1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Q.711 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2001) SERIES Q: SWITCHING AND SIGNALLING Specifications of Signalling System No. 7 Signalling connection control part (SCCP) Functional description of the signalling connection control part ITU-T R
2、ecommendation Q.711 (Formerly CCITT Recommendation) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLI
3、CABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 Q.120Q.249 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309 SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399 SPECIFICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKIN
4、G OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 General Q.700 Message transfer part (MTP) Q.701Q.709 Signalling connection control part (SCCP) Q.711Q.719 Telephone user part (TUP) Q.720Q.729 ISDN supplementary services Q.730Q.739 Data user part Q.740Q.749 Sign
5、alling System No. 7 management Q.750Q.759 ISDN user part Q.760Q.769 Transaction capabilities application part Q.770Q.779 Test specification Q.780Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOB
6、ILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 BROADBAND ISDN Q.2000Q.2999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Q.711 (03/2001) i ITU-T Recommendation Q.711 Functional description of t
7、he signalling connection control part Summary The Q.71X-series Recommendations defines the services of the SCCP. The SCCP is part of SS No. 7 and provides, above the MTP network or networks, connectionless, connection-oriented, routing and management services. Source ITU-T Recommendation Q.711 was r
8、evised by ITU-T Study Group 11 (2001-2004) and approved under the WTSA Resolution 1 procedure on 1 March 2001. ii ITU-T Q.711 (03/2001) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Stan
9、dardization Sector (ITU-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 World Telecommunication Standardization Assembly (WTSA), w
10、hich 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 ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within
11、 ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS IT
12、U draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU memb
13、ers or others outside of the Recommendation development process. As of the date of approval of this Recommendation, 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 no
14、t represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2001 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 permiss
15、ion in writing from ITU. ITU-T Q.711 (03/2001) iii CONTENTS Page 1 Scope and field of application 1 2 References. 2 2.1 Normative references 2 2.2 Informative references 2 3 Definitions 3 4 Abbreviations and acronyms 3 5 General characteristics 4 5.1 Technique of description 4 5.2 Primitives 5 5.3 P
16、eer-to-peer communication. 5 5.4 Model of the connection-oriented network service 6 5.5 Model of the connectionless network service. 6 5.6 Contents of the Q.71X-series Recommendations . 7 6 Services provided by the SCCP 7 6.1 Connection-oriented services 7 6.1.1 Temporary signalling connections. 8 6
17、.1.2 Permanent signalling connections . 19 6.2 Connectionless services 20 6.2.1 Description. 20 6.2.2 Primitives and parameters of the connectionless service 21 6.2.3 State transition diagram. 24 6.3 SCCP management . 24 6.3.1 Description. 24 6.3.2 Primitives and parameters of the SCCP management. 2
18、4 7 Definition of the lower boundary of the SCCP. 27 7.1 MTP-SAP 27 7.2 MTP primitives and parameters 27 7.2.1 TRANSFER. 28 7.2.2 PAUSE. 28 7.2.3 RESUME. 29 7.2.4 STATUS 29 7.2.5 Notification of completion of MTP restart procedure . 29 7.3 State transition diagram 29 8 Functions provided by the SCCP
19、 33 iv ITU-T Q.711 (03/2001) Page 8.1 Connection-oriented functions 33 8.1.1 Functions for temporary signalling connections . 33 8.1.2 Functions for permanent signalling connections. 33 8.2 Connectionless service functions 34 8.3 Management functions 34 8.4 Routing and translation functions. 34 ITU-
20、T Q.711 (03/2001) 1 ITU-T Recommendation Q.711 Functional description of the signalling connection control part 1 Scope and field of application The Signalling Connection Control Part (SCCP) provides additional functions to the Message Transfer Part (MTP) to cater for both connectionless as well as
21、connection-oriented network services to transfer circuit-related and non-circuit-related signalling information and other types of information between exchanges and specialized centres in telecommunication networks (e.g. for management and maintenance purposes) via a Signalling System No. 7 network.
22、 A functional block above the message transfer part performs the functions and procedures of the SCCP. The SCCP is capable of using the services of the MTP as described in ITU-T Q.701 to ITU-T Q.707, and/or in ITU-T Q.2210. The combination of the MTP and the SCCP is called “network service part“ (NS
23、P). The network service part follows the principles of the OSI-reference model as defined in ITU-T X.200, providing a subset of the layer 3 services defined in ITU-T X.213. It is the intent of ITU-T Q.711, ITU-T Q.712, ITU-T Q.713 and ITU-T Q.714 to specify protocol entities which perform the functi
24、ons according to the SCCP of the Signalling System No. 7. These protocol entities conform at their lower boundary to the upper boundary conditions specified in ITU-T Q.704 or ITU-T Q.2210 for use of the service offered by the underlying layers. The SCCP making use of the services of the MTP, as spec
25、ified in ITU-T Q.2210, provides the connectionless network service as specified in this Recommendation. A connection-oriented network service can only use the services which are common to ITU-T Q.2210 and ITU-T Q.704 for the MTP. ITU-T Q.715 gives guidance on a number of specific issues related to t
26、he incorporation of SCCP in actual networks. These guidelines are in their entirety informal and do not specify any requirement. The SCCP congestion control procedures may be subject to improvement pending further analysis of the impact of these procedures in different network scenarios and based on
27、 the results of operational experience. The overall objectives of the signalling connection control part are to provide the means for: a) logical signalling connections within the Signalling System No. 7 network; b) a transfer capability for network service data units with or without the use of logi
28、cal signalling connections. Functions of the SCCP are also used for the transfer of circuit-related and call-related signalling information of the ISDN user part with or without setup of end-to-end logical signalling connections. These functions are described in ITU-T Q.714 and ITU-T Q.730. Figure 1
29、 illustrates the embedding of the SCCP within the Signalling System No. 7. 2 ITU-T Q.711 (03/2001) T1157170-93User parttype BOther SCCPuserUser parttype ASCCPMTPNOTE Interface using the signals as defined in 6.1.1.3.3, i.e. for the connection-orientednetwork service.The ISDN-UP that provides end-to-
30、end signalling as defined in ITU-T Q.730 isa type A user part.(Note)Figure 1/Q.711 Functional diagram for the SCCP in Signalling System No. 7 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this
31、Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other r
32、eferences listed below. A list of the currently valid ITU-T Recommendations is regularly published. The references contained in 2.1 and 2.2 contain the reference list for ITU-T Q.711, ITU-T Q.712, ITU-T Q.713 and ITU-T Q.714. 2.1 Normative references CCITT Blue Book, Fascicle VI.7, Glossary (1988),
33、Glossary of terms used in Signalling System No. 7. ITU-T Q.701 (1993), Functional description of the message transfer part (MTP) of Signalling System No. 7. ITU-T Q.704 (1996), Signalling network functions and messages. ITU-T Q.712 (1996), Definition and function of signalling connection control par
34、t messages. ITU-T Q.713 (2001), Signalling connection control part formats and codes. ITU-T Q.714 (1996), Signalling connection control part procedures. ITU-T Q.2210 (1996), Message transfer part level 3 functions and messages using the services of ITU-T Recommendation Q.2140. ITU-T X.210 (1993), In
35、formation technology Open Systems Interconnection Basic Reference Model: Conventions for the definition of OSI services. 2.2 Informative references ITU-T Q.700 (1993), Introduction to CCITT Signalling System No. 7. ITU-T Q.706 (1993), Message transfer part signalling performance. ITU-T Q.711 (03/200
36、1) 3 ITU-T Q.715 (1996), Signalling connection control part user guide. ITU-T Q.716 (1993), Signalling System No. 7 Signalling Connection Control Part (SCCP) performance. ITU-T Q.1400 (1993), Architecture framework for the development of signalling and OA services assumed from the MTP; functions of
37、the SCCP. The functions of the SCCP are performed by means of the SCCP protocol between two systems that provide the NSP service to the upper layers. The service interfaces to the upper layers and to the MTP are described by means of primitives and parameters, as recommended in ITU-T X.200. Figure 2
38、 illustrates the relationship between the SCCP protocol specification and the definition of adjacent services. ITU-T Q.711 (03/2001) 5 T1157180-93SCCPprotocolspecificationNetworkservicedefinitionMTPservicedefinitionReference to aimsReference to assumptionsFigure 2/Q.711 Relationship between the SCCP
39、 protocol specification and the definition of adjacent services 5.2 Primitives Primitives define the information flow associated with the services requested of the SCCP and of the MTP (see Figure 3). T1157190-93UpperlayersN-Service primitivesSCCP-SAPServices of the SCCPService accesspoints (SAP)Sign
40、allingconnection controlpartServices of the MTPMessagetransfer partMTP-SAPMTP-Service primitivesService primitivesFigure 3/Q.711 Service primitives This diagram shows the points at which service primitives are invoked. It is not intended to constrain the architecture. For the architectural considera
41、tions, some information is provided in ITU-T Q.1400. 5.3 Peer-to-peer communication Exchange of information between two peers of the SCCP is performed by means of a protocol. The protocol is a set of rules and formats by which the control information (and user data) is exchanged between the two peer
42、s. The protocol caters for: the set-up of logical signalling connection; the release of logical signalling connections; the transfer of data with or without logical signalling connections. 6 ITU-T Q.711 (03/2001) 5.4 Model of the connection-oriented network service A signalling connection is modelle
43、d in the abstract by a pair of queues. The protocol elements are objects on that queue added by the origination SCCP user and removed by the destination SCCP user. Each queue represents a flow control function. Figure 4 illustrates the modes described above. T1157200-93User of thenetworkserviceUser
44、of thenetworkserviceQueue B to AQueue A to BNode A Node BFigure 4/Q.711 Model for the internode communication with the SCCP (connection-oriented services) 5.5 Model of the connectionless network service This service definition uses the abstract model for a layer service defined in clause 5/X.210. Th
45、e model defines the interactions between the user and the provider of the connectionless network service. These interactions take place at the two SCCP-SAPs (see Figure 5). T1178310-96User of thenetworkserviceUser of thenetworkserviceNode X Node YVirtual transient association between A and BService
46、providerSCCP-SAP A SCCP-SAP BFigure 5/Q.711 Model of a network connectionless transmission A defining characteristic of network-connectionless transmission is the independent nature of each invocation of the connectionless network service. This basic service has been enhanced to provide sequence int
47、egrity between SDUs (see protocol class 1 service). The connectionless network service, as provided between SCCP-SAPs, can be modelled in the abstract as a virtual transient association between the SCCP-SAPs (see Note). NOTE This model is intended solely to describe the appearance of the connectionl
48、ess-mode network service to the SCCP users. It is not intended to be a model of the internal operation of the service provider in providing the connectionless network service. ITU-T Q.711 (03/2001) 7 Only one type of object, the Unitdata, can be exchanged between the users of the service. This relat
49、ionship is illustrated in Figure 5. 5.6 Contents of the Q.71X-series Recommendations ITU-T Q.711 contains a general description of the services provided by the MTP, the services provided by the SCCP and the functions within the SCCP. ITU-T Q.712 defines the function of the messages, the set of protocol elements and their embedding into messages. ITU-T Q.713 describes the formats and codes used for the SCCP messages. ITU-T Q.714 is a detailed description of the SCCP procedures as a protocol specification. IT
