1、INTERNATIONAL TELECOMMUNICATION UN ION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES Q: SWITCHING AND SIGNALLING Q.714 Specifications of Signalling System No. 7 - Sigr connection control part (SCCP) (05/2001) alling Signalling connection control part procedures ITU-T Recommendation Q.
2、714 (Formerly CCITT Recommendation) ITU-T Q-SERES RECOMMENDATIONS SWITCHING AND SIGNALLING Message transfer part (MTP) Q.701-Q.709 Telephone user part (TUP) 4.720-4.729 ISDN supplementary services 4.7304.739 Data user part Q.740-Q.749 Signalling System No. 7 management 4.750-4.759 ISDN user part 4.7
3、60-4.769 Transaction capabilities application part 4.770-4.779 Test specification 4.780-4.799 43 INTERFACE Q.SOO-Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850-Q.999 PUBLIC LAND MOBILE NETWORK Q.1000-Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100-Q.1199 INTELLIGENT NETWORK Q. 1200-
4、4.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 4.1700-Q.1799 , BROADBAND ISDN Q.200O-Q.2999 SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No.
5、6 SPECIFICATIONS OF SIGNALLING SYSTEM R1 SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS General Q. 14.3 4.4-4.59 4.60
6、-4.99 Q.lOO-Q.119 Q.250-Q.309 4.3 104.399 Q.400-Q.499 Q.50O-Q.599 4.6004.699 4.700-4.799 4.700 Q. 120-4.249 For further details, please refer to the list of ITU-T Recommendations. ITU-T Recommendation 4.714 Signalling connection control part procedures Summary This Recommendation describes the proce
7、dures performed by the Signalling Connection Control Part (SCCP) of Signalling System No. 7 to provide connection-oriented and connectionless network services, as well as SCCP management services as defined in ITU-T 4.71 1. These procedures make use of the messages and information elements defined i
8、n ITU-T 4.7 12, whose formatting and coding aspects are specified in ITU-T 4.713. Source ITU-T Recommendation 4.714 was revised by ITU-T Study Group 11 (2001-2004) and approved under the WTSA Resolution 1 procedure on 25 May 2001. ITU-T 4.714 (05/2001) i FOREWORD The International Telecommunication
9、Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization 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 t
10、o standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which 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 Recommendation
11、s is covered by the procedure laid down in WTSA Resolution 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 conciseness
12、 to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU 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 c
13、oncerning 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, ITU had not received notice of intellectual property, protected b
14、y 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 2002 All rights reserved. No part of this publication may be reproduced
15、 or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. 11 ITU-T 4.714 (05/2001) CONTENTS Page 1 1.1 1.2 1.3 1.4 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Introduction . General characteristics of signalling connection con
16、trol procedures . 1.1.1 Purpose 1.1.2 Protocol classes 1.1.3 Signalling connections . 1.1.4 Compatibility and handling of unrecognized information Overview of procedures for connection-oriented services . 1.2.1 Connection establishment 1.2.2 Data transfer 1.2.3 Connection release . Overview of proce
17、dures for connectionless services 1.3.1 General . 1.3.2 Segmentatiodreassembly Structure of the SCCP and contents of this Recommendation . Addressing and routing . SCCP addressing principles SCCP routing principles . 2.2.1 2.2.2 Receipt of SCCP message transferred by the MTP . Messages passed from c
18、onnection-oriented or connectionless control to SCCP routing control . SCCP routing procedures 2.3.1 Receipt of SCCP messages transferred by the MTP . 2.3.2 routing control . Global title translation 2.4.1 General characteristics of the GTT 2.4.2 Terminology definitions Messages from connectionless
19、or connection-oriented control to SCCP 2.4.3 2.4.4 2.4.5 Input of the GTT function . Output of the GTT function . Global title translation function . . Compatibility test Traffic limitation mechanism 2.6.1 General . 2.6.2 Importance of a message . 2.6.3 Handling of messages to a congested node . Cal
20、ling party address treatment 2.7.1 Address indicator . . 1 1 1 1 2 3 3 3 4 4 5 5 5 5 10 12 12 12 13 14 15 17 17 17 17 18 19 19 . ITU-T 4.714 (05/2001) 111 2.7.2 Calling party address in the international network 2.7.3 Routing indicator . 2.7.4 Screening . .i Inclusion of OPC in the calling party add
21、ress . 2.8 Routing failures . No translation for an address of such nature . No translation for this specific address 2.8.3 MTP/SCCP/subsystem failure . 2.8.4 MTP/SCCP/subsystem congestion 2.8.5 Unequipped user 2.8.6 Hop counter violation 2.7.5 2.8.1 2.8.2 3 Connection-oriented procedures . 3.1 Conn
22、ection establishment . 3.1.1 General . 3.1.2 Local reference numbers . 3.1.3 Negotiation procedures Actions at the originating node Actions at a relay node with coupling . Actions at the destination node 3.2 Connection refusal Actions at node initiating connection refusal 3.1.4 3.1.5 3.1.6 3.2.1 3.2
23、.2 3.2.3 Actions at a relay node not initiating connection refusal Actions at the originating node not initiating connection refusal 3.3 Connection release 3.3.1 General . 3.3.2 Frozen reference 3.3.3 3.3.4 Actions at a relay node. 3.3.5 Actions at an end node . initiating connection release Actions
24、 at an end node not initiating connection release 3.4 Inactivity control . 3.5 Data transfer 3.5.1 General . 3.5.2 Flow control . 3.5.3 Segmenting and reassembly 3.6 Expedited data transfer . 3.6.1 General . 3.6.2 3.6.3 3.6.4 . Actions at the originating node Actions at a relay node Actions at the d
25、estination node Page 19 19 19 20 21 22 22 22 23 23 23 23 23 23 24 24 25 26 28 28 29 29 30 30 30 30 30 31 32 32 32 32 33 35 36 36 36 36 36 iv ITU-T 4.714 (092001) 3.7 3.8 4 4.1 4.2 4.3 5 5.1 5.2 5.3 Reset 3.7.1 General . 3.7.2 3.7.3 3.7.4 3.7.5 Restart . 3.8.1 General . 3.8.2 Actions at the recovered
26、 node . 3.8.3 Actions at the non-failed far end node . 3.8.4 Syntax error . 3.8.5 Action tables 3.8.6 Actions upon the reception of an ERR message Action at an end node initiating the reset procedure . Actions at an end node not initiating the reset procedure Handling of messages during the reset pr
27、ocedures . Actions at a relay node Connectionless procedures . 4.1 . 1 Segmentationheassembly Message return procedure . SCCP management procedures . Signalling point status management . Data transfer 4.1.2 Message change . Syntax error . General 5.2.1 General . 5.2.2 Signalling point prohibited 5.2
28、.3 Signalling point allowed 5.2.4 Signalling point congested . Local MTP network unavailability SCCP reports of SCCP and nodal congestion . Subsystem status management 5.3.2 Subsystem prohibited 5.3.3 Subsystem allowed 5.3.4 Subsystem status test . 5.3.5 Coordinated state change . 5.3.6 Local broadc
29、ast 5.3.7 Broadcast . 5.2.5 5.2.6 5.2.7 5.2.8 Local MTP network availability Inter- and Intra- SCCP management congestion reports procedure 5.3.1 General . ITU-T 4.714 (05/2001) Page 36 36 37 37 38 39 39 39 39 39 41 41 41 41 42 43 47 48 48 49 49 51 51 51 52 52 53 53 54 55 55 55 55 56 56 57 58 59 V 5
30、.4 Local SCCP restart Annex A . State diagrams for the signalling connection control part of Signalling System No . 7 . A . 1 Introduction . A.2 Symbol definition of the state diagrams at the message interface A.3 Symbol definition of the state diagrams . Annex B . Action tables for the SCOC . B . 1
31、 Introduction . B.2 Symbol definition of the action tables B.3 Table of contents . Annex C . State Transition Diagrams (STD) for the signalling connection control part of Signalling Systems No . 7 C.l General C.2 Drafting conventions . C.3 Figures C.4 Abbreviations and timers Annex D . State transit
32、ion diagrams (STD) for SCCP management control D.l General D.2 Drafting conventions . D.3 Figures D.4 Abbreviations and timers Page 60 61 61 61 62 64 64 64 65 69 69 70 70 71 136 136 137 137 137 vi ITU-T 4.714 (092001) ITU-T Recommendation 4.714 Signalling connection control part procedures 1 Introdu
33、ction 1.1 General characteristics of signalling connection control procedures 1.1.1 Purpose This Recommendation describes the procedures performed by the Signalling Connection Control Part (SCCP) of Signalling System No. 7 to provide connection-oriented and connectionless network services, as well a
34、s SCCP management services as defined in ITU-T 4.71 1. These procedures make use of the messages and information elements defined in ITU-T 4.712, whose formatting and coding aspects are specified in ITU-T 4.713. 1.1.2 Protocol classes The protocol used by the SCCP to provide network services is subd
35、ivided into four protocol classes, defined as follows: - - - - The connectionless protocol classes provide those capabilities that are necessary to transfer one Network Service Data Unit (NSDU) in the “data“ field of an XUDT, LUDT or UDT message. When one connectionless message is not sufficient to
36、convey the user data contained in one NSDU making use of MTP services provided by an MTP-SAP that supports a maximum MTP SDU size of 272 octets including the MTP routing label, a segmentingheassembly function for protocol classes O and 1 is provided. In this case, the SCCP at the originating node or
37、 in a relay node provides segmentation of the information into multiple segments prior to transfer in the “data“ field of XUDT (or as a network option LUDT) messages. At the destination node, the NSDU is reassembled. If it is certain that only MTP services according to ITU-T 4.2210 are used in the n
38、etwork, then no segmentation information is needed. The connection-oriented protocol classes (protocol classes 2 and 3) provide the means to set up signalling connections in order to exchange a number of related NSDUs. The connection-oriented protocol classes also provide a segmenting and reassembli
39、ng capability. If an NSDU is longer than 255 octets, it is split into multiple segments at the originating node, prior to transfer in the “data“ field of DT messages. Each segment is less than or equal to 255 octets. At the destination node, the NSDU is reassembled. NOTE - Enhancements to protocol c
40、lasses 2 and 3 for the SCCP capable of supporting long messages are for further study. Class O: Basic connectionless class; Class 1 : Sequenced connectionless class; Class 2: Basic connection-oriented class; Class 3 : Flow control connection-oriented class. 1.1.2.1 Protocol class O Network Service D
41、ata Units passed by higher layers to the SCCP in the originating node are delivered by the SCCP to higher layers in the destination node. They are transferred independently of each other. Therefore, they may be delivered to the SCCP user out-of-sequence. Thus, this protocol class corresponds to a pu
42、re connectionless network service. ITU-T 4.714 (OY2001) 1 1.1.2.2 Protocol class 1 In protocol class 1, the features of class O are complemented by an additional feature (i.e. the sequence control parameter contained in the N-UNITDATA request primitive) which allows the higher layer to indicate to t
43、he SCCP that a given stream of NSDUs shall be delivered in-sequence. The Signalling Link Selection (SLS) parameter in the MTP-TRANSFER request primitive is chosen by the originating SCCP based on the value of the sequence control parameter. The SLS shall be identical for a stream of NSDUs with the s
44、ame sequence control parameter. The MTP then encodes the Signalling Link Selection (SLS) field in the routing label of MTPmessages relating to such NSDUs, so that their sequence is, under normal conditions, maintained by the MTP and SCCP. With the above constraints, the SCCP and MTP together ensure
45、in-sequence delivery to the user. Thus, this protocol class corresponds to an enhanced connectionless service, where an additional in-sequence delivery feature is included. 1.1.2.3 Protocol class 2 In protocol class 2, bidirectional transfer of NSDUs between the user of the SCCP in the originating n
46、ode and the user of the SCCP in the destination node is performed by setting up a temporary or permanent signalling connection consisting of one or more connection sections. A number of signalling connections may be multiplexed onto the same signalling relation. Each signalling connection in such a
47、multiplexed stream is identified by using a pair of reference numbers, referred to as “local reference numbers“. Messages belonging to a given signalling connection shall contain the same value of the SLS field to ensure sequencing as described in 1.1.2.2. Thus, this protocol class corresponds to a
48、simple connection-oriented network service, where SCCP flow control and loss or mis-sequence detection are not provided. 1.1.2.4 Protocol class 3 In protocol class 3, the features of protocol class 2 are complemented by the inclusion of flow control, with its associated capability of expedited data
49、transfer. Moreover, an additional capability of detection of message loss or mis-sequencing is included for each connection section; in such a circumstance, the signalling connection is reset and a corresponding notification is given by the SCCP to the higher layers. 1.1.3 Signalling connections In all connection-oriented protocol classes, a signalling connection between the nodes of origin and destination may consist of: - - a single connection section; or a number of connection sections in tandem, which may belong to different interconnected signalling networks. In the former case, the ori
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