ITU-T G 960-1993 Access Digital Section for ISDN Basic Rate Access (Study Group XVIII) 35 pp《ISDN 基础率取数用存取数字单元》.pdf

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1、CCITT RECPlN*G*SbO (REV*L) 93 4862591 0580349 24T W INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.960 (03/93) DIGITAL SECTIONS AND DIGITAL LINE SYSTEMS ACCESS DIGITAL SECTION FOR ISDN BASIC RATE ACCESS ITU-T Recommendation G.960 (Previously “CCIlT Reco

2、mmendation”) CCITT RECNN*G.960 (REVxL) 93 W 4862593 0580350 TbL FOREWORD The ITU Telecommunication Standardization Sector (-T) is a permanent organ of the International Telecom- munication Union. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendati

3、ons on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the ITU-T Study Groups which, in their tum, produce Recommendations on these topics. ITU-

4、T Recommendation G.960 was revised by the IT-T Study Group XVIII (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT ceased to exist as of 28 February 1993. In its place,

5、 the ITU Telecommunication Standardization Sector (IT-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to refe

6、rences containing the acronyms “CCITT, CCIR or IFFU3” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the new ITU structure. 2 telecommunication administration and a recognized operating ag

7、ency. In this Recommendation, the expression “Adminisiration” is used for conciseness to indicate both a O IT 1993 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 permi

8、ssion in writing from the ITU. CCITT RECNN*G.SbO (REV*L) 93 48b259L 858035L 9T8 9 1 2 3 4 5 CONTENTS Page General 1 I .I scope 1 1.2 Configuration 1 1.3 Application . 1 i .4 Abbreviations 1 Modelling and relationship between the access digitai section and the ET 2 Functions . 3.1 B-channel . 3.2 D-c

9、hannel . 3.4 Octet timing 3.5 Activation . 3.6 Deactivation 3.3 Bit timing . 3.7 Power feeding . 3.8 Operation and maintenance . Network performance . 7 4.1 Availability . 7 4.2 Signal transfer delay . 7 4.3 Error performance . 7 4.4 Jitter . 7 Activatioddeactivation 7 5.1 Functional capabilities 7

10、5.2 Modelling . 8 5.3 Activatioddeactivation procedures 10 5.4 Description of the state transition tables II 5.5 Activation time . 13 6 Operation and maintenance . 15 6.1 General . 15 6.2 Control facilities . 16 6.3 Monitoring 17 7 Control channel CV, 19 Annex A - System management requiremen 20 A.1

11、 Introduction 20 A.2 System management requirements 20 A.3 Description of the ET layer 1 state transition table 21 Annex B - Partial activation of the access digitai section 25 B.l Introduction 25 B.3 Description of the ET state transition table 26 B.2 Description of the state transition tables 25 R

12、ecommendation G.960 (03/93) 1 CCITT RECMNxG.760 (REVxI,) 93 W 4862571 0580352 834 M Recommendation 6.960 ACCESS DIGITAL SECTION FOR ISDN BASIC RATE ACCESS (Melbourne, 1988; revised Helsinki, 1993) 1 General 1.1 Scope This Recommendation describes the characteristics of an access digital section for

13、the ISDN basic rate access between the user-network interface (at T reference point, defined in Recommendation 1.411) and the local exchange (at Vi reference point defined in Recommendation Q.512) supporting the recommended channel structure 2B + D and the required additional functions. In this Reco

14、mmendation and unless otherwise indicated, the term TE is used to indicate terminating layer 1 aspects of TEl, TA and NT2 functional groups. When the term TE indicates terminating layer 1 aspects of TEl, then according to Figure 2A.411, the S and T reference points coincide. The terminology used in

15、this Recommendation is contained in Recommendations I. 112 and G.70 1. 1.2 Configuration Figure 1 shows the boundaries of the access digital section in relation to the digital system definition. The concept of the access digital section is used in order to allow a functional and procedural descripti

16、on and a definition of the network requirements. Note that reference point T and Vi are not identical and therefore the access digital section is not symmetric. The concept of a digital transmission system is used in order to describe the characteristics of an implementation, using a specific medium

17、, in support of the access digital section. NOTE - The T and V reference points are defied in Recommendations 1.41 1 and 4.512. 1.3 Application The basic access digital section may be appiied as given in Figure 2 for: - - - direct access to the local exchange (Vi-reference point); access via a basic

18、 access multiplex equipment (V4-interface) to the local exchange; access via a basic access concentrator (V2-interface) to the local exchange. 1.4 Abbreviations A number of abbreviations are used in this Recommendation. Some of them are commonly used in the ISDN reference configuration wbiie others

19、are created only for this Recommendation. The latter are given below: Cvl DS Access digital section FE INFO SIG DTS Digitai Transmission System Control Channel at Vi reference point Function Element used between ET and LT Information element defined at the user network interface Signal between LT an

20、 NT1 Recommendation 6.960 (03/93) 1 k Digitd transmission system d Access digital sech T1814240g2/d01 NOTES 1 2 Digitai transmission system refers to a line system using metallic pairs, optical fibres or radio systems. The line transceivers in the NTl and LT are part of the digital transmission syst

21、em. FIGURE 1/G.960 Access digital section and transmissioo system boundaries 2 Modelling and relationship between the access digital section and the ET The general model shown in Figure 3 depicts the whole ISDN customer access layer 1 and adjacent entities and provides the basis to describe the func

22、tions performed by the access digital section and those performed by TE, ET and system management and how various functions are grouped. In particular, according to this model the activatioddeactivation procedures and maintenance functions specified in this Recommendation are not confined to functio

23、ns performed by the access digitai section but include functions associated with ET layer 1. This model includes primitive procedures between ET layer 1, ET layer 2 and system management as follows: Recommendations 1.430 and Q.920/Q.921 interactions between ET layer 1 and ET layer 2, and ET layer 1

24、and system management based on PH and MPH primitives, respectively, as defined in Recom- mendation 1.430. Tbese interactions are for the support of functions specified in Recommenda- tions Q.920 and Q.921; interactions between ET layer 1 and system management for the support of functions associated

25、with the access digitai section, based on MPH primitives. The primitive procedures defined in this model do not conflict with those specified for the TE in Recommenda- tion 1.430. This model does not constrain layer 1 arrangements between LT and NT1, (it is also applicable to remote access applicati

26、on as shown in Figure 2), or the digitai transmission system technology. 2 Recommendation G.960 (03/93) CCITT RECMN*G.960 (AEVrL) 93 = 4862593 O580354 607 M I Access digital section 4 b r- 1 Localexchange 4 Access digital section h Concentrator I Access digitai section b I_ I 1 I Multiplexer I I NOT

27、ES 1 2 may be foreseen. 3 or concentrator and the local exchange will be used. The LT may be integrated together with the ET or separate (as integral part or outside of the local exchange). The application of one regenerator in an access digital section using a digital transmissions system for metal

28、lic pairs Local and remote application are envisaged. For the remote case a transparent link between the remote multiplexer FIGURE 2/G.960 Application of the access digitai section Recommendation G.960 (03/93) 3 CCITT RECMNaG.9bO (REVxL) 93 = Y862591 0580355 543 = I o i. m + I W 9 3 4-i O 4 Recommen

29、dation G.960 (03/93) CCITT RECNNxG.9bO (REV*I,) 93 D 4862593 D5B035b 48T b 4 b 4 b 4 3 Functions Figure 4 shows the functions which bave to be supported by the basic access digital section. 2 B Channels D Channel Bit timiw T reference point Access digital section V1 referencepoint b 4 b 4 4 4 Octet

30、timing b Activation (Note 3) 4 (Note 1) 4 (Note 1) Deactivation (Note 3) E 7- Paver feeding (Note 2) b (Note 1) Operation and maintenance T181427092ld04 NOTES 1 2 This function is optional. 3 access digital section and the user-network interface. However, for consistency with Recommendation 1.430, t

31、hey are described as separate functions. These functions are conveyed by the Cv, channel across tbe V, reference point. The activation and deactivation functions are concerned with the operation of the FIGURE 4/G.960 Functions of the access digital section 3.1 B-chan ne1 This function provides, for

32、each direction of transmission, two independent 64 kbit/s channels for use as B-channels (as defined in Recommendation 1.412). 3.2 Dchannel This function provides, for each direction of transmission, one D-channel at a bit rate of 16 kbit/s (as defined in Recommendation 1.412). 3.3 Bit timing This f

33、unction provides bit (signai element) timing to enable the receiving equipment to recover information from the aggregate bit stream. At the V 1 reference point, the bit timing function is used for both transmit and receive data. Recommendation 6.960 (03/93) 5 CCITT RECNN*G-qbO (REV*L) 93 48b259L 058

34、0357 316 3.4 Octettiming This function provides 8 kHz octet timing for the B-channels. 35 Activation 3.5.1 Activation from ET This function places ail the functions of the access digital section into a normal operating mode and supports the activation of the interface at the T reference point accord

35、ing to Recommendation 1.430. This takes into account: - power down mode; - initial power up; - a failure condition. The procedures and exchange of information are described in 5. An activation should be possible to a state which allows maintenance actions to be performed in the access digital sectio

36、n even when there is no customer equipment connected to the T reference point. In case a basic access digital section uses a digital transmission system for a metallic line, an additional mode of operation may be applied for activatioddeactivation, which is to activatddeactivate the access digital s

37、ection only (partial activation of the DS, Le. no signal shall be sent from the NT1 to the interface at the T reference point, but signals can be received for activation from the user side). This is optional. 3.5.2 This function supports activation of the access digital section and of the interface

38、at the T reference point according to Recommendation 1.430. Request for activation from TE These functions are conveyed by the Cvl-channel (see 7). 3.6 Deactivation This function permits the interface at the T reference point and the access digital section to be placed in a low power consumption mod

39、e. The procedures and exchange of information are described in 5. Deactivation should be initiated only by the exchange (ET). This function is conveyed by the Cvl-channel (see 7). 3.7 Power feeding This function provides for remote power feeding of NTl and optionally the TE via the user-network inte

40、rface in accordance with 9A.430. 3.8 Operation and maintenance This function supports required actions and information for operating and maintaining the access digital section controlled by the ET as defined in Recommendation 1.603. Four categories of functions have been identified: - - - indication

41、s of fault conditions; - commands regarding LT, regenerator, or NTl; information from LT, regenerator, or NT1; control of access digital section power feeding. These functions are conveyed by the Cvi-channel (see 7). 6 Recommendation 6.960 (03193) CCITT RECMN*G-SbO (REV*1) 93 m 4862591 0580358 252 m

42、 4 Network performance 4.1 Availability The definition of availability is given in Annex AIG.821. The availability objective of the access digital section should be consistent with the availability requirement for the hypothetical reference access digital section as given in Recommendations G.801 an

43、d 1.350. 4.2 Signai transfer delay Signal transfer delay is specified for B- and D-channels and is defined as absolute signal or the access digital section partially (this activation is related to controlling the configuration of the access; it is a network option); 2) Recommendation 6.960 (03/93) 7

44、 CCITT RECMN*G.bO (REVEL) 93 m 48b259L O580359 199 m b) deactivate: 1) 2) the layer 1 of the user-network interface at reference point T and the access digitai section; or the iayer 1 of the user-network interface at reference point T only. The functional capabilities defined in 5.1.2 a) 2) allow ma

45、intenance actions in the access digital section which do not affect the deactivated user-network interface at reference point T to be performed if required. In some applications they also permit the access digital section to be placed in a mode where the full information transfer capability is avail

46、able while the user-network interface at reference point T remains deactivated. The procedures for the activation or deactivation of the layer 1 of the user-network interface at reference point T comply with 6.2n.430. These procedures are based on a repertoire of INFO signals as defined in Recommend

47、ation 1.430 (see Table 4n.430). The procedures at VI reference point are based on a repertoire of function elements (FES). These FES have specific relationships to primitives between the ET layer 1 and ET iayer 2, and ET layer 1 and system management for the activation or deactivation of the iayer 1

48、 of the user-network interface in accordance with 6.2n.430 and Recommenda- tions Q.920 and 4.921. The means for defining these interactions are the primitive procedures (see Figure 5D.430) based on a repertoire of PH- and MPH-primitives. 5.2 Modelling 5.2.1 General The model for activatioddeactivati

49、on procedures is given in 2. It is recognized that activatioddeactivation is a process between the subscriber installation and local exchange requiring appropriate functionality at both ends. The model contained in 2 includes the functional blocks relevant to activatioddeactivation and depicts the primitives related to the activatioddeactivation procedures. 5.2.2 Partitioning of functions Recommendation 1.430 defines the network side of the user-network interface at reference point T as one functional block which supports the iayer 1 activatioddeactivation procedures across t