISCONNECT 303.2.6 PROGRESS. 303.2.7 RELEASE 313.2.8 RELEASE COMPLETE 323.2.9 SETUP. 333.2.10 STATUS 353.2.11 STATUS ENQUIRY . 353.3
21、Messages for user signalling bearer service control . 363.3.1 ALERTING . 373.3.2 CALL PROCEEDING. 373.3.3 CONGESTION CONTROL 383.3.4 CONNECT 383.3.5 CONNECT ACKNOWLEDGE 393.3.6 INFORMATION . 393.3.7 RELEASE 403.3.8 RELEASE COMPLETE 403.3.9 SETUP. 413.3.10 SETUP ACKNOWLEDGE. 433.3.11 STATUS 433.3.12
22、STATUS ENQUIRY . 443.3.13 USER INFORMATION 443.4 Messages with the global call reference . 453.4.1 RESTART . 453.4.2 RESTART ACKNOWLEDGE . 463.4.3 STATUS 464 General message format and information elements coding 474.1 Overview.474.2 Protocol discriminator. 474.3 Call reference 484.4 Message type. 5
23、0Recommendation Q.931 (05/98) vPage4.5 Other information elements 514.5.1 Coding rules. 514.5.2 Extensions of codesets. 554.5.3 Locking shift procedure. 564.5.4 Non-locking shift procedure 564.5.5 Bearer capability 584.5.6 Call identity . 654.5.7 Call state 664.5.8 Called party number 674.5.9 Called
24、 party subaddress . 684.5.10 Calling party number . 694.5.11 Calling party subaddress 714.5.12 Cause . 724.5.13 Channel identification 724.5.14 Congestion level 764.5.15 Date/time . 774.5.16 Display. 774.5.17 High layer compatibility 784.5.18 Keypad facility. 814.5.19 Low layer compatibility. 814.5.
25、20 More data. 934.5.21 Network-specific facilities. 934.5.22 Notification indicator. 944.5.23 Progress indicator 954.5.24 Repeat indicator. 964.5.25 Restart indicator. 974.5.26 Segmented message. 984.5.27 Sending complete 994.5.28 Signal. 994.5.29 Transit network selection. 1004.5.30 User-user 1014.
26、6 Information element for packet communications . 1024.6.1 Closed user group 1034.6.2 End-to-end transit delay. 1044.6.3 Information rate . 1054.6.4 Packet layer binary parameters 1074.6.5 Packet layer window size. 1084.6.6 Packet size . 109vi Recommendation Q.931 (05/98)Page4.6.7 Redirecting number
27、 . 1094.6.8 Reverse charging indication 1114.6.9 Transit delay selection and indication . 1125 Circuit-switched call control procedures 1125.1 Call establishment at the originating interface 1135.1.1 Call request 1135.1.2 B-channel selection Originating . 1145.1.3 Overlap sending. 1155.1.4 Invalid c
28、all information . 1165.1.5 Call proceeding 1165.1.6 Notification of interworking at the originating interface. 1175.1.7 Call confirmation indication 1185.1.8 Call connected . 1185.1.9 Call rejection 1185.1.10 Transit network selection. 1185.2 Call establishment at the destination interface 1185.2.1
29、Incoming call . 1195.2.2 Compatibility checking 1205.2.3 B-channel selection Destination . 1205.2.4 Overlap receiving. 1215.2.5 Call confirmation. 1235.2.6 Notification of interworking at the terminating interface 1265.2.7 Call accept . 1275.2.8 Active indication 1275.2.9 Non-selected user clearing.
30、 1275.3 Call clearing 1285.3.1 Terminology 1285.3.2 Exception conditions . 1285.3.3 Clearing initiated by the user. 1295.3.4 Clearing initiated by the network. 1295.3.5 Clear collision 1315.4 In-band tones and announcements 1315.5 Restart procedure 1315.5.1 Sending RESTART message. 1325.5.2 Receipt
31、of RESTART message . 1325.6 Call rearrangements 1345.6.1 Call suspension 1345.6.2 Call suspended. 134Recommendation Q.931 (05/98) viiPage5.6.3 Call suspend error 1355.6.4 Call re-establishment . 1355.6.5 Call resume errors 1365.6.6 Double suspension. 1365.6.7 Call rearrangement notification controll
32、ed by an NT2 1365.7 Call collisions . 1365.8 Handling of error conditions. 1375.8.1 Protocol discrimination error. 1375.8.2 Message too short 1375.8.3 Call reference error 1375.8.4 Message type or message sequence errors. 1385.8.5 General information element errors. 1395.8.6 Mandatory information el
33、ement errors 1395.8.7 Non-mandatory information element errors 1405.8.8 Data link reset 1425.8.9 Data link failure . 1425.8.10 Status enquiry procedure . 1435.8.11 Receiving a STATUS message 1435.9 User notification procedure. 1445.10 Basic telecommunication service identification and selection . 14
34、55.10.1 Additional procedures at the coincident S and T reference point 1455.10.2 Procedures for interworking with private ISDNs 1465.11 Signalling procedures for bearer capability selection . 1465.11.1 Procedures for the originating user to indicate bearer capability selection isallowed. 1465.11.2
35、Procedures for bearer capability selection at the destination side . 1485.11.3 Procedures for interworking with private ISDNs 1495.11.4 Channel selection. 1505.12 Signalling procedures for high layer compatibility selection 1515.12.1 Procedures for the originating user to indicate high layer compati
36、bilityselection is allowed 1515.12.2 Procedures for high layer compatibility selection at the destination side 1525.12.3 Procedures for interworking with private ISDNs 1526 Packet communication procedures . 1536.1 Outgoing access 1546.1.1 Circuit-switched access to PSPDN services (Case A). 1556.1.2
37、Access to the ISDN virtual circuit service (Case B) 156viii Recommendation Q.931 (05/98)Page6.2 Incoming access 1576.2.1 Access from PSPDN services (Case A). 1576.2.2 Access from the ISDN virtual circuit service (Case B) . 1586.3 X.25 virtual call establishment and release. 1636.3.1 Link layer estab
38、lishment and release . 1636.3.2 Packet layer virtual call set-up and release 1636.4 Call clearing 1646.4.1 B-channel access 1646.4.2 D-channel access . 1656.4.3 Additional error handling information. 1656.4.4 Cause mappings. 1666.5 Access collision 1697 User signalling bearer service call control pr
39、ocedures . 1697.1 General characteristics 1697.2 Call establishment. 1707.3 Transfer of USER INFORMATION messages. 1707.4 Congestion control of USER INFORMATION messages 1707.5 Call clearing 1717.6 Handling of error conditions. 1717.7 Restart procedures. 1728 Circuit-mode multirate (64 kbit/s base r
40、ate) procedures. 1728.1 Call establishment at the originating interface 1728.1.1 Compatibility information . 1728.1.2 Channel selection. 1728.1.3 Interworking 1748.2 Call establishment at the destination interface 1748.2.1 Compatibility information . 1748.2.2 Channel selection. 1748.2.3 Interworking
41、 1768.3 Call clearing 1768.4 Restart procedures. 1768.5 Call rearrangements 1769 List of system parameters . 1769.1 Timers in the network side 1769.2 Timers in the user side 176Recommendation Q.931 (05/98) ixPageAnnex A User side and network side SDL diagrams 182Annex B Compatibility and address che
42、cking 252B.1 Introduction. 252B.2 Calling side compatibility checking 253B.3 Called side compatibility and address checking . 253B.3.1 Checking of addressing information 253B.3.2 Network-to-user compatibility checking . 253B.3.3 User-to-user compatibility checking 253B.3.4 User action tables. 254B.4
43、 Interworking with existing networks 254Annex C Transit network selection. 256C.1 Selection not supported. 256C.2 Selection supported. 256Annex D Extensions for symmetric call operation . 257D.1 Additional message handling 257D.1.1 B-channel selection Symmetric interface . 257D.1.2 Call confirmation
44、. 257D.1.3 Clearing by the called user employing user-provided tones/announcements 258D.1.4 Active indication 258D.2 Timers for call establishment 258D.3 Call collisions . 258Annex E Network-specific facility selection 259E.1 Default provider 259E.2 Routing not supported. 259E.3 Routing supported. 2
45、59Annex F D-channel backup procedures 260F.0 Foreword. 260F.1 General 260F.2 D-channel backup procedure 261F.2.1 Role of each D-channel . 261F.2.2 Switch-over of D-channels 262Annex G Use of progress indicators . 262x Recommendation Q.931 (05/98)PageAnnex H Message segmentation procedures 264H.1 Int
46、roduction. 264H.2 Message segmentation 265H.3 Reassembly of segmented messages. 266Annex I Low layer information coding principles . 272I.1 Purpose 272I.2 Principles 272I.2.1 Definitions of types of information . 272I.2.2 Examination by network 273I.2.3 Location of type I information. 273I.2.4 Locat
47、ion of type II and III information 273I.2.5 Relationship between Bearer capability and Low layer capabilityinformation elements . 274I.3 Information classification . 275I.3.1 Examples for speech and 3.1 kHz audio bearer services. 275I.3.2 Examples for 64 kbit/s UDI circuit mode bearer service. 275I.
48、3.3 Examples for ISDN virtual-circuit bearer service . 277I.4 Scenarios outside the scope of ISDN standardization 278I.4.1 Examples for speech and 3.1 kHz audio bearer services. 278I.4.2 Examples for 64 kbit/s UDI circuit-mode bearer services. 279Annex J Low layer compatibility negotiation . 279J.1
49、General 279J.2 Low layer capability notification to the called user 279J.3 Low layer compatibility negotiation between users 280J.4 Low layer compatibility negotiation options 280J.5 Alternate requested values 280Annex K Procedures for establishment of bearer connection prior to call acceptance. 281K.1 General 281K.2 Procedures. 281Annex L Optional procedures for bearer service change 282Annex M Additional basic call signalling requirements for the support of private networkinterconnection for Virtual Private Network app
