1、INTERNATIONAL TELECOMMUNICATION UN ION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU . . Q.2939.1 SERIES Q: SWITCHING AND SIGNALLING Broadband ISDN - B-ISDN application protocols for access signal I i ng (09/97) Digital Subscriber Signalling System No. 2 - Application of DSS 2 service-relate
2、d information elements by equipment supporting B-ISDN services ITU-T Recommendation Q.2939.1 (Previously CCITT Recommendation) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING FUNCTIONS AND INFOR
3、MATION FLOWS FOR SERVICES IN THE ISDN CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SIGNALLING SYSTEM RI SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING
4、 SY S.TEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. I PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK BROADBAND ISDN General aspects Signalling ATM adaptation layer (SAAL) Signalling network protocols Common aspects
5、of B-ISDN application protocols for access signalling and network signalling and interworking Q. 1-Q.3 Q.4-Q.59 Q.60-Q.99 Q. 100-Q. 1 19 Q. 120-4.249 4.250-4.309 Q.3 10-4.399 Q.400-Q.499 Q .500-Q.599 Q.600-Q.699 Q .700-Q.849 Q.85O-Q.999 Q. 1000-Q. 1099 Q. 1 100-Q. 1 199 Q.1200-Q.1999 Q.2000-Q.2999 Q
6、.2000-Q.2099 Q.2 100-Q.2199 Q.2200-Q.2299 Q.2600-Q.2699 II B-ISDN application protocois for the network signalling O .2700-O ,2899 -_ - - . B-ISDN application protocols for access signalling Q.290eQ.2999 - For further details, please refer !o ITU-T List ofRecommendations. ITU-T RECOMMENDATION Q.2939
7、.1 DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 2 - APPLICATION OF DSS 2 SERVICE-RELATED INFORMATION ELEMENTS BY EQUIPEMENT SUPPORTING B-ISDN SERVICES Summary This Recommendation provides supplementary information on the usage of the service-related information elements (B-BC, AAL parameters, B-HLI, B-L
8、LI, N-BC, N-HLC, N-LLC) for individual B-ISDN services. It considers the services as they are specified for public B-ISDN. It does not specify additional codings required to support services by private networks. This Recommendation is Parti of Recommendation 4.2939. The coding for the parameters whi
9、ch are defined in Recommendation 4.2931 (1996) are specified in this part, while the coding for the additional traffic parameters which are defined in Recommendation Q.2961 (1996) are expected to be specified in the subsequent publication of additional parts of Recommendation 4.2939. Source ITU-T Re
10、commendation 4.2939.1 was prepared by ITU-T Study Group i 1 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 12th of September 1997. Recommendation Q.2939.1 (09/97) I FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the fie
11、ld of telecommuni- cations. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The 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 bas
12、is. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the pro
13、cedure 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 conciseness to indicate both
14、 a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU 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 takes no position concerning
15、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 had not received notice of intellectual property, protected by pate
16、nts, 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 1998 Ail rights reserved. No part of this publication may be reproduced or ut
17、ilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation Q.2939.1 (09/97) CONTENTS 7 8 Introduction Scope and objective . References . Abbreviations General principles applicable to all services
18、Impact of intenvorking situations 6.1 Incoming calls originated in non-ISDNs 6.2 N-BC and N-LLC application guidelines for emulated N-ISDN services Request and recognition of a basic B-ISDN service 7.1 Request and recognition of a broadband bearer service . Application of the E-BC, N-BC, N-HLC, N-LL
19、C, ATM traffic descriptor, QS parameter and AAL parameter information elements for emulated N-ISDN services . . Page 1 1 2 2 2 3 3 3 3 3 6 Recommendation Q.2939.1 (09/97) iii Recommendation 4.2939.1 DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 2 - APPLICATION OF DSS 2 SERVICE-RELATED INFORMATION ELEMENT
20、S BY EQUIPEMENT SUPPORTING B-ISDN SERVICES (Geneva, 1997) 1 Introduction This Recommendation specifies the service-related coding of the information elements to be used by terminals supporting the B-CSDN telecommunication services identified in the Recommendations in Study Group 1 and operating in t
21、he demand mode. It is based on Recommendation Q.293 1 i including its relevant Annexes B and E. For each service it is specified which field values the calling user is requested to send and which field values the called user could expect to receive in a pure B-ISDN environment (clause 7). Clause 8 s
22、pecifies the codings to be used in the case that an emulated N-ISDN service is requested. The exact information elements and their bit patterns correlated with the named field values can be found in the following subclauses of Recommendation Q.293 1 i: - in 4.5.7 as for the broadband bearer capabili
23、ty information element; - in 4.5.8 as for the broadband high layer information element; - in 4.5.9 as for the broadband low layer information element;. - - - - in 4.5.5 as for the ATM adaptation layer parameter information element; in 4.5.6 as for the ATM traffic descriptor information element; in 4
24、.5.18 as for the quality of service parameter information element; and in 4.5.24 as for the OAM traffic descriptor information element. Generally, the above-mentioned information elements serve the following purposes. At the calling side, the network shall check that the bearer service requested by
25、the calling user in the broadband bearer capability information element matches with the broadband bearer service provided to that user by the network (see Annex BlQ.293 1 i). At the called side, the called user performs network-to-user compatibility checking based on the content of the B-BC, QOS pa
26、rameter, ATM traffic descriptor and OAM traffic descriptor information elements. In addition, the user performs user-to-user compatibility checking based on the content of the AAL parameter, B-HLI and B-LLI information elements (see Annex BlQ.2931 i). 2 Scope and objective This Recommendation provid
27、es supplementary information on the usage of the compatibility information elements for individual B-ISDN services. It considers the services as they are specified for public B-ISDN. It does not specify additional codings required to support services by private networks. This Recommendation is Part
28、1 of Recommendation Q.2939. The codings for the parameters which are defined in Recommendation 4.293 1 i 1 (SCS 1) are specified in this part and the codings for the additional traffic parameters which are defined in Recommendation Q.2961 will be specified in the following parts of this Recommendati
29、on. The services currently covered in this Recommendation may require to be enhanced when new services are defined and/or when the functionality of the networks and terminal equipment has progressed. Recommendation 4.2939.1 (09l97) 1 The specific objective of this Recommendation is to provide guidan
30、ce on the correct usage of DSS 2 codepoints to the different ITU-T Study Groups dealing with services, B-ISDN terminals and terminal adapters. This Recommendation shall help to assure interoperability of terminals supporting the same telecommunication service and shall enable terminals to operate on
31、 different public B-ISDNs. The typical codings specified in clause 7 shall be supported by all users and networks supporting the corresponding service. Other variants of these codings may be supported in addition, however, these variants might not provide for worldwide interoperability and might not
32、 guarantee terminal interchangeability. Finally, clause 8 presents codings when emulated N-ISDN services are requested. 3 References The following IT-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the
33、time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed be
34、low. A list of the currently valid IT-T Recommendations is regularly published. i . IT-T Recommendation 4.293 1 (1995), Digital Subscriber Signalling System No. 2 (DSS 2) - User-Network Interface (UNI) layer 3 specification for basic calllconnection control. 2 CCITT Recommendation F.8 1 1 ( 1992), B
35、roadband connection-oriented bearer service. 3 ITU-T Recommendation Q.939 (1 993), Typical DSS 1 service indicator codings for ISDN telecommunications services. 4 Abbreviations The abbreviations of Annex 514.2931 i apply. 5 General principles applicable to all services For all services the following
36、 principles apply: i) The AAL information element for BCOB-X is transferred transparently through a B-ISDN between the calling entity and the addressed entity. However, dependent on the charging principles applied (e.g. for narrow-band ISDN interworking), some networks may perform checks on the leng
37、th of,the AAL information elements. For BCOB-A and BCOB-B, networks can act upon the AAL information element. The broadband high layer information element is transferred transparently through a B-ISDN between the calling entity and the addressed entity. However, some networks may check its content,
38、e.g. to associate a supplementary service to a teleservice. 2) 3) When bearer services are specified, the B-HLI information element will normally not be present unless it is used to support high layer applications. The broadband low layer information element is transferred transparently through a B-
39、ISDN between the calling entity and the addressed entity. However, dependent on the charging principles applied, some networks may perform checks on the length of the B-LLI information element. The narrow-band low layer compatibility information element is transferred transparently through a B-ISDN
40、between the calling entity and the addressed entity. However, dependent on the charging principles applied, some networks may perform checks on the length of the N-LLC information. The narrow-band high layer compatibility information element is transferred transparently through a B-ISDN between the
41、calling entity and the addressed entity. However, some networks may check its content, e.g. to associate a supplementary service to a teleservice. The coding examples consider the general case. 4) 5) 6) 7) 2 Recommendation Q.2939.1 (09/97) Conventions applied for the presentation of the coding examp
42、les: i) Octets 1-4 of the compatibility information elements, indicating the information element identifier, coding standard, information element instruction field and length respectively, are omitted from the considerations and therefore not shown in the examples. A dashed line (-) instead of a fie
43、ld value indicates: a) b) Field values in brackets ( ) may or may not be included at the calling side and therefore may or may not be present at the called side. 2) at the calling side: this field is not included in the information element; at the called side: this field is not present. 3) Informati
44、on element field Bearer class 6 Impact of interworking situations l Field value BCOB-A or BCOB-C or BCOB-X 6.1 Incoming calls originated in non-ISDNs Traffic type Ti mi ng requirements Susceptibility to clipping User plane connection configuration In the case of an incoming call originated in a non-
45、ISDN, N-HLC and N-LLC information elements will be absent, and interworking with a non-ISDN is shown by the presence of the progress indicator information element. When this occurs, the terminal shall accept the incoming call according to Annex B/Q.293 1 i, i.e. it shall regard the compatibility as
46、successful if it is compatible with the included information, which as a minimum will be in addition to the information elements listed in B.3.2IQ.293 1 i and B.3.3/Q.293 i 11 the narrow-band bearer capability information element. No indication or constant bit rate or variable bit rate No indication
47、 or end-to-end timing required or end- to-end timing not required Not susceptible or susceptible Point-to-point or point-to-multipoint 6.2 N-BC and N-LLC application guidelines for emulated N-ISDN services The N-BC and N-LLC information elements shall be used in accordance with the BC and LLC applic
48、ation guidelines described in 6.21Q.939 3. 7 Request and recognition of a basic B-ISDN service 7.1 Request and recognition of a broadband bearer service 7.1.1 Request and recognition of a general broadband connection-oriented bearer service (Recommendation F.811 121) 7.1.1.1 a) B-BC information elem
49、ent coding: Request by a calling terminal equipment , Octet I Y- 5a (Note) I I NOTE - This octet may only be present if bearer class “X” is indicated in octet 5. b) The ATM traffic descriptor information element and quality of service information element are set according to the user requirements. The AAL parameters information element, B-HLI information element and B-LLI information element are optional. c) Recommendation Q.2939.1 (09/97) 3 7.1.1.2 a) B-BC information element coding: Compatibility at the called terminal equipment Octet 5 Information
