1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.1912.1 (07200 1 ) SERIES Q: SWITCHING AND SIGNALLING Specifications of signalling related to Bearer Independent Call Control (BICC) Interworking between Signalling System No. 7 ISDN user part and the Bearer
2、 Independent Call Control protocol ITU-T Recommendation Q. 191 2.1 (Formerly CCITT Recommendation) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICATIONS OF SIGNALLING SYSTEMS No.
3、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 Q3 INTERFACE DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBIL
4、E NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) BROADBAND ISDN INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS SIGNALLING REQUIREMENTS AND PROTOCOLS
5、 FOR IMT-2000 Q. 1-Q.3 Q .4-Q, 5 9 4.60-4.99 Q. 100-Q. 1 19 Q. 120-4.249 4.250-4.309 4.400-4.499 Q.600-Q.699 4.3 10-4.399 Q.500-Q.599 Q.700-Q.799 Q.800-Q.849 Q.850-Q.999 Q.1000-Q.1099 Q.1100-Q. 1199 Q.1200-4.1699 Q.1700-Q.1799 Q.1900-4.1999 Q.2000-Q.2999 For further details, please refer to the list
6、 of ITU-T Recommendations. ITU-T Recommendation Q.1912.1 Interworking between Signalling System No. 7 ISDN user part and the Bearer Independent Call Control protocol Summary This Recommendation defines the signalling interworking between the Bearer Independent Call Control (BICC) protocol and the IS
7、DN User Part (ISUP) of Signalling System No. 7. Source ITU-T Recommendation Q.1912.1 was prepared by ITU-T Study Group 1 1 (2001 -2004) and approved under the WTSA Resolution 1 procedure on 2 July 2001. ITU-T Q.1912.1 (07/2002) 1 FOREWORD The International Telecommunication Union (ITU) is the United
8、 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 to standardizing telecommu
9、nications 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 Recommendations is covered by the proce
10、dure 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 to indicate both a telec
11、ommunication 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 concerning the evidence, v
12、alidity 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 by patents, which may be r
13、equired 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 or utilized in any form
14、or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. 11 ITU-T 4.1912.1 (07/2001) CONTENTS Page 1 2 3 4 5 6 6.1 6.2 6.3 Scope . References . Definitions Abbreviations Conventions Interworking with ISUP at an ISN General Incoming ISUP
15、. outgoing BICC (Incoming ISN) 6.2.1 Successful basic call Set-up . 6.2.2 Call release Incoming BICC. outgoing ISUP (Outgoing ISN) . 6.3.1 Successful call Set-up . 6.3.2 Call release ITU-T Q.1912.1 (07/2002) 1 1 2 2 3 3 3 . 111 ITU-T Recommendation 4.1912.1 * : CSF-N -b EHTl caiibearer: BICC control
16、 Interworking between Signalling System No. 7 ISDN user part and the Bearer Independent Call Control protocol 1 Scope This Recommendation defines the signalling intenvorking between the Bearer Independent Call Control (BICC) protocol and the ISDN User Part (ISUP) of Signalling System No. 7. BICC is
17、the protocol defined in ITU-T Q.1902.1. It is the call control protocol used between “Serving Nodes“ in a network that uses separate call and bearer control protocols. An Interface Serving Node (ISN) is a node that provides an interface to circuit switched networks. ISUP is the protocol defined in I
18、TU-T 4.761. It is the combined call and bearer control protocol used to support narrow-band ISDN services in a circuit switched network. The intenvorking between BICC and ISUP takes place in the CSF at an ISN. The scope of this Recommendation is thus as shown in Figure 1. ISUP ISN 4 BICC Bearer cont
19、rol _, SCN network Network using separate call and bearer signalling T11111870O1 Figure UQ.1912.1- Scope of this Recommendation 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation
20、. 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 references list
21、ed below. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T 4.1912.1 (07/2002) 1 ITU-T 4.761 (1999), Signalling System No. 7 - ISDN user part functional description. ITU-T 4.762 (1 999), Signalling System No. 7 - ISDN user part general functions of messages and signal
22、s. ITU-T 4.763 (1 999), Signalling System No. 7 - ISDN user part formats and codes. ITU-T 4.764 (1 999), Signalling System No. 7 - ISDN user part signallingprocedures. ITU-T 4.730 (1999), ISDN user part supplementary services. ITU-T Q. 1902.1 (2001), Bearer Independent Call Control protocol (BICC) (
23、Capability set 2): Functional description. ITU-T Q. 1902.2 (2001), Bearer Independent Call Control protocol (BICC) (Capability set 2) and Signalling System No. 7 ISDN user part: General functions of messages and parameters. ITU-T Q. 1902.3 (2001), Bearer Independent Call Control protocol (BICC) (Cap
24、ability set 2) and Signalling System No. 7 ISDN user part: Formats and codes. ITU-T Q. 1902.4 (2001), Bearer Independent Call Control protocol (BICC) (Capability set 2): Basic call procedures. ITU-T 4.767 (1991), Application of the ISDN user part of CCITTSignalling System No. 7 for international ISD
25、N interconnections. Definitions For the BICC specific terminology, the reader is referred to ITU-T Q.1902.1 6. 4 Abbreviations This Recommendation uses the following abbreviations: ACM BCF BCF-N BICC BIWF COT CPG CSF CSF-N IAM ISDN ISN ISUP PSTN REL RLC 3 Address Complete Message Bearer Control Func
26、tion Bearer Control Nodal Function Bearer Independent Call Control Bearer Interworking Function Continuity message Call Progress message Call Service Function Call Service Nodal Function Initial Address Message Integrated Services Digital Network Interface Serving Node ISDN User Part Public Switched
27、 Telephone Network Release message Release Complete message Li ITU-T Q.1912.1 (07/2001) SCN SN 5 1) 2) 3) 6 6.1 Switched Circuit Network Serving Node Conventions The name of each element of the following classes of terms is capitalized: indicators; parameters; information elements; messages. Example
28、s: Called Party Number parameter, Initial Address message. The definition of a parameter value is written in italics and is put between quotation marks. Example: Nature of Address value O00001 1 - “national (signijkant) number“. All message names are BICC messages unless explicitly stated otherwise.
29、 Example: The “IAM message“ is the IAM message in BICC, whereas an IAM message in ISUP is referred to as an “ISUP IAM message“. Interworking with ISUP at an ISN General The protocol at the ISUP interface shall be according to the ISUP Recommendations, 4.761 i. The protocol at the BICC interface shal
30、l be according to the BICC Recommendations, Q. 1902.1 6. Transfer of signalling information between the two signalling interfaces shall be done as was an ISUP intermediate exchange. Where the signalling information defined for ISUP and for BICC, are identical a one-to-one mapping is performed (unles
31、s explicitly specified to the contrary in this Recommendation). BICC includes a Compatibility procedure in ITU-T 4.1902.4 9 identical to the Compatibility procedure defined for ISUP in ITU-T Q.764 4. The CSF may act as a Type A or Type B exchange for the purposes of this Compatibility procedure. see
32、 ITU-T see ITU-T if the CSF The following subclauses detail the only exceptions to the above statements. 6.2 Incoming ISUP, outgoing BICC (Incoming ISN) 6.2.1 Successful basic call Set-up 6.2.1.1 Forward address signalling Incoming ISUP (as in 2.UQ.764 4) and outgoing BICC (as in 7.2 and 7.3Q.1902.4
33、 6) procedures apply with the following exception: When sending the IAM the Continuity indicator in the Nature of Connection Indicators parameter is set according to 4.764 4 procedures. (Either COT to be expected“ or “no COT to be expected“ can be sent.) ITU-T Q.1912.1(07/2002) 3 6.2.1.2 Continuity
34、message The incoming ISUP Continuity check procedures in ITU-T Q.764 4 apply. Clause 7.6.1/Q.1902.4 6 is replaced by: The Continuity message, with the Continuity Indicators parameter set to “continuity“ is sent when an ISUP COT with the Continuity Indicators parameter set to %ontinuity check success
35、fu2“ is received from ISUP, according to ITU-T 4.764 4 intermediate exchange procedures. 6.2.1.3 The bearer path shall be connected in both directions when both of the following conditions are satisfied: Through connection of the bearer path a the BICC Outgoing bearer Set-up procedure (7.4/4.1902.4
36、6) is successfully completed; if the ISUP continuity check procedure is being performed, when conditions on the and incoming circuit allow, see 2.1 NQ.764 4. a In addition, if BICC is performing the “Per-call bearer Set-up in the forward direction“ Outgoing bearer Set-up procedure and the Connect Ty
37、pe is “notiJication not required“, the bearer path shall be connected in both directions when the Bearer Set-up request is sent (and any ISUP continuity check is complete). 6.2.1.4 Connection type allowing fallback 6.2.1.4.1 Actions in the forward direction 6.2.1.4.1.1 Succeeding network does have t
38、he capability of performing fallback The CSF will set up the call on a route according to the Transmission Medium Requirement parameter “64 kbith unrestrictedpreferred“ whenever available. If congestion on the route is encountered, and if there is no alternative route available supporting the connec
39、tion type allowing fallback, fallback procedures will be initiated according to 6.2.1.4.1.2. 6.2.1.4.1.2 Succeeding network does not have the capability of performing fallback In case there is no route available being capable of satisfying the connection type requirements of “64 kbith unrestricted p
40、referred“, the CSF will continue the call, discard the User Service Information Prime parameter, maintain the User Service Information parameter, change the Transmission Medium Requirement parameter in accordance with the fallback connection type contained in the Transmission Medium Requirement Prim
41、e parameter and then discard the Transmission Medium Requirement Prime parameter. 6.2.1.4.2 Actions in the backward direction 6.2.1.4.2.1 Succeeding network does have the capability of performing fallback The CSF will know that fallback has occurred by receiving the Transmission Medium Used paramete
42、r. This parameter indicates the fallback connection type. Appropriate actions to modify network resources, e.g. p-law/A-law conversion will be initiated. If echo control is required on the connection, appropriate procedures will be initiated (see 2.7/Q.764 4). 4 ITU-T 4.1912.1 (07/2001) 6.2.1.4.2.2
43、Succeeding network does not have the capability of performing fallback The CSF will include a Transmission Medium Used parameter (which has been set according to the fallback connection type indicated in the Transmission Medium Requirement Prime parameter) in the ACM or CPG indicating that fallback
44、has occurred for this call. Appropriate actions to modify network resources, e.g. p-law/A-law conversion will be initiated. If echo control is required on the connection, appropriate procedures will be initiated (see 2.7Q.764 4). 6.2.2 Call release On receipt of an ISUP REL from the preceding exchan
45、ge, the CSF immediately requests the disconnection of the internal bearer path and invokes the BICC Release sending procedure (11.5/Q.1902.4 6) towards the succeeding CSF. When the ISUP circuit is re-selectable, an ISUP RLC is returned to the preceding exchange. On receipt of a REL from the succeedi
46、ng CSF, the CSF invokes the BICC Release reception procedure and sends an ISUP REL to the preceding exchange. Timers T1 and T5 are started to ensure that a RLC is received from the preceding exchange (expiration of timers T1 and T5 is covered in 2.9.6/Q.764 4. 6.3 Incoming BICC, outgoing ISUP (Outgo
47、ing ISN) 6.3.1 Successful call set-up 6.3.1.1 Forward address signalling Incoming BICC (as in 7.2 and 7.3/Q.1902.4 6) and outgoing ISUP (as in 2.UQ.764 4) procedures apply, with the following clarifications and exceptions with regards to when ISUP IAM and Continuity messages are to be sent: Two case
48、s are supported: 1) 2) For the early IAM case (where the subsequent network supports the continuity check protocol) the ISUP IAM is sent when the incoming procedure decides that the call can be routed. The Continuity Check indicator in the Nature of Connection Indicators parameter is set to indicate
49、 %ontinuity check performed on previous circuit“, or %ontinuity required on this circuit“ may alternatively be sent if the continuity check is to be performed. The Continuity message, with the Continuity Indicators parameter set to %ontinuity check successful“ is sent when all the following conditions are satisfied: If the incoming IAM indicated “COT to be expected“, a Continuity message, with the Continuity Indicators parameter set to “continuity“ shall be received. One of the following events, which indicate successful completion of bearer
