ITU-T Q 50 1-2001 Signalling between International Switching Centres (ISC) and Digital Circuit Multiplication Equipment (DCME) including the control of compression decompression (S.pdf

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1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Q.50.1 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2001) SERIES Q: SWITCHING AND SIGNALLING International automatic and semi-automatic working Signalling for circuit multiplication equipment Signalling between International Switching Centres (ISC)

2、 and Digital Circuit Multiplication Equipment (DCME) including the control of compression/decompression ITU-T Recommendation Q.50.1 ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59

3、 Basic Recommendations Q.4Q.9 Numbering plan and dialling procedures in the international service Q.10Q.11 Routing plan for international service Q.12Q.19 General Recommendations relative to signalling and switching systems (national or international) Q.20Q.34 Tones for use in national signalling sy

4、stems Q.35Q.39 General characteristics for international telephone connections and circuits Q.40Q.47 Signalling for satellite systems Q.48Q.49 Signalling for circuit multiplication equipment Q.50Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDA

5、RD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEM No. 4 Q.120Q.139 SPECIFICATIONS OF SIGNALLING SYSTEM No. 5 Q.140Q.199 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309 SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399 SPECIFICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499 DIGITAL EXCHANGES Q

6、.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWO

7、RK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. Q.50.1 (07/2001)

8、i ITU-T Recommendation Q.50.1 Signalling between International Switching Centres (ISC) and Digital Circuit Multiplication Equipment (DCME) including the control of compression/decompression Summary This Recommendation describes a signalling interface between an International Switching Centre (ISC) a

9、nd a Digital Circuit Multiplication Equipment (DCME) that has the additional (compared to ITU-T Q.50) capability to control the compression/decompression function of the DCME. This signalling interface provides for the call by call control of a DCME in real time. Source ITU-T Recommendation Q.50.1 w

10、as prepared by ITU-T Study Group 11 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 July 2001. Keywords DCME. ii ITU-T Rec. Q.50.1 (07/2001) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The

11、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 telecommunications on a worldwide basis. The World Telecommunication Standard

12、ization 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 procedure laid down in WTSA Resolution 1. In some areas of information te

13、chnology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTEL

14、LECTUAL 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, validity or applicability of claimed Intellectual Property Rights, wh

15、ether 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 required to implement this Recommendation. However, implementors are

16、cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2002 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

17、microfilm, without permission in writing from ITU. ITU-T Rec. Q.50.1 (07/2001) iii CONTENTS Page 1 Scope. 1 2 References. 1 3 Definitions 1 4 Abbreviations 2 5 Requirements 2 6 Conceptual Model. 2 7 Network Architecture . 2 7.1 E1-Network 2 7.2 International Switching Centre. 3 7.3 Digital Circuit M

18、ultiplication Equipment. 3 8 Protocol. 4 8.1 Information elements 4 8.2 SDL. 4 Annex A Interface based on time slot 16 (frame 0-15) 8 Annex B Interface based on time slot 16 (frame 1-15). 8 B.1 Protocol. 8 B.1.1 Coding 8 B.1.2 Procedures 9 ITU-T Rec. Q.50.1 (07/2001) 1 ITU-T Recommendation Q.50.1 Si

19、gnalling between International Switching Centres (ISC) and Digital Circuit Multiplication Equipment (DCME) including the control of compression/decompression 1 Scope This Recommendation describes a signalling interface between an International Switching Centre (ISC) and a Digital Circuit Multiplicat

20、ion Equipment (DCME) with a built in device controller that allows a per call control of various functions in the DCME in real time. It is based on the interface described in ITU-T Q.50 1. In addition to the functions described in 1 that can be controlled by the switch, the compression/decompression

21、 function in the DCME can also be controlled. The DCME is of type 2 (see ITU-T Q.50 1). This interface is supported in E1-networks. The signalling interface defined in this Recommendation assumes a fixed relationship between the circuits of the ISC and the DCME. While this Recommendation is intended

22、 for use on international networks, the information defined here may be used within national networks. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publicat

23、ion, 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 below. A list of t

24、he currently valid ITU-T Recommendations is regularly published. 1 ITU-T Q.50 (2001), Signalling between Circuit Multiplication Equipment (CME) and International Switching Centers (ISC). 1 ITU-T Q.50 (1998), Implementors Guide. 2 ITU-T G.763 (1998), Digital circuit multiplication equipment using G.7

25、26 ADPCM and digital speech interpolation. 3 ITU-T G.767 (1998), Digital circuit multiplication equipment using 16 kbit/s LD-CELP, digital speech interpolation and facsimile demodulation/remodulation. 4 ITU-T G.768 (2001), Digital circuit multiplication equipment using 8 kbit/s CS-ACELP. 5 ITU-T G.7

26、04 (1998), Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44 736 kbit/s hierarchical levels. 3 Definitions This Recommendation uses the following terms: 3.1 Channel Associated Signalling (CAS): CAS refers to the channel associated signalling referred to in G.704 5. 3.2 E1 Facility:

27、A transmission link operating at 2048 kbit/s, supporting 30 or 31 64 kbit/s channels. 2 ITU-T Rec. Q.50.1 (07/2001) 3.3 external: A device is called external, when it is located outside of the switch. 4 Abbreviations This Recommendation uses the following abbreviations: CAS Channel Associated Signal

28、ling CCF Call Control Function DCME Digital Circuit Multiplication Equipment DCMECF DCME Control Function DCMESF DCME Switching Function ISC International Switching Centre 5 Requirements The protocol used between the ISC and the DCME must include the control signals/messages for the control of the c

29、ompression/decompression function in the DCME. 6 Conceptual Model T11113810-01DCMESF DCMECFCCFDCMEr1r2Functional PlanePhysical Planephysical connectionmappingrn relationship between communicating pairs of functional entitiesISCFigure 1/Q.50.1 Conceptual methodology model A master slave relation exis

30、ts between the DCME switching function (located in the switch) and the DCME control function (located in the DCME). 7 Network Architecture 7.1 E1-Network The DCME has a physical interface according to ITU-T G.704 5 which allows the DCME to be inserted in an E1 transmission facility. The control chan

31、nel is embedded in time slot 16 (CAS mode: a, b and d bit) of the E1 transmission facility. The use of time slot 16 in 2048 Kbit/s networks for channel associated signalling is defined in ITU-T G.704 5. ITU-T Rec. Q.50.1 (07/2001) 3 .T11113820-01DCMEabE1 ECDE1a DCMESFb DCMECFc-bit *)a,b,d-bit (time

32、slot 16; CAS)*) ITU-T Q.52ISCFigure 2/Q.50.1 ISC-DCME Interface in an E1-Network 7.2 International Switching Centre The ISC provides an E1 circuit interface and a control channel interface. The ISC also provides the logic to decide on a per call basis the control info to be sent to the DCME. The con

33、trol info is conveyed to the DCME via a control channel, see clause 10. T11113830-01DCMESF DCMESFQ.50.1Q.50.1Call ControlMaintenanceNOTE Communication between DCMESF and Call Control can either be direct or via the Signalling System ProcessSignallingSystem(RoutingBearerControletc)Signalling Systemin

34、ter exchange signallinginter exchangesignallingFigure 3/Q.50.1 Process Diagram 7.3 Digital Circuit Multiplication Equipment The DCME provides an E1 circuit interface and a control channel interface. The compression/decompression function can be enabled/disabled for each circuit individually. T111138

35、40-01E1 E1DCMECFcontrol channelDCMEfunctionsFigure 4/Q.50.1 Digital Circuit Multiplication Equipment 4 ITU-T Rec. Q.50.1 (07/2001) 8 Protocol 8.1 Information elements The information elements supported by this Recommendation are the same as in ITU-T Q.50 1 added by those contained in Table 1. Table

36、1/Q.50.1 Information elements for the control of compression/decompression Type of information element Notes Direction of the information element 1.1 compression/decompression not allowed Sent to inform the “outgoing“ DCME do not compress/decompress the bit stream, when a 3.1 kHz/speech select/seizu

37、re was sent to the DCME ISC DCME 1.2 decompression/compression not allowed Sent to inform the “incoming“ DCME do not decompress/compress the bit stream ISC DCME 8.2 SDL T11115840-02DCMEcomTo/From Call Control/Maintenance To/From DCME functionsystem DCMEcomsignalsame as in Q.50andComprdecompr, Comprd

38、ecomprnaenable cddisable cd/*Comprdecompr: compression and decompression allowedComprdecomprna: compression and decompression not allowedenable cd: enable compression and decompression functiondisable cd: disable compression and decompression function */Q.50(e.g. Voicerequest, Nonvoicerequest,Releas

39、e)ComprdecomprComprdecomprnaenable cddisable cdQ.50 (e.g. Failure)Q.50 (e.g. Availablevoice, AvailablenonvoiceOutofservice, Backinservice)Figure 5/Q.50.1 System “DCME communication“ ITU-T Rec. Q.50.1 (07/2001) 5 T11115850-02DCMESF DCMECFsee Figure 5Q.50block DCMEcomsignalsQ.50v.r./cdv.r./cd n.a.cd n

40、.a./* v.r./cd: voice request with compression and decompression allowed (ISC outgoing CME)v.r./cd n.a.: voice request withcompression and decompression not allowed (ISC outgoing CME)cd n.a.: compression and decompression not allowed (ISC incoming CME)NOTE The “v.r.“ signal is optional; see Q.50.Q.50

41、v.r./cdv.r./cd n.a.cd n.a.see Figure 5 see Figure 5 see Figure 5Call Control/MaintenanceDCME functionFigure 6/Q.50.1 Block “DCME communication“ 6 ITU-T Rec. Q.50.1 (07/2001) T11115860-02DCME req:= v.r.voice prdecomproutg DCME inc DCMEcomprdecomprnacomprdecomprcomprdecomprnav.r./cd v.r./cd n.a.cd n.a

42、.non voice r.Q.50INITIDLESEIZED OUTG.SEIZED INC.SEIZED OUTG. SEIZED OUTG.*) *)*)*)SEIZED INC.SEIZED INC.process DCMESFQ.50.1 protocol elementsvoice request/comprdecompr voice request/comprdecompr n.a. comprdecompr munication with*) no change compared with ITU-T Q.50Figure 7/Q.50.1 “Process DCMESF“ I

43、TU-T Rec. Q.50.1 (07/2001) 7 T11115870-02v.r./cdenable cdv.r./cd n.a. failureINITIDLESEIZED INC.*)SEIZED INC.disable cddisable cd*)SEIZED OUTG.*)/* v.r./cd: voice request (with compression and decompression)v.r./cd n.a.: voice request (with compression and decompression not allowed)remote v.r.: port

44、 related information from the remote DCMEenable cd: enable the compression and decompression functiondisable cd: disable the compression and decompression function */process DCMECFdcl port status := idle;cd n.a.SEIZED OUTG. SEIZED OUTG.communicate with remote DCMEcommunicate with remote DCMEcommunic

45、ate with remote DCMEremote v.r.port status:= local seizedport status:= local seizedport status:= remote seized*) no change compared with ITU-T Q.50Figure 8/Q.50.1 “Process DCMECF“ 8 ITU-T Rec. Q.50.1 (07/2001) Annex A Interface based on time lot 16 (frame 0-15) NOTE This annex is for further study.

46、Annex B Interface based on time slot 16 (frame 1-15) B.1 Protocol B.1.1 Coding Table B.1/Q.50.1 Signals Bits a, b and d of TS16 Signal No. Type of signal Direction ISC-DCME Forward af bf dfBackward ab bb dbGroup of information element 1 Circuit available for 64 kbit/s 1 0 1 1 0 1 2 Circuit available

47、 for 3.1 kHz data, speech 1 0 1 0 1 1 Load control 3 Circuit not available 1 0 1 0 0 1 4 64 kbit/s seizure 1 1 1 1 0 1 5 3.1 kHz/speech seizure 0 1 1 0 1 1 (0 1 1 1 0 1) (Note) 6 64 kbit/s positive acknowledgment 1 1 1 0 1 1 7 3.1 kHz/speech positive acknowledgement 0 1 1 1 0 1 Seizure Release (0 1

48、1 0 1 1) (Note) 8 Release 64 kbit/s 1 0 1 0 1 1 9 Release 3.1 kHz/speech 1 0 1 1 0 1 (1 0 1 0 1 1) (Note) 10 Maintenance release signal (after 3.1 kHz, speech seizure) 0 1 1 0 0 1 11 Maintenance release signal (after 64 kbit/s seizure) 1 1 1 0 0 1 12 Maintenance release acknowledgement 0 0 1 0 0 1 I

49、TU-T Rec. Q.50.1 (07/2001) 9 Table B.1/Q.50.1 Signals Bits a, b and d of TS16 Signal No. Type of signal Direction ISC-DCME Forward af bf dfBackward ab bb dbGroup of information element 13 CME clear of traffic 1 0 1 0 0 1 Maintenance 14 Out-of-service a 0 0 1 1 1 1 b 0 1 1 1 1 1 c 1 0 1 1 1 1 d 1 1 1 1 1 1 15 Out-of-service acknowledgement 0