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ANNEX B (to Recommendation Q.764) State transition diagrams Note - Should any conflict arise between the text and the SDL definition, the textual description is taken as definitive. B.1 General This Annex contains the description of the signalling procedures described in this Recommendation in the form of state transition diagrams according to the CCITT Specification and Description Language (SDL). In order to facilitate functional description, the ISDN User Part (ISDN-UP) signalling procedure is divided into main functional blocks, as shown in Figure B-1/Q.764. These blocks are as follows: 1) Signalling procedure control (SPRC) SPRC provides procedures for sending ISDN-UP messages to Level 3 (SCCP or MTP) and distributing received messages to the other ISDN-UP functional blocks. 2) Call processing control (CPC) CPC provides call control procedures for realizing basic circuit switched service according to user's request. 3) Circuit supervision control (CSC) CSC provides procedures for circuit supervision control for maintenance purpose and for recovery from abnormal situation. B.2 Drafting convention a) External inputs and outputs are used for interactions with a remote exchange and interaction between SPRC and the other functional blocks. Internal inputs and outputs are used for interactions within each functional block, e.g., to indicate control of time-out. For these interactions, input and output symbols are used as shown in Figure B-2/Q.764. b) Inputs and outputs symbols contain as part of their name acronyms of their source and destination functional block names with an arrow in between, e.g., Blocking BLS -> CPC. c) A simple example of SDL diagram according to the above conventions is shown in Figure B-3/Q.764. B.3 Abbreviations, timers and primitives B.3.1 Abbreviations 1) Table B-1/Q.764: Signalling procedure control. 2) Table B-2/Q.764: Call processing control. 3) Table B-3/Q.764: Circuit supervision control. B.3.2 Timers Timers used in the ISDN-UP SDL diagrams are shown in Table B-4/Q.764. B.3.3 Primitives Primitives used over the interface between call control and ISDN-UP are shown in Table B-5/Q.764. B.4 State transition diagrams and SDL diagrams Each ISDN-UP main functional block is further subdivided into the functional blocks. Functional diagrams and simple state transition diagrams for each main functional block are shown below: 1) Signalling procedure control (SPRC) - Figure B-4/Q.764 Functional diagrams - Figure B-5/Q.764 State transition diagrams 2) Call processing control (CPC) - Figure B-6/Q.764 Functional diagrams - Figures B-7/Q.764 to B-9/Q.764 Fascicle VI.8 - Rec. Q.764 PAGE67 State transition diagrams 3) Circuit supervision control (CSC) - Figure B-10/Q.764 Functional diagrams - Figures B-11/Q.764 to B-18/Q.764 State transition diagrams The ISDN-UP SDL diagrams are described based on the three-blocks approach. In this approach, call control, which provides signalling-independent functions such as connect-through, circuit selection and digits analysis, is outside the ISDN-UP. These functions are described only in SS 1-3. The ISDN-UP diagrams are provided for the above subdivided functional blocks, as shown below: 1) Signalling procedure control (SPRC) - Figure B-19/Q.764 Message sending control - Figure B-20/Q.764 Message distributing control 2) Call processing control (CPC) - Figure B-21/Q.764 Call processing control incoming (CPCI) - Figure B-22/Q.764 Call processing control outgoing (CPCO) - Figure B-23/Q.764 Continuity check incoming (CCI) - Figure B-24/Q.764 Continuity check outgoing (CCO) 3) Circuit supervision control (CSC) - Figure B-25/Q.764 Blocking/unblocking message sending (BLS) - Figure B-26/Q.764 Blocking/unblocking message reception (BLR) - Figure B-27/Q.764 Maintenance oriented circuit group blocking/unblocking sending (MGBS) - Figure B-28/Q.764 Blocking/unblocking reception (MGBR) - Figure B-29/Q.764 Hardware failure oriented locally blocking state (HLB) - Figure B-30/Q.764 PAGE76 Fascicle VI.8 - Rec. Q.764 Hardware failure oriented remotely blocking state (HRB) - Figure B-31/Q.764 Hardware failure oriented circuit group blocking/unblocking sending (HGBS): - Figure B-32/Q.764 Hardware failure oriented circuit group blocking/unblocking reception (HGBR) - Figure B-33/Q.764 Circuit reset sending (CRS) - Figure B-34/Q.764 Circuit reset reception (CRR) - Figure B-35/Q.764 Circuit group reset sending (CGRS) - Figure B-36/Q.764 Circuit group reset reception (CGRR) - Figure B-37/Q.764 Continuity recheck sending (CRCS) - Figure B-38/Q.764 Continuity recheck reception (CRCR) - Figure B-39/Q.764 Circuit group query sending (CQS) - Figure B-40/Q.764 Circuit group query reception (CQR) Figure B-1/Q.764 - T1116960-88 Figure B-2/Q.764 - T6970-88 Figure B-3/Q.764 - T1116980-88 TABLE B-1/Q.764 Signalling procedure control acronym Acronym Description BLR Blocking/Unblocking Message Reception BLS Blocking/Unblocking Message Sending CCO Fascicle VI.8 - Rec. Q.764 PAGE67 Continuity Check Outgoing CCI Continuity Check Incoming CGRS Circuit Group Reset Sending CGRR Circuit Group Reset Reception CPC Call Processing Control CRR Circuit Reset Reception CRS Circuit Reset Sending Functional CSC Circuit Supervision Control block name SPRC Signalling Procedure Control MGBR Maintenance Oriented Circuit Group Blocking/Unblocking Reception HGBR Hardware Failure Oriented Circuit Group Blocking/Unblocking Reception MGBS PAGE76 Fascicle VI.8 - Rec. Q.764 Maintenance Oriented Circuit Group Blocking/Unblocking Sending HGBS Hardware Failure Oriented Circuit Group Blocking/Unblocking Sending CRCR Continuity Recheck Control Reception CRCS Continuity Recheck Control Sending CQR Circuit Group Query Reception CQS Circuit Group Query Sending MSDC Message Sending Control MDSC Message Distributing Control BLA Blocking Acknowledgement BLO Blocking GRA Group Reset Acknowledgement GRS Fascicle VI.8 - Rec. Q.764 PAGE67 Group Reset CQR Circuit Group Query Response CQM Circuit Group Query UBA Unblocking Acknowledgement Message UBL Unblocking type CCR Continuity Check Request CGB Circuit Group Blocking CGBA Circuit Group Blocking Acknowledgement CGU Circuit Group Unblocking CGUA Circuit Group Unblocking Acknowledgement RSC Reset Circuit CFN PAGE76 Fascicle VI.8 - Rec. Q.764 Confusion Fascicle VI.8 - Rec. Q.764 PAGE67 TABLE B-2/Q.764 Call processing control acronym Acronym Description OGC Outgoing Trunk Circuit General ICC Incoming Trunk Circuit CCH Continuity Check Indicator CC Call control SPRC Signalling Procedure Control CPC Call Processing Control BLR Blocking/Unblocking Message Reception BLS Blocking/Unblocking Message Sending CCO Continuity Check Outgoing CCI PAGE76 Fascicle VI.8 - Rec. Q.764 Continuity Check Incoming CGRR Circuit Group Reset Reception Functional CRR Circuit Reset Reception block name CRS Circuit Reset Sending CPCI Call Processing Control Incoming CPCO Call Processing Control Outgoing MGBR Maintenance Oriented Circuit Group Unblocking/Blocking Reception HGBR Hardware Failure Oriented Circuit Group Blocking/Unblocking Reception MGBS Maintenance Oriented Circuit Group Unblocking/Blocking Sending HGBS Hardware Failure Oriented Circit Group Blocking/Unblocking Sending CRCR Continuity Recheck Reception CRCS Fascicle VI.8 - Rec. Q.764 PAGE67 Continuity Recheck Sending ACM Address Complete ANM Answer COT Continuity CPG Call Progress IAM Initial Address Message SUS Suspend (network-or user-initiated) type RES Resume (network-or user-initiated) REL Release RLC Release Complete FOT Forward Transfer SAM PAGE76 Fascicle VI.8 - Rec. Q.764 Subsequent Address CON Connect Fascicle VI.8 - Rec. Q.764 PAGE67 TABLE B-3/Q.764 Circuit supervision control acronym Acronym Description BLR Blocking/Unblocking Reception BLS Blocking/Unblocking Sending CRS Circuit Reset Sending CRR Circuit Reset Reception CGRS Circuit Group Reset Sending CGRR Circuit Group Reset Reception MGBR Maintenance Oriented Circuit Group Blocking/Unblocking Reception Functional HGBR Hardware Failure Oriented Circuit Group Blocking/Unblocking Reception block name MGBS Maintenance Oriented Circuit Group Blocking/Unblocking Sending HGBS PAGE76 Fascicle VI.8 - Rec. Q.764 Hardware Failure Oriented Circuit Group Blocking/Unblocking Sending CRCR Continuity Recheck Reception CRCS Continuity Recheck Sending CQR Circuit Group Query Reception CQS Circuit Group Query Sending HRB Hardware Failure Oriented Remotely Blocking HLB Hardware Failure Oriented Locally Blocking State BLA Blocking Acknowledgement BLO Blocking COT Continuity CQR Circuit Group Query Response CQM Fascicle VI.8 - Rec. Q.764 PAGE67 Circuit Group Query GRA Group Reset Acknowledgement GRS Group Reset RLC Release Complete Message RSC Reset Circuit type UBA Unblocking Acknowledgement UBL Unblocking CGB Circuit Group Blocking CGBA Circuit Group Blocking Acknowledgement CCR Continuity Check Request CGU Circuit Group Unblocking CGUA PAGE76 Fascicle VI.8 - Rec. Q.764 Circuit Group Unblocking Acknowledgement REL Release Fascicle VI.8 - Rec. Q.764 PAGE67 TABLE B-4/Q.764 Timer Timer Symbol Time-out value First RLC timer T1 4-15 s Second RLC timer T5 1 min RES timer (network) T6 Covered in Q.118 ACM timer T7 20-30 s COT timer T8 10-15 s ANM timer T9 Interval specified in Q.118 First BLA timer T12 4-15 s Second BLA timer T13 1 min First UBA timer T14 4-15 s Second UBA timer T15 PAGE76 Fascicle VI.8 - Rec. Q.764 1 min First RSC response timer T16 4-5 s Second RSC response timer T17 1 min First CGBA timer T18 4-15 s Second CGBA timer T19 1 min First CGUA timer T20 4-15 s Second CGUA timer T21 1 min First GRA timer T22 4-15 s Second GRA Timer T23 1 min Continuity tone timer T24 2 s CCR timing timer T25 1-10 s CCR response timer T26 Fascicle VI.8 - Rec. Q.764 PAGE67 1-3 min CCR receive timer T27 4 min CQR timer T28 10 s PAGE76 Fascicle VI.8 - Rec. Q.764 TABLE B-5/Q.764 Primitives Primitive ISDN-UP message Interface SETUP REQUEST IAM Interface between INDICATION ANM, CON CC and CPC RESPONSE RELEASE CONFIRMATION REL, RLC RESET INDICATION RSC, RLC RESPONSE GRS, GRA FORWARD TRANSFER REQUEST FOT Fascicle VI.8 - Rec. Q.764 PAGE67 INDICATION PROC ACM (Other) ALERT CPG, ACM (Subscriber free) INFO SAM PROG a) CPG, ACM (Interworking, Q.931 progress indicator) IBI b) CPG (In-band information) ACM (In-band information SUSPENDED SUS RESUMED PAGE76 Fascicle VI.8 - Rec. Q.764 RES BLOCKING REQUEST BLO, BLA Interface between INDICATION CGB, CGBA CC and CSC RESPONSE CONFIRMATION UNBLOCKING UBL, UBA CGU, CGUA CCT GROUP QUERY CQM, CQR STOP c) REQUEST - Fascicle VI.8 - Rec. Q.764 PAGE67 CONFIRMATION CONTINUITY RECHECK CCR RESET GRS, GRA RSC, RLC PAGE76 Fascicle VI.8 - Rec. Q.764 TABLE B-5/Q.764 (cont.) Primitive ISDN-UP message Interface CALL FAILURE c) INDICATION - Interface between CC and CPC REATTEMPT c) CONTINUITY REPORT REQUEST COT INDICATION MAINTENANCE SYSTEM c) INDICATION - Interface between CC and CSC START RESET c) CC and CPC a Prog (network): Interworking Prog (access): Q.931 progress indivator b) IBI: In-band information available c) Locale primitive Figure B-4/Q.764 - T1116990-88 Fascicle VI.8 - Rec. Q.764 PAGE67