1、STD-ITU-T RECMN G.9b2 ADD 1-ENGL 1997 48b2591 Ub39383 11T E INTERNATIONAL TELECOMMUNICATION UNION lTU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.962 Amendment I (06197) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital transmission systems - Digital sections and
2、 digital line system - Digital section and digital transmission systems for customer access to ISDN Access digital section for ISDN primary rate at 2 048 kbi t/s Amendment I : Maintenance channel ITU-T Recommendation G.962 - Amendment 1 (Previously CCITT Recommendation) - STD.ITU-T RECMN G-9b2 AND 1
3、-ENGL 1777 - 48b257l1 Ob39184 05b m ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS NTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS NTERNATIONAL ANALOGUE CARRIER SYSTEM -RANSMISSION SYSTEMS NDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTE
4、MS ON METALLIC LINES ;ENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER- ;ENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE VITH METALLIC LINES jYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION OORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY rRA NSMISSIO N MEDIA CHARACTERIST
5、ICS IIGITAL TRANSMISSION SYSTEMS TERMINAL EQUIPMENTS General Coding of analogue signals by pulse code modulation Coding of analogue signals by methods other than PCM Principal characteristics of primary multiplex equipment Principal characteristics of second order multiplex equipment Principal chara
6、cteristics of higher order multiplex equipment Principal characteristics of transcoder and digital multiplication equipment Operations, administration and maintenance features of transmission equipment Principal characteristics of multiplexing equipment for the synchronous digital hierarchy Other te
7、rminal equipment General aspects Design objectives for digital networks Quality and availability targets Network capabilities and functions SDH network characteristics Telecommunications management network General Parameters for optical fibre cable systems Digital sections at hierarchical bit rates
8、based on a bit rate of 2048 kbiffs Digital line transmission systems on cable at non-hierarchical bit rates Digital line systems provided by FDM transmission bearers Digital line systems Di ita1 section and digital transmission systems for customer access to Optical fibre submarine cable systems Opt
9、ical line systems for local and access networks DIGITAL NETWORKS DIGITAL SECTIONS AND DIGITAL LINE SYSTEM ISBN G. 1 OO-G. 199 G.200-G.299 G.300-G.399 G.400-G.449 G.450-G.499 G.600-G.699 G ,700-G . 799 G.700-G.709 G.710-G.719 G.720-G.729 G .730-G. 739 G. 740-G. 749 G.750-G.759 G.760-G.769 G.770-G.779
10、 G.780-G.789 G.790-G.799 G.800-G.899 G. 800-G. 809 G.810-G.819 G.820-G.829 G ,830-G, 839 G. 840-G. 849 G. 850-G. 8 59 G.900-G.999 G. 900-G. 909 G.910-G.919 G. 920-G. 929 G.930-G.939 G.940-G.949 G. 950-G . 959 G.960-G.969 G. 970-G. 979 G .980-G. 999 For further details, please refer to ITU-T List of
11、Recommendations STD-ITU-T RECNN G-9b2 AND 1-ENGL 1797 9 48b2571 Ob39185 T92 = ITU-T RECOMMENDATION G.962 ACCESS DIGITAL SECTION FOR ISDN PRIMARY RATE AT 2048 kbit/s AMENDMENT 1 Maintenance channel Source Amendment 1 to ITU-T Recommendation G.962, was prepared by ITU-T Study Group 13 (1997-2000) and
12、was approved under the WTSC Resolution No. 1 procedure on the 20th of June 1997. 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.
13、 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 Conference (WTSC), which meets every four years, establishes the topi
14、cs for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recornmendations 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,
15、 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 operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws atte
16、ntion 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 Intellectual Properiy Rights, whether asserted by ITU members or o
17、thers outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had/had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may no
18、t represent the 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 permi
19、ssion in writing from the ITU. II Recommendation G.96YAmd.l (06/97) . STD-ITU-T RECMN G-9b2 AND 1-ENGL 1997 48b2591 Ob39187 Ab5 CONTENTS C.7 Maintenance channel C.7.1 Introduction . C.7.2 Maintenance channel layered structure . Appendix I . Recommendation G.962Amd.l (06/97) Page 1 1 1 6 . 111 Recomm
20、endation G.962 ACCESS DIGITAL SECTION FOR ISDN PRIMARY RATE AT 2048 kbit/s AMENDMENT 1 Maintenance channel (Geneva, I99 7) Introduce a new subclause C.7 into Recommendation G.962, Annex C. C.7 Maintenance channel C.7.1 Introduction The Maintenance Channel (MC) consists of a 4 kbit/s data channel usi
21、ng the international S, bit in the non-frame alignment TS O word. The MC shall be used for transporting reports and sending commands between the ET and the other FUS. See Figure C. 1. NT 1 LT ET MC Control centre T1308180-96 + MC 4 2 Mbits Figure C.UG.962 - Maintenance channel outline for PRA The ma
22、intenance channel includes a data protocol which is capable of a maximum of 70messagessecond and should function as specified and be secure with a maximum BER of 1 x Each PRA digital section shall use its own MC for message signals pertaining to its own operation and maint enance faci 1 it ie s. for
23、 the PRA digital section. C.7.2 Maintenance channel layered structure The structure of the MC is based on a three-layer model. These are: 1) physical layer; 2) digital section control layer; Recommendation G.962IAmd.l (06/97) 1 - STD-ITU-T RECMN G-9b2 AMD 1-ENGL 1997 48b2591 Ob37189 b38 876543 2 1 F
24、LAG O 1 1 1 1 1 1 O 3) message layer. 1 C.7.2.1 Physical layer The data for the MC are inserted and removed in the TS O non-frame alignment word bit 4. This bit is specified in Recommendation G.704 as Sa4. Each FU shall generate a data stream toward its counterpart as well as monitoring it. The Sa,
25、bit occurs every 250 microseconds giving an effective data rate of 4 kbits. ADDRESS low-order octet CONTROL MESSAGE LAYER FCS C.7.2.2 The protocol used to convey the messages between the FU shall be LAPD which is a protocol that operates at the data link layer of the OS1 architecture. This protocol
26、is specified in Recommendations 4.920 and 4.921. Because the uncompiex function that the protocol is put to, only the unacknowledged operation is required in this case. With this type of operation, the layer 3 messages are transmitted in Unnumbered Information (UI) frames. At the control layer, the
27、U1 frames are not acknowledged as this is covered in acknowledgment messages at the layer 3 level. Even if transmission and format errors are detected, no error recovery mechanism is defined at this layer. When the MC is in an idle state, each control layer generator shall continuously send the idle
28、 code which is O1 11 11 10. The ET shall act as the network provider and the NTl, LT as the user. The format of the LAPD frame is shown in Figure C.2 below. Data link layer peer-to-peer exchanges are in frames conforming to Figure C.2. Digital section data link control layer 3 4 5 to n-3 n-2 I ADDRE
29、SS high-order octet I 2 I FCS FLAG O 1 1 1 1 1 1 O Figure C.2lG.962 - Data link frame structure C.7.2.2.1 Flag sequence All frames shall start and end with the flag O1 11 1 1 10 sequence. The closing flag sequence of a frame cannot be used as the opening flag for the following frame. 2 Recommendatio
30、n G.962lAmd.l (06/97) STD-ITU-T RECMN G-9b2 AMD 1-ENGL 1777 48b259L Ob39190 35T 8 C.7.2.2.2 Address field This field shall consist of two octets as shown in Figure C.3. 7 6 5 4 3 2 1 SAPI O I O 1 O O TE1 = O000000 for NT2 TE1 = O001000 for NT1 TE1 = O00101 1 for LT TE1 = 0001 110 for ET Figure C.3/G
31、.962 - Address field format CIR EA O 2 O O Setting C.7.2.2.3 Control field The control field is a single octet shown in Figure C.4. As no dialogue occurs at layer 2, the P/F bit is always set to 1. TE1 See below EA 1 3 O Setting 8 7 6 5 4 3 2 1 Figure C.4/G.962 - Control field format Octet C.7.2.3 M
32、essage Layer (ML) The structure of a LAPD frame consists of a four-byte LAPD header and a two-byte LAPD trailer framing the maintenance channel header and data as shown below. O 4 10 2 . 64 bytes 2 LAPD FCS ML data LAPD ML header header T1308190-96 PIF 4 O O 1 O O 1 1 Setting Recommendation G.962/Am
33、d.l (06/97) 3 C.7.2.3.1 Message layer header The message layer header section follows the standard LAPD header and has the following format: Byte 1 2 3 4 5-6 7-8 9 10 Description Transmission direction Pad byte - not used Primary destination SAPI Pad byte - not used Destination descriptor Source des
34、criptor Length Pad byte - not used C.7.2.3.1.1 Transmission direction RELAY-HALF-LT RELAY-HALFNTI The transmission medium byte is set to 02H for Upstream (NT1 to ET) messages and 03H for Downstream (ET to NTI) messages. C.7.2.3.1.2 Primary destination SAPI The primary destination Service Access Poin
35、t Identifier (SAPI) is used as a router address. If the SAPI address is corresponding to one shown in Table C.5, then the destination descriptors are not read and the complete message layer information is passed on as per the routing address. If however the SAPI is not one listed in Table C.5 but is
36、 one belonging to Table 1.4, then the destination descriptor information is used. 1 FH 1 DH Table C.YG.962 - Primary destination service access point identifiers 15-12 11-6 5 -2 Routing SAPI 1 Routing address I Card type Secondary destination SAPI Position I RELAY-MIU I 21H I RELAYET I 20H I RELAY-L
37、T I 1 EH 1 RELAYNTl I 1 CH C.7.2.3.1.3 Destination descriptors The destination descriptor is encoded as a sequence of bit fields in 2 contiguous bytes. The destination card types are listed in Table C.6 called Card types. 4 Recommendation G.962Arnd.l (06/97) STD.ITU-T RECMN G-b2 AMD 1-ENGL 1997 m Li
38、Bb2591 Ob39192 122 Card MIU ASU LINE-ASU LT - ASU NTlASU ET LT NT 1 HALF-LT HALT-NT 1 LOCAL ALL-CARDS Value OOH 01H 02H 03 H 04H 05H 06H O” 08H 09H OAH OBH The secondary destination service access point identifiers can be directed to service access points. An example is given in Appendix I, Table 1.
39、4 called service access point identifiers, and can have a range of OOH to 3FH. particular applications Secondary destination The destination position is the slot number within a particular type of functional unit, such as LTs or NT1 s and can take any value from O 1 to OEH with OFH for undefined pos
40、ition. C.7.2.3.1.4 Source descriptor The source descriptor is encoded as a sequence of bit fields in 2 contiguous bytes. I Bit I Description I 15-12 Source card type (src. card) Source position (src. pos) Bearer The source card types and positions have the same definition as in C.7.2.3.1.3. Bearer i
41、s the bearer number along which the message was transmitted and can have any value between O1 and OFH. C.7.2.3.1.5 Length This byte indicates the length of the data section. The minimum length is 2 while the maximum is 64 bytes. The values are given hexadecimal format. C.7.2.3.2 Message layer data T
42、he message layer data consists of a signal definition followed by a parameter and data field. The parameter and data type fields are optional. A message layer signal may, in its own right, convey all the information required; however, in some cases, additional information may be required. In this ca
43、se, parameter data is attached to a signal. If a message has no parameter data attached, the signal consists only of the signal number as 2 consecutive bytes. In a signal with attached parameters, the parameter data follows the signal definition number. Recommendation G.962/Amd.l (06/97) 5 STD-ITU-T
44、 RECMN G.7b2 AND 1-ENGL 1997 m 4b2.571 Ob37173 Ob7 Signal name CONFIGURECHECK LT-POSITION-REQUEST NT1 - POSITION-REQUEST HALFBEARER-SUBRACK-CHECK HALF-STANDBY -SUBRACK-CHECK ET-CONFIGURE-STANDBY C.7.2.3.2.1 Signal definitions The signal definition number and associated parameters go together to make
45、 a complete message. A number of examples are given in Appendix I, Table I. 1 called Signal definitions. Currently signal definition numbers have been allocated from 0001H to 00ClH. All other signal numbers have not been allocated and are available for further enhancements or other applications. Dec
46、imal Hexadecimal number number 1 o1 2 02 3 03 4 04 5 05 6 06 C.7.2.3.2.2 Parameter descriptor The parameter descriptor describes every byte of the parameter data, A number of examples are. given in Appendix I, Table 1.2 called Parameter descriptors. Every byte can be interpreted by looking at the da
47、ta type (type entry) definition in Appendix I, Table 1.3 called Data types. NT1-CONFIGURE ALAM-P ARAMETERS APPENDIX I 10 OA 11 OB Examples of message layer data are given in Tables 1.1 to 1.4. ET - CONFIRM-CONFIGURE LT-FULL-PATCH - INDICATION - OFF LTFULL-P ATCH-INDIC ATION-ON PATCHED-BEARER-OK PATC
48、H-TO RELEASE-PATCH REQUESTPATCH 15 OF 16 10 17 11 18 12 19 13 20 14 21 15 I LTCONFIGURE-STANDBY 171 07 I I ET-CONFIGURE-NORMAL 181 08 I I LT-CONFIGURE-NORMAL 191 09 I I CARD-PRESENT I l2 I oc 1 ETCARDPOWEFXNG-UPCONFIGUE-REQUEST I l3 I OD OE I l4 I I STANDBYAVAILABLE I 22 -1 16 6 Recommendation G.962
49、/Amd.l (06/97) Table I.UG.962 - Signal definitions (concluded) Signal name STANDBY-NOT-PATCHING-THIS-BEARER STANDBY-PATCHING - THIS - BEARER CONFIGURED-HALF-STANDBY HALF-BEARER-POWERING - UPCONFIGURE-REQUEST Decimal Hexadecimal number number 23 17 24 18 25 19 26 1A Table I.2/G.962 - Parameter descriptions Parameter descriptor CONFIG-REPLYPar Param eter byte No. 1 I CONFIGURE-CHECK-Par LT-BEARER-REPORTPar I CONFIGURED-HALF-STANDBY-Par 1 1 LTtoNTl LinkAlannReport 2 NT 1 toLT LinkAlannReport 3 ETtoLT LinkAlannReport 4 NT2toNT1 LinkA IarmReport 5 NTl toNT2 LinkAlarm
