INTERNATIONAL TELECOMMUNICATION UNION
`
`ITU-T
`
`TELECOMMUNICATION
`STANDARDIZATION SECTOR
`OF ITU
`
`Q.931
`
`(05/98)
`
`SERIES Q: SWITCHING AND SIGNALLING
`Digital subscriber Signalling System No. 1 – Network layer
`
`ISDN user-network interface layer 3
`specification for basic call control
`
`ITU-T Recommendation Q.931
`(Previously CCITT Recommendation)
`
`AT&T Exhibit 1039
`AT&T v. VoIP, IPR 2017-01382, Page 1
`
`

`

`ITU-T Q-SERIES RECOMMENDATIONS
`SWITCHING AND SIGNALLING
`
`SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE
`INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING
`FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN
`CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS
`SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5
`SPECIFICATIONS OF SIGNALLING SYSTEM No. 6
`SPECIFICATIONS OF SIGNALLING SYSTEM R1
`SPECIFICATIONS OF SIGNALLING SYSTEM R2
`DIGITAL EXCHANGES
`INTERWORKING OF SIGNALLING SYSTEMS
`SPECIFICATIONS OF SIGNALLING SYSTEM No. 7
`DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1
`General
`Data link layer
`Network layer
`User-network management
`Stage 3 description for supplementary services using DSS 1
`PUBLIC LAND MOBILE NETWORK
`INTERWORKING WITH SATELLITE MOBILE SYSTEMS
`INTELLIGENT NETWORK
`BROADBAND ISDN
`
`For further details, please refer to ITU-T List of Recommendations.
`
`Q.1–Q.3
`Q.4–Q.59
`Q.60–Q.99
`Q.100–Q.119
`Q.120–Q.249
`Q.250–Q.309
`Q.310–Q.399
`Q.400–Q.499
`Q.500–Q.599
`Q.600–Q.699
`Q.700–Q.849
`Q.850–Q.999
`Q.850–Q.919
`Q.920–Q.929
`Q.930–Q.939
`Q.940–Q.949
`Q.950–Q.999
`Q.1000–Q.1099
`Q.1100–Q.1199
`Q.1200–Q.1999
`Q.2000–Q.2999
`
`AT&T Exhibit 1039
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`ITU-T RECOMMENDATION Q.931
`
`ISDN USER-NETWORK INTERFACE LAYER 3 SPECIFICATION
`FOR BASIC CALL CONTROL
`
`Summary
`This Recommendation specifies the procedures for the establishing, maintaining and clearing of
`network connections at the ISDN user-network interface. These procedures are defined in terms of
`messages exchanged over the D-channel of basic and primary rate interface structures. The functions
`and procedures of this protocol, and the relationship with other layers, are described in general terms
`in Recommendation Q.930/I.450 [1]. Annex M contains the additional basic call signalling
`requirement for the support of private network interconnection for VPN applications.
`
`Source
`ITU-T Recommendation Q.931 was revised by ITU-T Study Group 11 (1997-2000) and was
`approved under the WTSC Resolution No. 1 procedure on the 15th of May 1998.
`
`Recommendation Q.931 (05/98)
`
`i
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`FOREWORD
`ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of
`telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of
`the ITU. The 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 World Telecommunication Standardization Conference (WTSC), which meets every four years,
`establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations
`on these topics.
`The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in
`WTSC Resolution No. 1.
`In some areas of information technology which fall within ITU-T's purview, the necessary standards are
`prepared on a collaborative basis with ISO and IEC.
`
`NOTE
`In this Recommendation the term recognized operating agency (ROA) includes any individual, company,
`corporation or governmental organization that operates a public correspondence service. The terms
`Administration, ROA and public correspondence are defined in the Constitution of the ITU (Geneva, 1992).
`
`INTELLECTUAL PROPERTY RIGHTS
`The ITU draws attention to the possibility that the practice or implementation of this Recommendation may
`involve 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 others
`outside of the Recommendation development process.
`As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property,
`protected by patents, which may be required to implement this Recommendation. However, implementors are
`cautioned that this may not represent the latest information and are therefore strongly urged to consult the
`TSB patent database.
`
` ITU 1999
`All 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.
`
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`1
`1.1
`1.2
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`2
`2.1
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`2.2
`
`2.3
`
`2.4
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`3
`3.1
`
`CONTENTS
`
`General........................................................................................................................
`Scope of this Recommendation ..................................................................................
`Application to interface structures..............................................................................
`
`Overview of call control .............................................................................................
`Circuit-switched calls .................................................................................................
`2.1.1 Call states at the user side of the interface.....................................................
`2.1.2 Network call states.........................................................................................
`Packet-mode access connections ................................................................................
`2.2.1 Access connection states at the user side of the interface..............................
`2.2.2 Access connection states at the network side of the interface .......................
`Temporary signalling connections..............................................................................
`2.3.1 Call states at the user side of the interface.....................................................
`2.3.2 Network call states.........................................................................................
`States associated with the global call reference..........................................................
`2.4.1 Call states at the user side of the interface.....................................................
`2.4.2 Call states at the network side of the interface ..............................................
`
`Message functional definitions and content................................................................
`Messages for circuit-mode connection control ...........................................................
`3.1.1 ALERTING ...................................................................................................
`3.1.2 CALL PROCEEDING...................................................................................
`3.1.3 CONNECT ....................................................................................................
`3.1.4 CONNECT ACKNOWLEDGE ....................................................................
`3.1.5 DISCONNECT..............................................................................................
`3.1.6
`INFORMATION ...........................................................................................
`3.1.7 NOTIFY.........................................................................................................
`3.1.8
`PROGRESS...................................................................................................
`3.1.9 RELEASE......................................................................................................
`3.1.10 RELEASE COMPLETE................................................................................
`3.1.11 RESUME.......................................................................................................
`3.1.12 RESUME ACKNOWLEDGE.......................................................................
`3.1.13 RESUME REJECT........................................................................................
`3.1.14 SETUP...........................................................................................................
`3.1.15 SETUP ACKNOWLEDGE...........................................................................
`3.1.16 STATUS ........................................................................................................
`3.1.17 STATUS ENQUIRY .....................................................................................
`3.1.18 SUSPEND .....................................................................................................
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`3.1.19 SUSPEND ACKNOWLEDGE .....................................................................
`3.1.20 SUSPEND REJECT ......................................................................................
`Messages for packet-mode connection control...........................................................
`3.2.1 ALERTING ...................................................................................................
`3.2.2 CALL PROCEEDING...................................................................................
`3.2.3 CONNECT ....................................................................................................
`3.2.4 CONNECT ACKNOWLEDGE ....................................................................
`3.2.5 DISCONNECT..............................................................................................
`3.2.6
`PROGRESS...................................................................................................
`3.2.7 RELEASE......................................................................................................
`3.2.8 RELEASE COMPLETE................................................................................
`3.2.9
`SETUP...........................................................................................................
`3.2.10 STATUS ........................................................................................................
`3.2.11 STATUS ENQUIRY .....................................................................................
`Messages for user signalling bearer service control ...................................................
`3.3.1 ALERTING ...................................................................................................
`3.3.2 CALL PROCEEDING...................................................................................
`3.3.3 CONGESTION CONTROL..........................................................................
`3.3.4 CONNECT ....................................................................................................
`3.3.5 CONNECT ACKNOWLEDGE ....................................................................
`3.3.6
`INFORMATION ...........................................................................................
`3.3.7 RELEASE......................................................................................................
`3.3.8 RELEASE COMPLETE................................................................................
`3.3.9
`SETUP...........................................................................................................
`3.3.10 SETUP ACKNOWLEDGE...........................................................................
`3.3.11 STATUS ........................................................................................................
`3.3.12 STATUS ENQUIRY .....................................................................................
`3.3.13 USER INFORMATION ................................................................................
`Messages with the global call reference .....................................................................
`3.4.1 RESTART .....................................................................................................
`3.4.2 RESTART ACKNOWLEDGE .....................................................................
`3.4.3
`STATUS ........................................................................................................
`
`General message format and information elements coding........................................
`Overview.....................................................................................................................
`Protocol discriminator.................................................................................................
`Call reference..............................................................................................................
`Message type...............................................................................................................
`
`3.2
`
`3.3
`
`3.4
`
`4
`4.1
`4.2
`4.3
`4.4
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`4.5
`
`4.6
`
`Other information elements ........................................................................................
`4.5.1 Coding rules...................................................................................................
`4.5.2
`Extensions of codesets...................................................................................
`4.5.3
`Locking shift procedure.................................................................................
`4.5.4 Non-locking shift procedure..........................................................................
`4.5.5 Bearer capability............................................................................................
`4.5.6 Call identity ...................................................................................................
`4.5.7 Call state ........................................................................................................
`4.5.8 Called party number ......................................................................................
`4.5.9 Called party subaddress .................................................................................
`4.5.10 Calling party number .....................................................................................
`4.5.11 Calling party subaddress................................................................................
`4.5.12 Cause .............................................................................................................
`4.5.13 Channel identification....................................................................................
`4.5.14 Congestion level ............................................................................................
`4.5.15 Date/time .......................................................................................................
`4.5.16 Display...........................................................................................................
`4.5.17 High layer compatibility................................................................................
`4.5.18 Keypad facility...............................................................................................
`4.5.19 Low layer compatibility.................................................................................
`4.5.20 More data.......................................................................................................
`4.5.21 Network-specific facilities.............................................................................
`4.5.22 Notification indicator.....................................................................................
`4.5.23 Progress indicator ..........................................................................................
`4.5.24 Repeat indicator.............................................................................................
`4.5.25 Restart indicator.............................................................................................
`4.5.26 Segmented message.......................................................................................
`4.5.27 Sending complete ..........................................................................................
`4.5.28 Signal.............................................................................................................
`4.5.29 Transit network selection...............................................................................
`4.5.30 User-user........................................................................................................
`Information element for packet communications .......................................................
`4.6.1 Closed user group ..........................................................................................
`4.6.2
`End-to-end transit delay.................................................................................
`4.6.3
`Information rate .............................................................................................
`4.6.4
`Packet layer binary parameters ......................................................................
`4.6.5
`Packet layer window size...............................................................................
`4.6.6
`Packet size .....................................................................................................
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`4.6.7 Redirecting number .......................................................................................
`4.6.8 Reverse charging indication ..........................................................................
`4.6.9
`Transit delay selection and indication ...........................................................
`
`Circuit-switched call control procedures ....................................................................
`Call establishment at the originating interface............................................................
`5.1.1 Call request....................................................................................................
`5.1.2 B-channel selection – Originating .................................................................
`5.1.3 Overlap sending.............................................................................................
`5.1.4
`Invalid call information .................................................................................
`5.1.5 Call proceeding..............................................................................................
`5.1.6 Notification of interworking at the originating interface...............................
`5.1.7 Call confirmation indication..........................................................................
`5.1.8 Call connected ...............................................................................................
`5.1.9 Call rejection..................................................................................................
`5.1.10 Transit network selection...............................................................................
`Call establishment at the destination interface............................................................
`5.2.1
`Incoming call .................................................................................................
`5.2.2 Compatibility checking..................................................................................
`5.2.3 B-channel selection – Destination .................................................................
`5.2.4 Overlap receiving...........................................................................................
`5.2.5 Call confirmation...........................................................................................
`5.2.6 Notification of interworking at the terminating interface..............................
`5.2.7 Call accept .....................................................................................................
`5.2.8 Active indication............................................................................................
`5.2.9 Non-selected user clearing.............................................................................
`Call clearing................................................................................................................
`5.3.1
`Terminology ..................................................................................................
`5.3.2
`Exception conditions .....................................................................................
`5.3.3 Clearing initiated by the user.........................................................................
`5.3.4 Clearing initiated by the network...................................................................
`5.3.5 Clear collision................................................................................................
`In-band tones and announcements ..............................................................................
`Restart procedure ........................................................................................................
`5.5.1
`Sending RESTART message.........................................................................
`5.5.2 Receipt of RESTART message .....................................................................
`Call rearrangements ....................................................................................................
`5.6.1 Call suspension..............................................................................................
`5.6.2 Call suspended...............................................................................................
`
`5
`5.1
`
`5.2
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`5.3
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`5.4
`5.5
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`5.6
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`5.6.3 Call suspend error..........................................................................................
`5.6.4 Call re-establishment .....................................................................................
`5.6.5 Call resume errors..........................................................................................
`5.6.6 Double suspension.........................................................................................
`5.6.7 Call rearrangement notification controlled by an NT2..................................
`Call collisions .............................................................................................................
`Handling of error conditions.......................................................................................
`5.8.1
`Protocol discrimination error.........................................................................
`5.8.2 Message too short ..........................................................................................
`5.8.3 Call reference error........................................................................................
`5.8.4 Message type or message sequence errors.....................................................
`5.8.5 General information element errors...............................................................
`5.8.6 Mandatory information element errors..........................................................
`5.8.7 Non-mandatory information element errors ..................................................
`5.8.8 Data link reset................................................................................................
`5.8.9 Data link failure.............................................................................................
`5.8.10 Status enquiry procedure ...............................................................................
`5.8.11 Receiving a STATUS message......................................................................
`User notification procedure.........................................................................................
`Basic telecommunication service identification and selection ...................................
`5.10.1 Additional procedures at the coincident S and T reference point..................
`5.10.2 Procedures for interworking with private ISDNs ..........................................
`Signalling procedures for bearer capability selection .................................................
`5.11.1 Procedures for the originating user to indicate bearer capability selection is
`allowed...........................................................................................................
`5.11.2 Procedures for bearer capability selection at the destination side .................
`5.11.3 Procedures for interworking with private ISDNs ..........................................
`5.11.4 Channel selection...........................................................................................
`Signalling procedures for high layer compatibility selection......................................
`5.12.1 Procedures for the originating user to indicate high layer compatibility
`selection is allowed........................................................................................
`5.12.2 Procedures for high layer compatibility selection at the destination side......
`5.12.3 Procedures for interworking with private ISDNs ..........................................
`
`Packet communication procedures .............................................................................
`Outgoing access ..........................................................................................................
`6.1.1 Circuit-switched access to PSPDN services (Case A)...................................
`6.1.2 Access to the ISDN virtual circuit service (Case B)......................................
`
`5.7
`5.8
`
`5.9
`5.10
`
`5.11
`
`5.12
`
`6
`6.1
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`6.2
`
`6.3
`
`6.4
`
`6.5
`
`7
`7.1
`7.2
`7.3
`7.4
`7.5
`7.6
`7.7
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`8
`8.1
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`8.2
`
`8.3
`8.4
`8.5
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`9
`9.1
`9.2
`
`Incoming access ..........................................................................................................
`6.2.1 Access from PSPDN services (Case A).........................................................
`6.2.2 Access from the ISDN virtual circuit service (Case B) .................................
`X.25 virtual call establishment and release.................................................................
`6.3.1
`Link layer establishment and release .............................................................
`6.3.2
`Packet layer virtual call set-up and release....................................................
`Call clearing................................................................................................................
`6.4.1 B-channel access............................................................................................
`6.4.2 D-channel access ...........................................................................................
`6.4.3 Additional error handling information...........................................................
`6.4.4 Cause mappings.............................................................................................
`Access collision ..........................................................................................................
`
`User signalling bearer service call control procedures ...............................................
`General characteristics................................................................................................
`Call establishment.......................................................................................................
`Transfer of USER INFORMATION messages...........................................................
`Congestion control of USER INFORMATION messages..........................................
`Call clearing................................................................................................................
`Handling of error conditions.......................................................................................
`Restart procedures.......................................................................................................
`
`Circuit-mode multirate (64 kbit/s base rate) procedures.............................................
`Call establishment at the originating interface............................................................
`8.1.1 Compatibility information .............................................................................
`8.1.2 Channel selection...........................................................................................
`8.1.3
`Interworking ..................................................................................................
`Call establishment at the destination interface............................................................
`8.2.1 Compatibility information .............................................................................
`8.2.2 Channel selection...........................................................................................
`8.2.3
`Interworking ..................................................................................................
`Call clearing................................................................................................................
`Restart procedures.......................................................................................................
`Call rearrangements ....................................................................................................
`
`List of system parameters ...........................................................................................
`Timers in the network side..........................................................................................
`Timers in the user side................................................................................................
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`Annex A – User side and network side SDL diagrams............................................................
`
`Annex B – Compatibility and address checking ......................................................................
`B.1
`Introduction.................................................................................................................
`B.2
`Calling side compatibility checking............................................................................
`B.3
`Called side compatibility and address checking .........................................................
`B.3.1 Checking of addressing information..............................................................
`B.3.2 Network-to-user compatibility checking .......................................................
`B.3.3 User-to-user compatibility checking..............................................................
`B.3.4 User action tables...........................................................................................
`Interworking with existing networks ..........................................................................
`
`B.4
`
`Annex C – Transit network selection.......................................................................................
`C.1
`Selection not supported...............................................................................................
`C.2
`Selection supported.....................................................................................................
`
`Annex D – Extensions for symmetric call operation ...............................................................
`D.1
`Additional message handling......................................................................................
`D.1.1 B-channel selection – Symmetric inter