ITU-T X 96-2000 Call Progress Signals in Public Data Networks Series X Data Networks and Open System Communications Public Data Networks - Network Aspects (Study Group 7 15 pp)《公用数.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU X.96 (03100) SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUN I CATI ON S Public data networks - Network aspects Call progress signals in public data networks ITU-T Recommendation X.96 (Previously CCITT Recomme

2、ndation) STD-ITU-T RECMN X=Sb-ENGL 2000 48b2591 Ob74590 02T m ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS PUBLIC DATA NETWORKS Services and facilities Interfaces Transmission, signalling and switching Network aspects Maintenance Administrative arrangements Model and n

3、otation Service definitions Connection-mode protocol specifications Connectionless-mode protocol specifications PICS proformas Protocol Identification Security Protocols Layer Managed Objects Conformance testing General Satellite data transmission systems MESSAGE HANDLING SYSTEMS DIRECTORY OS1 NETWO

4、RKING AND SYSTEM ASPECTS OPEN SYSTEMS INTERCONNECTION INTERWORKING BETWEEN NETWORKS Networking Efficiency Quality of service Naming, Addressing and Registration Abstract Syntax Notation One (ASN. 1) OS1 MANAGEMENT Systems Management framework and architecture Management Communication Service and Pro

5、tocol Structure of Management Information Management functions and ODMA functions SECURITY OS1 APPLICATIONS Commitment, Concurrency and Recovery Transaction processing Remote operations OPEN DISTRIBUTED PROCESSING X. 1-X. 19 X.20-X.49 X.50-X. 89 X90-X.149 X. 150-X. 179 X. 180-X. 199 X.200-X.209 X.21

6、-X.219 X.220-X.229 X.230-X.239 X.240-X.259 X.260-X.269 X.270-X.279 X.280-X.289 X. 290-X . 299 X.300-X.349 x.350-x.399 X.400-X.499 X.500-X.599 X.600-X.629 X.630-X.639 X.640-X.649 X.650-X.679 X.680-X.699 X. 700-X . 709 X.710-X.719 X.720-X.729 x.730-x.799 X.800-X. 849 X.850-X.859 X.860-X.879 X.880-X.89

7、9 X.900-X.999 For further details, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN X.7b-ENGL 2000 48b2595 Ob74575 Tbb D ITU-T RECOMMENDATION X.96 CALL PROGRESS SIGNALS IN PUBLIC DATA NETWORKS Summary This Recommendation identifies and categorizes call progress signals used in public d

8、ata networks. This revision slightly restructures the text and adds call progress signals for frame relay data networks. Call progress signals for circuit switching are not changed and call progress signals for packet switching are slightly corrected. Source ITU-T Recommendation X.96 was revised by

9、ITU-T Study Group 7 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 3 1 March 2000. Recommendation X.96 (03/00) i FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The ITU Telecommunication st

10、andardization 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 basis. The World Telecommunication Standardization Conferen

11、ce (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 procedure laid down in WTSC Resolution No. 1. In some areas

12、 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 telecommunication administration and a recognized opera

13、ting 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 ITU takes no position concerning the evidence, validity or applicability of claimed Intell

14、ectual 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 patents, which may be required to implement this Recommendati

15、on. 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 2000 All rights reserved. No pari of this publication may be reproduced or utilized in any form or by any means, electronic or mechani

16、cal, including photocopying and microfilm, without permission in writing from the ITU. It Recommendation X.96 (03/00) STDmITU-T RECMN XOSb-ENGL 2000 48b259L Ob74593 839 CONTENTS Page 1 Introduction 1 2 Scope 1 3 References 1 4 Abbreviations 2 5 General description . 2 . Recommendation X.96 (03100) 1

17、11 STD-ITU-T RECMN XmSb-ENGL 2000 = 48b259L Ob74594 775 Recommendation X.96 CALL PROGRESS SIGNALS IN PUBLIC DATA NETWORKS (Geneva, 1976; amended at Geneva, I980 and Malaga-Totremolinos, 1984, Melbourne, I988 and Helsinki, I993 and Geneva, 2000) 1 Introduction The establishment in various countries o

18、f public data networks for data transmission creates a need to inform the caller about the progress of the call. This Recommendation lays down the call progress signals in public data networks indicating the circumstances which have prevented the connection being established to a called user. 2 Scop

19、e This Recommendation describes the call progress signals in circuit switched, packet switched and frame-relay data networks. Besides of informing of the caller about the reasons that have prevented the establishing of the call and also about the progress made toward establishing the call, call prog

20、ress signals in some cases inform the users about network congestion which may impact on data integrity. Call progress signals may be transmitted to calling and called DTE when call is reset or cleared as a cause of the reset or the clearing. 3 References The following ITU-T Recommendations and othe

21、r 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 this Recommendation are therefore encoura

22、ged 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. ITU-T Recommendation X.2 (2000), International data transmission services and optional user fac

23、ilities in public data networks and ISDNs. ITU-T Recommendation X.7 (2000), Technical characteristics of data transmission services. ITU-T Recommendation X.20 (1988), Interface between Data Terminal Equipment (DTE) and Data Circuit- terminating Equipment CE) for start-stop transmission services on p

24、ublic data networks. ITU-T Recommendation X.20 bis (1988), Use on public data networks of Data Terminal Equipment TE) which is designed for interfacing to asynchronous duplex V-series modems. CCITT Recommendation X.21 (1992), Interface between Data Terminal Equipment and Data Circuit- terminating eq

25、uipment for synchronous operation on public networks. ITU-T Recommendation X.21 bis (1988), Use on public data networks of Data Terminal Equipment (DTE) which is designed for interfacing to synchronous duplex V-series modems. ITU-T Recommendation X.25 (1996), Interface between Data Terminal Equipmen

26、t (DTE) and Data Circuit- terminating Equipment CE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit. ITU-T Recommendation X.28 (1 997), DTE/DCE interface for start-stop mode Data Terminal Equipment accessing the packet assembly/disassembly facili

27、ty (PAD) in a public data network situated in the same counLy. Recommendation X.96 (03/00) 1 STDmITU-T RECMN X-Sb-ENGL 2000 9 rieb2591 Ob7ri595 601 ITU-T Recommendation X.32 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit- terminating Equipment CE) for terminals operating in

28、 the packet mode and accessing a packet switching public data network through a public switched telephone network or an integrated services digital network or a circuit switched public data network. ITU-T Recommendation X.36 (2000), Interface between Data Terminal Equipment (DTE) and Data Circuit- t

29、erminating Equipment (DCE) for public data networks providing frame relay data transmission service by dedicated circuit. Abbreviations This Recommendation uses the following abbreviations: DCE Data Circuit-terminating Equipment DSE Data Switching Exchange DTE Data Terminal Equipment PVC Permanent V

30、irtual Circuit ROA Recognized Operating Agency SVC Switched Virtual Circuit vc Virtual Circuit 5 General description The call progress signals and their related circumstances giving rise to them are defined in Table 1. Call progress signal format and coding shall be in accordance with relevant inter

31、face specifications in the X-series Recommendations. In a circuit-switched service, call progress signals may only be transmitted during the call Set-up phase. In a packet- switched service and frame-relay service they may also be transmitted during the data transfer phase and the call clearing phas

32、e of a virtual call. The call progress signals are categorized according to their significance to the network or DTE and the type of action expected of the DTE receiving the signal, refer to Table 2. The sequence of call progress signals in Table 1 implies, for categories C and D, the order of call

33、Set-up processing by the network. In general the DTE can assume, on receiving a call progress signal, that no condition higher up the table is present. Network congestion, network out-of-order, long-term network congestion and no connection are exceptions to this general rule. The actual coding of c

34、all progress signals does not necessarily reflect this sequence. Except as noted in Note 4 to Table 1, all call progress signals will be extended to the DTE unmodified. Users and DTE manufacturers are warned to make due allowance for possible later extensions to this table by providing appropriate f

35、all- back routines for unexpected signals. 2 Recommendation X.96 (03/00) STDmITU-T RECMN XmSb-ENGL ZOO0 E 48b259L Ob7459b 548 E Table 1m.96 Call progress signai Definition Category A Circuit switching Terminal called The incoming call was signalled to the DTE and call acceptance is awaited. The call

36、 has been redirected to another number assigned by the originally called subscriber, because, for example, it was busy. A Redirected call Connect when free The called number is busy and the call has been placed in a queue. The call will be connected when the called number becomes free if the caller

37、waits. A The facility registration or cancellation requested by the calling DTE has been confirmed by the network. B Regisratiodcan- cellation confrmed The redirection facility is active. B Redirection facility active Redirection facility not active The redirection facility is not active. B No conne

38、ction Cause unspecified. CI M A transmission error has been detected in the selection signals by the first Data Switching Exchange (DSE). c2 M Selection signai transmission error Recommendation X.96 (03100) 3 STD-ITU-T RECMN X-Sb-ENGL 2000 m 48b259L Ob74577 484 = Table 1K.96 (cont.) Applicable to Fr

39、ame relay Packet switching Call progress signal Definition Local procedure emr Category See Note Circuit switching vc PVC svc PVC DI M M - M M 3 i procedure error caused )y the DTE is detected )y the DCE at the local ITE/DCE interface. ossible reasons are ndicated in relevant X- leries Recommendatio

40、ns m interfaces (e.g. ncorrect format, :xpiration of a time-out). 4 condition exists in the ietwork such as: i) temporary network congestion, 2) temporary fault condition within the network, including procedure error within a network or an international link. M M M M c2 M Network congestion Network

41、out of order emporary inability in the network to handle data traffic. c2 M Network has no appropriate circuit I channel presently available to handle the call. c2 17 No circuit/ channel available I A facility requested by the calling DTE (circuit switching, packet switching or frame-relay services)

42、 or the called DTE (packet switching service only) is detected as invalid by the DCE at the local DTE/DCE interface. Possible reasons include: request for a facility which has not been subscribed to by the DTE; request for a facility which is not available in the local network; request for a facilit

43、y which has not been recognized as valid by the local DCE. D1 M 18 invalid facility request 4 Recommendation X.96 (03/00) Definition I D1 - D1 - STDOITU-T RECMN X-Yb-ENGL 2000 48b2592 Ob74598 310 Table 1K.96 (cont.) I Applicable to c Cali progress signai Packet switching See Note Frame relay Categor

44、y Circuit switching vc PVC svc PVC Tacility rejected 19 Facility requested by the Ealling DTE cannot be provided by the network. he ROA nominated by the calling DTE is unable to forward the call. 4 tOA out of xder The called DTE has been assigned a new number. :hanged iumber Not obtainable The calle

45、d DTE address is out of the numbering plan or not assigned to any DTE. D1 I M M M Access barred The calling DTE is not permitted for the connection to the called DTE. Possible reasons include: unauthorised access between the calling DTE and the called DTE; incompatible closed user group. I No respon

46、se Called DTE does not respond within the prescribed period of time. The called DTE has not subscribed to the reverse charging acceptance facility. M (Ml 16 Reverse charging acceptance not subscribed Incompatible user class of service The called DTE belongs to a user class of service which is incomp

47、atible with that of the calling DTE. 5 Fast select acceptance not subscribed The called DTE has not subscribed to the fast select acceptance facility. The remote DTEDCE interface or a transit network does not support a function or facility requested. Incompatible destination Ship absent The called s

48、hip is absent. 12 M Recommendation X.96 (03/00) 5 FS FS FS M - FS FS FS - - FS M - FS - - Table 1X.96 (cont.) Applicable to Packet switching 7 (See Note 7) Circuit switching Call progress signal Category See Note Frame relay Definition svc PVC - rransit network inaccessible 15 Frame-relay network ca

49、nnot route the call through the transit network specified by the calling DE. The remote number is out of order. Possible reasons include: i) DTE is uncontrolled not ready; 2) DCEpoweroff; 3) network fault in the local loop; 4) in packet switched services only: X.25 layer 1 not functioning; X.25 layer 2 not in operation. The local loop associated with the called DCE is faulty. D2 DI or D2 Out of order (See Note 6) M M 8 Network fault in the local loop D2 M (See Note 20) 9 (See No