1、 - STD.ITU-T RECMN Q.712-ENGL Lb m LiBb259L Ob33128 883 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.712 (07196) SERIES Q: SWITCHING AND SIGNALLING Specifications of Signalling System No. 7 - Signalling connection control part Definition and function
2、of signalling connection control part messages ITU-T Recommendation Q.712 (Previously CCITT Recommendation) STD-ITU-T RECMN Q-71Z-ENGL 199b m 4b2571 Ob33L29 7LT = Telephone user part ISDN supplementary services Data user part , Signalling System No. 7 management ISDN user part Transaction capabiliti
3、es application part Test specification Q3 interface DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK BROADBAND ISDN ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVI
4、CE INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS SPECIFICATION OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SIGNALLING SYSTEM RI SPECIFICATI
5、ONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 General Message transfer part Simplified message transfer part Q.1-(2.3 Q.4-Q.59 Q. 100-Q.l 19 Q.60-Q.99 Q. 120-Q.249 Q.250-Q.309 Q.310-(2.399 Q.400-Q.499 Q.500-(2.599 Q.60O-Q ,
6、699 Q.700-Q. 849 Q ,700 Q.701-Q.709 Q.710 Q.711-Wi9 Q.730-Q.739 Q. 720-Q. 729 Q. 740-Q. 749 (2.7504.759 (2.7604.769 Q.770-Q.779 Q.780-Q.799 (2.8004.849 Q.850-Q.999 Q. 1000-Q. 1 O99 Q.1100-Q.1199 Q. 1200-Q. 1999 Q ,2000-Q .2999 _ For further details, please refer to ITU-T List of Recommendations. - -
7、 STDSITU-T RECMN Q.712-ENGL 177b D 4b257L Ob33130 431 = ITU-T RECOMMENDATION Q.712 DEFINITION AND FUNCTION OF SIGNALLING CONNECTION CONTROL PART MESSAGES Summary The Signalling Connection Control Part (SCCP) messages are used by the peer-to-peer protocol. All messages are uniquely identified by mean
8、s of a message type code, which is to be found in all the messages. The meaning and definition of the various parameter fields contained in these messages are specified in clause 2. The actual inclusion of these parameter fields in a given message depends on the class of protocol and is specified in
9、 clause 3. Source ITU-T Recommendation 4.712 was revised by ITU-T Study Group 11 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 9th of July 1996. STD-ITU-T RECMN Q.712-ENGL L99b W 48b259L Ob33333 378 W FOREWORD IT (International Telecommunication Union) is the United N
10、ations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (IT-T) is a permanent organ of the IT. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telec
11、ommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of
12、the IT-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-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
13、conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The IT draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The IT ta
14、kes 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 hadhad not received notice of intellectu
15、al 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. O ITU 1997 All rights reserved. No part of this publi
16、cation 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 IT. II Recommendation Q.712 (07196) 1 STD-ITU-T RECMN Q.712-ENGL L77b D 4bZ57L Ob33132 204 CONTENTS Page 1 Signalling nnection conm
17、l part messages . 3 6 2 SCCP message parameters 3 . Inclusion of fields in the messages 8 8 8 4 References 4.1 Normative references 4.2 Informative references Recommendation Q.712 (07/96) . 111 - - STD.ITU-T RECMN Q-712-ENGL L99b D 48b257L Ob33133 140 m Recommendation Q.7.2 DEFINITION AND FUNCTION O
18、F SIGNALLING CONNECTION CONTROL PART MESSAGES (revised in 1996) 1 The Signalling Connection Control Part (SCCP) messages are used by the peer-to-peer protocol. All messages are uniquely identified by means of a message type code, which is to be found in all the messages. The meaning and definition o
19、f the various parameter fields contained in these messages are specified in clause 2. The actual inclusion of these parameter fields in a given message depends on the class of protocol and is specified in clause 3. 1.1 connection confirm (CC): A Connection Confirm message is initiated by the called
20、SCCP to indicate to the calling SCCP that it has performed the setup of the signalling connection. On reception of a Connection ConJirm message, the calling SCCP completes the setup of the signalling connection, if possible. It is used during connection establishment phase by connection-oriented pro
21、tocol class 2 or 3. 1.2 connection request (CR): A Connection Request message is initiated by a calling SCCP to a called SCCP to request the setting up of a signalling connection between the two entities. The required characteristics of the signalling connection are carried in various parameter fiel
22、ds. On reception of a Connection Request message, the called SCCP initiates the setup of the signalling connection, if possible. It is used during connection establishment phase by connection-oriented protocol class 2 or 3. 1.3 connection refused (CREF): A Connection Rejsed message is initiated by t
23、he called SCCP or an intermediate node SCCP to indicate to the calling SCCP that the setup of the signalling connection has been refused. Signalling connection control part messages It is used during connection establishment phase by connection-oriented protocol class 2 or 3. 1.4 window flow control
24、 mechanism, which has been selected for the data transfer phase. It is used during the data transfer phase in protocol class 3. 1.5 to pass transparently SCCP user data between two SCCP nodes. It is used during the data transfer phase in protocol class 2 only. 1.6 data form 2 (DT2): A Data Form 2 me
25、ssage is sent by either end of a signalling connection to pass transparently SCCP user data between two SCCP nodes and to acknowledge messages flowing in the other direction. It is used during the data transfer phase in protocol class 3 only. 1.7 expedited data (ED): An Expedited Data message functi
26、ons as a Data Form 2 message but includes the ability to bypass the flow control mechanism which has been selected for the data transfer phase. It may be sent by either end of the signalling connection. It is used during the data transfer phase in protocol class 3 only. data acknowledgement (AK): A
27、Data Acknowledgement message is used to control the data form 1 (DT1): A Data Form 1 message is sent by either end of a signalling connection Recommendation Q.712 (07/96) 1 STD.ITU-T RECMN 0-712-ENGL L97b m 4b2571 Ob33134 O87 1.8 expedited data acknowledgement (EA): An Expedited Data Acknowledgement
28、 message is used to acknowledge an Expedited Data message. Every ED message has to be acknowledged by an EA message before another ED message may be sent. It is used during the data transfer phase in protocol class 3 only. 1.9 inactivity test (IT): An Inactiviw Test message may be sent periodically
29、by either end of a signalling connection section to check if this signalling connection is active at both ends, and to audit the consistency of connection data at both ends. It is used in protocol classes 2 and 3. 1.10 of any protocol errors. It is used during the data transfer phase in protocol cla
30、sses 2 and 3. 1.11 released LSD): A Released message is sent, in the forward or backward direction, to indicate that the sending SCCP wants to release a signalling connection and the associated resources at the sending SCCP have been brought into the disconnect pending condition. It also indicates t
31、hat the receiving node should release the connection and any other associated resources as well. It is used during connection release phase in protocol classes 2 and 3. 1.12 release complete (RLC): A Release Complete message is sent in response to the Released message indicating that the Released me
32、ssage has been received, and the appropriate procedures have been completed. It is used during connection release phase in protocol classes 2 and 3. 1.13 reset confirm (RSC): A Reset CanJirm message is sent in response to a Reset Request message to indicate that Reset Request has been received and t
33、he appropriate procedure has been completed. It is used during the data transfer phase in protocol class 3. 1.14 wants to initiate a reset procedure (re-initialization of sequence numbers) with the receiving SCCP. It is used during the data transfer phase in protocol class 3. 1.15 subsystem-allowed
34、(SSA): A Subsystem-Allowed message is sent to concerned destinations to inform those destinations that a subsystem which was formerly prohibited is now allowed or that a SCCP which was formerly unavailable is now available. It is used for SCCP management. 1.16 subsystem-out-of-service-grant (SOG): A
35、 Subsystem-Out-of-Service-Grant message is sent, in response to a Subsystem-Out-of-Service-Request message, to the requesting SCCP if both the requested SCCP and the backup of the affected subsystem agree to the request. It is used for SCCP subsystem management. 1.17 subsystem-out-of-service-request
36、 (SOR): A Subsystem-Out-ofService-Request message is used to allow subsystems to go out-of-service without degrading performance of the network. When a subsystem wishes to go out-of-service, the request is transferred by means of a Subsystem-Out-of- Service-Request message between the SCCP at the su
37、bsystems node and the SCCP at the duplicate subsystems, node. It is used for SCCP subsystem management. protocol data unit error (ERR): A Protocol Data Unit Error message is sent on detection reset request (RSR): A Reset Request message is sent to indicate that the sending SCCP 2 Recommendation Q.71
38、2 (07/96) STD.ITU-T RECMN 8.712-ENGL 19b m 48b259L Ob33135 T13 m 1.18 subsystem-prohibited (SSP): A Subsystem-Prohibited message is sent to concerned destinations to inform SCCP Management (SCMG) at those destinations of the failure of a subsystem. It is used for SCCP subsystem management. 1.19 of a
39、 subsystem marked prohibited or the status of an SCCP marked unavailable. It is used for SCCP management. 1.20 connectionless mode. It is used in connectionless protocol classes O and 1. 1.21 unitdata service (UDTS): A Unitdata Service message is used to indicate to the originating SCCP that a UDT s
40、ent cannot be delivered to its destination. Exceptionally and subject to protocol intenvorking considerations, a UDTS might equally be used in response to an XUDT or LUDT message. A UDTS message is sent only when the option field in that UDT is set to “return on error“. It is used in connectionless
41、protocol classes O and 1. 1.22 to send data (along with optional parameters) in a connectionless mode. It is used in connectionless protocol classes O and 1. 1.23 extended unitdata service (XUDTS): An Extended Unitdata Service message is used to indicate to the originating SCCP that an XUDT cannot b
42、e delivered to its destination. Exceptionally and subject to protocol intenvorking considerations, an XUDTS might equally be used in response to a UDT or LUDT message. An XUDTS message is sent only when the return message on error option in the XUDT (or possibly LUDT) is set. It is used in connectio
43、nless protocol classes O and i. 1.24 subsystem congested (SSC): A Subsystem Congested message is sent by an SCCP node when it experiences congestion. 1.25 long unitdata (LUDT): A Long Unitdata message is used by the SCCP to send data (along with optional parameters) in a connectionless mode. When MT
44、P capabilities according to Recommendation 4.2210 are present, it allows sending of NSDU sizes up to 3952 octets without segmentation. It is used in Connectionless protocol classes O and 1. 1.26 long unitdata service (LUDTS): A Long Unitdata Service message is used to indicate to the originating SCC
45、P that an LUDT cannot be delivered to its destination. An LUDTS message is sent only when the return message on error option in the LUDT is set. It is used in connectionless protocol classes O and i. subsystem-status-test (SST): A Subsystem-Status-Test message is sent to veri the status unitdata (UD
46、T): A Unitdata message can be used by an SCCP wanting to send data in a extended unitdata (XUDT): An Extended Unitdata message is used by the SCCP wanting 2 SCCP message parameters 2.1 affected point code: The “affected point code“ identifies a signalling point where the affected subsystem or SCCP i
47、s located. 2.2 affected subsystem number: The “affected subsystem number“ parameter field identifies the SCCP or a subsystem which is failed, withdrawn, congested or allowed. In the case of SST messages, it also identifies the subsystem being audited. In the case of SOR or SOG messages, it Recommend
48、ation 4.712 (07196) 3 STD-ITU-T RECMN Q-712-ENGL L97b D 48b257L Ob3313b 95T m identifies a subsystem requesting to go out-of-service. The SSN for SCMG is used to denote the SCCP as a whole in the SSA, SSC and SST messages. 2.3 callinghalled party address: The “calling/called party address“ parameter
49、 field, together with additional information given by the MTP, contains enough information to uniquely identi the originatioddestination signalling point and/or the SCCP service access point. It can be any combination of a global title (dialled digits, for example), a signalling point code, and a subsystem number. The subsystem number (SSN) identifies an SCCP user when provided. In order to allow the interpretation of this address, it begins with an address indicator indicating which information elements are present. The address indicator
