1、 STD-ITU-T RECMN 8.27b4-L-ENGL L77b LiBb2591 Ob31338 70T INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.2964.1 SERIES Q: SWITCHING AND SIGNALLING Broadband ISDN - B-ISDN application protocols for access si g na I I i n g (07/96) Digital Subscriber Signa
2、lling System No. 2: Basic Look-Ahead ITU-T Recommendation Q.2964. I (Previously CCITT Recommendation) STDmITU-T RECMN Q-27bY.L-ENGL 177b LiAb2571 Ob31337 b4b ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE INTERNATIONAL AUTOMATIC AND SEMI-AUTOMA
3、TIC WORKING FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICATION 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 SYSTEMS SPECIF
4、ICATIONS OF SIGNALLING SYSTEM No. 7 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK BROADBAND ISDN General aspects ATM adaptation layer Signalling network protocols Common aspects of B-ISDN application protocols for
5、 access signalling and network signalling and interworking B-ISDN application protocols of the network CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS protocols for ac Q.1-Q.3 Q.4-Q.59 Q.60-Q.99 Q.100-Q.119 Q.120-Q.249 Q.250-Q.309 Q.310-Q.399 Q.400-Q.499 Q.500-Q.599 Q.600-Q.699 Q.700-Q.849 Q. 850-Q. 99
6、9 Q. 1 OOO-Q.l O99 Q.1100-Q.l I99 Q.1200-Q.1999 Q.2000-Q.2999 Q.2000-Q.2099 Q.2100-Q.2199 Q.2200-Q.2599 Q.2600-Q.2699 Q.2700-Q.2899 Q.290-Q.2999 For further details, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN Q*27b4=1-ENGL 177b 48b2571 Ob31340 3bd = ITU-T RECOMMENDATION Q.2964.1
7、DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 2: BASIC LOOK-AHEAD Summary This Recommendation defines the operation of the Digital Subscriber Signalling System No. 2 (DSS 2) for the handling of the Look-Ahead feature that may be supported, as a network option, prior to Basic call and connection control a
8、t the TB or at the coincident SB and TB reference point of the User to Network Interface of the Broadband Integrated Services Digital Network (B-ISDN). The Look-Ahead feature defined in this Recommendation enables the network to check whether compatible user equipment are connected to a user-network
9、 interface and whether they are free or busy. This feature can be used prior to an incoming call offering at the user-network interface. Source ITU-T Recommendation 4.2964.1 was prepared by ITU-T Study Group 11 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 9th of July
10、 1996. STD-ITU-T RECMN Q-25b4-1-ENGL 199b m 48b2591 Ob313111 2Tq M FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is
11、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 Conference (WTSC), which meets every four years, establishes the topics for study b
12、y 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 procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary
13、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 telecommunication administration and a recognized operating agency. r”IELLECTUAL PROPERTY RIGHTS The ITU draws attention to the po
14、ssibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside o
15、f the Recommendation development process. As of the date of approval of this Recommendation, the ITU hadhad not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the
16、latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1997 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 permission in writing
17、 from the ITU. Recommendation Q.2964.1 (07/96) 11 STD-ITU-T RECMN Q-27b4.1-ENGL 177b W 9Ab2591 Ob31392 130 CONTENTS Page 1.1 . Scope %.:. 1.2 References 1.3 Definitions 1.4 Abbreviations . 1.5 Description . 1.6 Operational requirements . 1.6.1 Provision and withdrawal 1.6.2 Requirements on the origi
18、nating network side 1.6.3 Requirements on the destination network side Primitive definitions and state definitions 1.7.1 Primitive definitions . 1.7.2 State definitions . 1.7 1.8 Coding requirements Coding rules ; . 1.8.1 Operations and errors 1 3.2 Signalling procedures at the coincident SB and TB
19、reference point 1.9.1 Normal operation . 1.9.2 Exceptional procedures . Procedures for intenvorking with private B-ISDNs . 1 . 1 O . 1 Originating interface 1 .1 0.2 Destination interface Interactions with other networks 1.1 1.1 Intenvorking with N-ISDNs 1.1 1.2 Intenvorking with non-ISDNs . 1.1 1.3
20、 Intenvorking with frame relay . 1.1 1.4 Intenvorking with PSPDNs . 1.12 Parameter values (timers) . 1.12.1 Timer at the coincident SB and TB reference point 1.12.2 Timer at the TB reference point . 1.13 Dynamic description (SDLs) 1.9 1.1 O . 1.1 1 Annex A . Network look-ahead indication . A.l Scope
21、 . A.2 Coding requirements 1 2 2 3 3 3 3 3 3 3 3 4 4 6 6 6 7 9 9 10 10 13 13 13 . Recommendation 4.2964.1 (07/96) 111 STD*ITU-T RECMN 8-27b4-1-ENGL 177b = 48b257L Ob31343 077 Page A.2.1 Messages . 13 A.2.2 1nformatio.n elements . 13 A.3 Signalling procedures at the TB reference point . 14 A.3.1 Norm
22、al operations . 14 A.3.2 Error handling procedures . 15 Appendix I - Information flows 15 iv Recommendation 4.2964.1 (07/96) Recommendation Q.2964.1 DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 2: BASIC LOOK-AHEAD (Geneva, 1996) 1.1 Scope This Recommendation specifies the basic look-ahead protocol for t
23、he Broadband Integrated Services Digital Network (B-ISDN) at the TB reference point or coincident S, and TB reference point (as defined in Recommendation 1,413 i) for the Digital Subscriber Signalling System No. 2 (DSS 2) protocol. This Recommendation does not speci the additional protocol requireme
24、nts where the feature is provided to the user via a telecommunications network that is not a B-ISDN. The basic look-ahead protocol allows provision of look-ahead between the incoming side of a network and the outgoing side of the same network. Decisions on whether to use basic look-ahead protocol ar
25、e made at each incoming gateway exchange. A mechanism exists between networks (e.g. at the T, reference point) to allow one network to indicate to another network that basic look-ahead is required. This Recommendation is applicable to equipments, supporting the look-ahead feature, to be attached at
26、either side of a T, reference point or coincident SB and TB reference point when used as an access to the public B-ISDN. 1.2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At
27、the 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 addition of the Recommendations and other references list
28、ed below. A list of the currently valid ITU-T Recommendations is regularly published. ITU-T Recommendation 1.41 3 (1 993), B-ISDN user-network interface. ITU-T Recommendation 4.2932.1 (1 996), Digital Subscriber Siganalling System No. 2 (DSS 2) - Generic functional protocol: Core functions. CCITT Re
29、commendation X.219 (1 988), Remote operations - Model, notation and service dejnition. CCITT Recommendation X.208 (1988), SpeciJication of Abstract Syntax Notation One (ASN. I). ITU-T Recommendation 4.293 1 (1 995), Digital Subscriber Signalling System No. 2 (DSS 2) - User-Network Interface (UNI) la
30、yer 3 speciJication for basic call/connection control. ITU-T Recommendation Z. 1 O0 (1 993), CCITT Speczjcation and description language (SDL). ITU-T Recommendation 4.2961.1 (1 999, Additional signalling capabilities to support trafic parameters for the tagging option and the sustainable cell rate p
31、arameter set. ITU-T Recommendation Q.2724.1 (1 996), B-ISDN User Part - Look-ahead without state change for the Network Node Interface. Recommendation 4.2964.1 (07/96) 1 STD-ITU-T RECMN Q*27b4*L-ENGL 175b 1111 qBb2571 Ob31345 94T 1.3 Definitions This Recommendation defines the following terms: 1.3.1
32、 invoke component: See Recommendation 4.2932.1 2, for the application of this component as defined in Recommendation X.219 3. Where reference is made to “xxxx“ invoke component, an invoke component is meant with its operation value set to the value of the operation “xxxx. 1.3.2 network: The DSS 2 pr
33、otocol entity at the network side of the user-network interface. 1.3.3 reject component: See Recommendation 4.2932.1 2, for the application of this component as defined in Recommendation X.219 3. 1.3.4 return error component: See Recommendation 4.2932.1 2, for the application of this component as de
34、fined in Recommendation X.219 3. Where reference is made to Ixxxx“ return error component, a return error component is meant which is related to an “xxxx“ invoke component. 1.3.5 return result component: See Recommendation 4.2932.1 2, for the application of this component as defined in Recommendatio
35、n X.219 3. Where reference is made to “xxxx“ return result component, a return result component is meant which is related to an kxxx“ invoke component. 1.3.6 1.3.7 that moment. 1.3.8 1.3.9 user: The DSS 2 protocol entity at the user side of the user-network interface. availability check Procedure to
36、 check whether the indicated capabilities are available at compatibility information: Information according to Recommendation 4.293 1 5. compatibility check: Procedure according to Recommendation 4.293 1 5. 1.4 Abbreviations This Recommendation uses the following abbreviations. ASN. 1 B-ISDN cs-2 DS
37、S 2 FIE ISDN “I OLEX PDU ROSE SAAL TLEX UNI 2 Abstract Syntax Notation One Broadband Integrated Services Digital Network Capability Set 2 Digital Subscriber Signalling System No. 2 Facility Information Element Integrated Services Digital Network Network-Network Interface Originating Local Exchange P
38、rotocol Data Unit Remote Operations Service Element Signalling ATM Adaptation Layer Terminating Local Exchange User-Network Interface Recommendation 4.2964.1 (07/96) 1.5 Description The look-ahead procedure allows a public or a private network to check whether compatible and incompatible terminal) a
39、re addressed and whether these terminal(s) are free or busy. This procedure can be used prior to the establishment of a calkonnection. Clauses 1.9 and 1.10 specify the generic portion of the procedure only. How a feature or an application makes use of the information obtained using these procedures
40、has to be specified in the relevant Recommendations referring to 1.9 and 1.1 O. 1.6 Operational requirements 1.6.1 Provision and withdrawal It is a user and a network option to provide the procedures described in this Recommendation. 1.6.2 Not applicable for the coincident SB and TB reference point.
41、 See 1.6.1 for the TB reference point. Requirements on the originating network side 1.6.3 See 1.6.1. Requirements on the destination network side 1.7 Primitive definitions and state definitions 1.7.1 Primitive definitions The following primitives are used: e LOOK-AHEAD.request e LOOK-AHEADindication
42、 e LOOK-AHEAD .response LOOK-AHEAD.confirm e ERROR.indication e AALESTABLISH.indication e AAL-RELEASEhdication 1.7.2 State definitions The state definition is for the purpose of the SDL diagrams, which are included in 1.13. 1.7.2.1 Look-ahead states at the coincident S, and T, reference point 1.7.2.
43、1.1 1.7.2.1.1.1 idle: Idle state. 1.7.2.1.1.2 look-ahead initiated: This state exists when the network has sent a look-ahead invoke component to the addressed user and has not yet received a response. Look-ahead states at the network side of the interface 1.7.2.1.2 Idle: Idle state. Look-ahead state
44、s at the user side of the interface Recommendation 4.2964.1 (07/96) 3 1.7.2.2 Look-ahead states at the T, reference point 1.7.2.2.1 1.7.2.2.1.1 idle: Idle state. 1.7.2.2.1.2 look-ahead invoked: This state exists when an entity has sent a look-ahead invoke component and has not yet received a respons
45、e. Look-ahead states at the outgoing side of the interface 1.7.2.2.2 1.7.2.2.2.1 idle: Idle state. 1.7.2.2.2.2 look-ahead invoked: This state exists when an entity has received a look-ahead invoke component and has not yet sent a response. Look-ahead states at the incoming side of the interface 1.8
46、Coding requirements 1.8.1 Operations and errors Table 1 contains the definition of the operations and types necessary for the look-ahead procedure using ASN.1 as defined in Recommendation X.208 4 and using the OPERATION macro as defined in Figure 4K.219 3. The formal definition of the component type
47、s to encode these operations and types is provided in Table A.UQ.2932.1 2. The inclusion of components in facility information elements is defined in Table 1 7.2.2. UQ.2932.1 2. Table UQ.2964.1- Look-ahead operations and errors Look-Ahead-Procedure ccitt recommendation q 2964 operations-and-errors (
48、1) DEFINITIONS EXPLICIT TAGS := BEGIN EXPORTS LookAhead, LookAheadTb; IMPORTS OPERATION, ERROR FROM Remote-Operation-Notation Cjoint-iso-ccitt remote-operations(4) notation(0) DSS2InformationElement FROM Embedded-DSS2-Types ccitt recommendation q 2932 embedded-dSS2types(7) Address FROM Addressing-Da
49、ta-Elements ccitt recommendation q 932 addressing-data-elements(7) CauseIndicators FROM LookAheadParameters ccitt recommendation q 2724 1 modules(0) parameters(2) versionl(0) 4 Recommendation Q.2964.1 (07/96) System Failure, TaskRefused FROM IN-CS-1-Errors (ccitt recommendation q 1218 moduies(0) cs-1-errors(0) versionl(0) ookAhead ,ookAhead ,ookResult ,ookAheadTb LookAheadTb := OPERATION ARGUMENT DSS2InformationEiement - The following information elements - shall be embedded in DSS2InformationElernent: - AAL parameters optional - A
