ITU-T Q 2959-1996 Digital Subscriber Signalling System No 2 - Call Priority《NO 2数字用户信令系统 呼叫优先》.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.2959 SERIES Q: SWITCHING AND SIGNALLING Broadband ISDN - B-ISDN application protocols for access si g na I I i n g (07196) Digital subscriber signalling system No. 2 - Call priority ITU-T Recommendation Q.2

2、959 (Previously CCITT Recommendation) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORK

3、ING Q. 1-Q.3 Q.4-Q . 59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SIGNALLING SYSTEM RI Q.60-(2.99 Q. 1 OO-Q. 1 1 9 Q.250-4.309 Q.310-Q.399 SPECIFICATION OF SIGNALLING SYSTEMS No. 4

4、 AND No. 5 Q.120-Q.249 SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIG I TAL EXCHANGES Q.400-Q.499 Q. 50O-Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600-Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700-Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850-Q.999 PUBLIC LAND MOBILE NETWORK Q. 1 OOO-Q

5、. 1 O99 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100-Q.1199 INTELLIGENT NETWORK Q.12004.1999 BROADBAND ISDN Q.2000-(2.2999 General aspects Q.2000-Q.2099 ATM adaptation layer Q.2100-Q.2199 Signalling network protocols Q .2200-Q.2599 Common aspects of B-ISDN application protocols for access signa

6、lling and Q.2600-Q.2699 network signalling and interworking B-ISDN application protocols of the network Q.2700-Q.2899 N application prot For further details, please refir to ITU-T List of Recommendations. COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information

7、Handling ServicesITU-T RECOMMENDATION 4.2959 DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 2 - CALL PRIORITY Summary This Recommendation defines the operation of the Digital Subscriber Signalling System No. 2 (DSS 2) for the handling of Call priority that may be provided, as a service provider option, fo

8、r Basic call and connection control at the TB or at the coincident SB and TB reference point of the User- Network Interface of the Broadband-Integrated Services Digital Network (B-ISDN). The call priority capability defined in this Recommendation allows for preferential treatment of high priority ca

9、lls during network congestions, based on the priority level allocated to the call. Source ITU-T Recommendation 4.2959 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 1996. COPYRIGHT International Telecommunications Union/

10、ITU TelecommunicationsLicensed by Information Handling ServicesFOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The IT Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ZTU. The ITLJ-T is resp

11、onsible 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 by th

12、e ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITLJ-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fali within ITU-Ts purview, the necessav stan

13、dards 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. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possib

14、ility 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 ITLJ members or others outside of t

15、he 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 lat

16、est information and are therefore strongly urged to consult the TSB patent database. O ITLJ 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 f

17、rom the IT. 11 Recommendation 4.2959 (07/96) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services STD-ITU-T RECMN Q.2959-ENGL B99b 48b259L Ob29707 Ol m 1 2 3 4 5 5.1 5.2 5.3 6 6.1 6.2 6.3 7 7.1 7.2 8 8.1 8.2 9 9.1 9.2 10 11 11.1 11.2 11.3 1

18、2 13 14 CONTENTS Scope References Definitions Abbreviations . Description . Application to interface structure . Capabilities supported by this Recommendation . General overview Operational requirements . Provision and withdrawal . Requirements on the originating network side . Requirements on the d

19、estination network side . Primitive definitions and state definitions Primitive definitions . State definitions Coding requirements Messages . 8.1.1 Modification of messages in Recommendation Q.293 1 . Information elements 8.2.1 Priority information element . Signalling procedures at the coincident

20、SB and TB reference points . Procedure at originating UNI . Procedure at destination UNI . Procedures at the TB reference point for intenvorking with private B-ISDNs . Intenvorking with other networks Intenvorking with CS-1 networks Interworking with DSS 1 Intenvorking with networks that do not supp

21、ort Call Priority Handling Interaction with supplementary services Parameter values . Dynamic description (SDLs) Page 1 1 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4 4 5 5 5 5 6 6 6 6 6 6 7 STD-ITU-T RECMN Q.2957-ENGL L99b 4Bb2591 Ob27708 T2b W COPYRIGHT International Telecommunications Union/ITU Telecommunic

22、ationsLicensed by Information Handling ServicesSTD-ITU-T RECMN Q=2959-ENGL L99b D 48bZ.591 Ob29708 T2b . . ?“a“ v COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesRecommendation Q.2959 DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 2 - CALL PR

23、IORITY (Geneva, 1996) 1 Scope This Recommendation specifies the messages, information elements and procedures needed to support priority treatment of calls on the User-Network Interface (UNI). Specifically, the following optional capabilities are provided: - The originating user may provide priority

24、 information for each call setup request. If not provided, the network shall include the priority information for the lowest priority. The originating side of the network shall provide for screening of the priority to ensure that the user does not exceed the highest assigned priority level. The netw

25、ork shall transport the priority information on the MI. The destination UNI shall deliver the priority information to the destination user. - - - The support of the Priority IE and associated procedures described in this Recommendation is optional for both the network and the user. 2 References The

26、following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of t

27、his Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. - CCITT Recommendation 1.255.3 (1 990), Community of in

28、terest supplementary services: Multi-level Precedence and Preemption service (MLPP) . CCITT Recommendation 1.255.4 (1 990), Community of interest supplementary services: Priority service. ITU-T Recommendation 1.4 13 (1 993), B-ISDN user-network interface. ITU-T Recommendation 4.735.3 (1993), Stage 3

29、 description for community of interest supplementary services using SS No. 7: Multi-level precedence and preemption. CCITT Recommendation 4.955.1 (1992), Stage 3 description for communiv of interest supplementary services using DSS 1: Closed user group. ITU-T Recommendation 4.955.3 (1 993), Stage 3

30、description for community of interest supplementary services using DSS 1: Multi-level Precedence and Preemption (MLPP). ITU-T Recommendation 4.21 30 (1 994), B-ISDN signalling ATM adaptation layer - Service SpeciJic Coordination Function for the Support of Signalling at the User-Network Interface (S

31、SCF at UNI). - - - - - - Recommendation 4.2959 (07/96) 1 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services- STD-ITU-T RECMN Q.2759-ENGL 377b 4862573 Ob27730 bB11 - ITU-T Recommendation 4.2610 (1995), Usage of cause and location in B-ISDN

32、 user part and DSS 2. ITU-T Recommendation 4.293 1 (1 995), Digital Subscriber Signalling System No. 2 - User- Network Interface (UNO layer 3 specification for basic callkonnection control. - 3 Definitions See Annex J/Q.293 1. 4 Abbreviations This Recommendation uses the following abbreviations: ATM

33、 Asynchronous Transfer Mode B-ISDN CUG Closed User Group DSS 2 ISDN Integrated Services Digital Network MLPP Multi-level Precedence and Preemption “I Network Node Interface Broadband Integrated Services Digital Network Digital Subscriber Signalling System No. 2 ROA Recognized Operating Agency SDL Sp

34、ecification and Description Language TCC Telephony Country Code UNI User-Network Interface 5 Description 5.1 Application to interface structure The layer 3 procedures apply to the interface structures defined in Recommendation 1.413. They use the functions and services provided by layer 2. The layer

35、 3 procedures request the services of layer 2 and receive information from layer 2 using the primitives defined in Recommendation 4.2130. These primitives are used to illustrate the communication between the protocol layers and are not intended to specifj or constrain implementations. 5.2 This Recom

36、mendation builds upon the capabilities in Recommendation 4.2931 for DSS 2 (see 1.5/Q.293 i). The additional capability supported by the signalling protocol specified in this Recommendation is the support of preferential treatment of high priority calls. Capabilities supported by this Recommendation

37、5.3 General overview This Recommendation specifies the information elements and procedures needed to support call priority handling on the User-Network Interface. 2 Recommendation Q.2959 (07/96) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling S

38、ervicesThe priority information is used to identi the priority of a call. It may be used by the network during call establishment. It may also be used by the called user to efficiently manage the incoming calls. The called user may also use this information for actions such as clearing an existing l

39、ower priority call and answering a higher priority call. Message 6 Operational requirements Reference 6.1 Provision and withdrawal The provision of this capability requires arrangements between the user and the network provider. 6.2 See 6.1 above. Requirements on the originating network side 6.3 See

40、 6.1 above. Requirements on the destination network side 7 Primitive definitions and state definitions 7.1 Primitive definitions Clause 8/Q.293 1 shall apply. 7.2 State definitions See clause 2lQ.293 1. 8 Coding requirements 8.1 Messages 8.1.1 Modification of messages in Recommendation 4.2931 Table

41、8-1 lists the existing 4.2931 message that has had its contents modifiec to support the Ca Priority. 8.1.1.1 SETUP This message is sent by the calling user to the network and by the network to the called user to initiate B-ISDN call establishment. See Table 8-2 for additions to the structure of this

42、 message shown in Table 344.293 1. Recommendation Q.2959 (0796) 3 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services - - STD-ITU-T RECMN Q=2757-ENGL 177b = Lidb2571 Ob27712 Li57 Information element Priority Table 8-2/Q.2959 - SETUP messag

43、e additional content Message type: SETUP Significance: Global Direction: Both Reference Direction Type Length 8.2.1 Both O 10 1 ext. 8.2 Information elements Coding IE instruction field standard Flag Res IE action indicator See clause 4/Q.293 1. The additional Priority IE is specified below. 1 ext.

44、8.2.1 Priority information element The Priority information element is used to identify the priority of a call. It is optionally present in the SETUP message on the originating UNI and on the destination UNI. The Priority information element is coded as shown in Figure 8-1. The length of this inform

45、ation Spare Priority element is 10 octets. 8 7 6 5 4 3 2 1 1st II digit 3rd II digit Priority information element identifier 2nd II digit 4th II digit - Priority (octet 5) Four binary coded bits indicating priority coded as follows: O000 level 1 (highest) O001 level 2 O010 level 3 001 1 level 4 0100

46、 level 5 (lowest) Octet 1 2 3 4 5 6 7 8 9 10 4 Recommendation Q.2959 (07196) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesOther values are reserved. - The domain consists of four international identification digits, called Network Id

47、entity (NI), followed by a pure binary coded national domain. - Each II digit is coded in a binary coded decimal representation from O to 9. The first digit is coded O. The Telephony Country Code (TCC) follows in the 2nd to the 4th II digits (the most significant TCC digit is in the 2nd II digit). I

48、f octet 7 is not required? it is coded all zeros. - National domain contains a code expressing in pure binary the number allocated to a national-specific domain to uniquely identi a customer domain across multiple ISDN networks. Bit 8 of octet 8 is the most significant bit and bit 1 of octet 10 is t

49、he least significant bit. NOTE - The code for national domain is to be assigned and administered by different national administrations. Domain (octets 6- 1 O) International Identification (II) (octets 6-7) National domain (octets 8-10) (See Note.) 9 Signalling procedures at the coincident S, and TB reference points 9.1 Procedure at originating UNI When subscribed to, the user will include the Priority IE in the SETUP message to convey the priority and domain of a call to the network. If not included, the network shall insert the Priority IE containing