1、CCITT RECMN*M.3602 92 E 4862CL O579094 8b8 INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMM ITTEE MAINTENANCE: ISDN M.3602 (1 0/92) APPLICATION OF MAINTENANCE PRINCIPLES TO ISDN SUBSCRIBER INSTALLATIONS Recommendation M.3602 CCITT RECMN*M*3602 9
2、2 4862593 0579095 7T4 H FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCIT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a
3、 view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies i
4、s covered by the procedure laid down in CCI?IT Resolution No. 2 (Melbourne, 1988). Recommendation M.3602 was revised by Study Group IV and was approved under the Resolution No. 2 procedure on the 5th of October 1992. CCIT NOTE In this Recommendation, the expression ?Administration? is used for conci
5、seness to indicate both a telecommunication administration and a recognized private operating agency. 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 permissi
6、on in writing from the ITU. CCITT RECMN*M*3602 72 4862573 0577076 630 Recommendation M.3602 APPLICATION OF MAINTENANCE PRINCIPLES TO ISDN SUBSCRIBER INSTALLATIONS (Melbourne 1988 as Rec. 1.602; revised and renumbered in 1992) Abstract This Recommendation defines physical layer maintenance functions
7、used to maintain ISDN subscriber Keywords - ISDN; - maintenance: - subscriber installation. installations. 1 Scope of application This Recommendation presents the possible elementary functions for the maintenance of the subscriber installation. The functions are to be considered as optional, except
8、when needed to meet specific network interface requirements found in Recommendations 1.430 3 and 1.431 4. These functions can be controlled by the local side, (e.g. from the subscriber premises) and by a remote side (i.e. from a Management Service Provider) (MSP) as described in Recommendation M.360
9、0 i. It is the responsibility of the subscriber installation to ensure that only authorized MSPs are given access to the functions covered by this Recommendation. 2 Network configuration for maintenance activities Figure 1h4.3602 is the basis for the general maintenance principles of the ISDN subscr
10、iber installation. There are several subscriber configurations using primary rate shown in Figure 2M.3602 that can appear behind any of the NTls shown in Figure 2h4.3604 6. The first is the simplest case of separate NT1 and NT2 followed by a primary rate TE. Another case is with the NT1 and NT2 comb
11、ined into one unit. A third case is an NT2 that is a PABX with several basic rate TES behind it. A final case is one in which the NT2 is a multiplexer with several basic rate TES behind it. 3 Automatic supervision 3.1 3.1.1 General Continuous automatic supervision on layer 1 This supervision may be
12、realized by permanent automatic mechanisms located in the pieces of equipment of the subscriber installation (see definition in Figure 1M.3602). These automatic mechanisms are operational during the active period of the subscriber basis access. They are designed to detect malfunctioning of particula
13、r items, e.g. power supply, quality level of transmission, incoming signai, frame alignment. This Recommendation deals only with the maintenance aspects of management. Recommendation M.3602 (10/92) 1 r- 1T- a) I Subscriber !+I Subscriber access I installation I S T I I NTl TE NT2 Configuration 4 9 t
14、o be maintained k s- 1 TE NT2 + NTI MSP Management Service Provider OAMC Operation Administration Maintenance Centre SAMF Subscriber Access Management Function SIMF Subscriber Installation Management Function See Recommendation M.3600 I for a detailed discussion of these terms. Note - In some countr
15、ies, certain maintenance functions within the subscriber access are controlled by the subscriber installation (SIMF). FIGURE 1m.3602 Configuration for the maintenance of the subscriber installation c) (PABX) TE . ci I I I TE TO40325O-Q2/w2 FIGURE 2m.3602 Primary rate subscriber configuration example
16、s 2 Recommendation M.3602 (10B2) CCITT RECMN*M=3602 72 H 4862573 0577078 403 3.1.2 Subscriber installation functions The following functions may be supervised - monitoring of operation functions within the subscriber installation (e.g. power supply); - supervision of information related to or receiv
17、ed from the digital transmission section. 3.2 Automatic supervision on layer 2 and layer 3 of the D-channel protocol This activity covers supervision on layers 2 and 3 of the D-channel protocol. Automatic supervision on layers 2 and 3 may be made by self-acting mechanisms implemented in the subscrib
18、er installation. There are three categories of automatic supervision which may be performed by layer 2 and layer 3 of the D-channel protocol: - service provision incapability detection (e.g. detection of incapability of layer 2 to establish a data link connection); - protocol misoperation detection;
19、 - error monitoring (e.g. layer 2 CRC check procedure can detect the occurrence of an errored frame). These events may be recorded as discussed in Recommendation M.3640 2. 4 Internal tests 4.1 Internal test of the TE1 and TA Some of the TEs/TAs may manage internal tests for all or parts of their fun
20、ctionalities. The internal tests may be activated either automatically by the TE and TAS or by a local command in the TE and TAS or by a remote request. Some of these tests are dependent on the terminal type. Such tests shall not affect the user-network interface, i.e. no test signais shall be trans
21、mitted across the interface when a test is in operation. The terminal equipment may have the ability to abort an internai test sequence, for example, in case of an incoming call attempt. If this test has been requested by an MSP, the subscriber installation should report the discontinuance of the te
22、st to the requesting MSP. The result of an internal test procedure execution should be either passed or failed, and in the latter case an additionai diagnostic information may be given. 4.2 Internal test of the NT2 The subscriber should have facilities which can help to verify that the subscriber in
23、stallation is not affected by a fault. Definitions of these procedures and functions require further study. The functionalities may be similar to the ones presented for the TE and TA in 0 4.1. The following internal tests of the NT2 have been identified: Recommendation M.3602 (10192) 3 CCITT RECMN*M
24、.3602 92 13 Li862591 0579099 34T 4.2.1 Continuity test The objective is to verify that the internal S interfaces of the NT2 can be activated. The mechanism which is implemented in the NT2 could be based on a normal activation of the layer 1 of the interfaces. The principle for such a test is the sam
25、e as the one defined for the local exchange function (see Recommendation M.3603 5, 0 3.3). 4.2.2 S interface check using loopback 3 The loopbacks are shown in 4 7. The results could be used for fault localization, particularly in the case where the NT2 functions are distributed. 4.2.3 Test call to t
26、he terminal equipmentfrom the hT2 An NT2 may address one particular terminal equipment of the installation. Thus, it easily controls a test call. This procedure would allow the NT2 to verify the connection of the TE or TA to the installation and also to check layers 1.2 and 3 operating conditions (e
27、.g. response time supervision). The test call could be initiated by the SIMF at the request of an MSP. The test call could be a normal call made for maintenance purposes. 4.3 Basic rate subscriber installation functions using S- and Q-channels The S- and Q-channels of the T interface (see Recommenda
28、tion 1.430 3) may be used to perform functions supporting failure detection and fault location. These functions can be grouped into four major areas. 4.3.1 Loss ofpower indication The NTl or NT2 may use the S-channel to indicate a loss of power and the TE may use the Q-channel to indicate a loss of
29、power. The use of these indications on interfaces using the activatioddeactivation procedure is for further study. 4.3.2 Self-testfunctions The Q-channel may be used to request an NT1 or NT2 to perform a self-test. The S-channel may be used to indicate that the self-test is being performed and to in
30、dicate whether the test passed or failed. 4.3.3 Loopback control The Q-channel may be used to control loopbacks C in the NTls or loopbacks BI in NT2s. The S-channel may be used by the NTl or NT2 to indicate that the loopback is active. 4.3.4 Detected access transmission system error and loss of rece
31、ive signal The S-channel may be used to indicate that the NT1 cannot properly identify the signal received from the network. It may also be used to indicate that the NT1 has received an indication of a transmission abnormality from the network. 5 Test call from the MSP Under study. 4 Recommendation
32、M.3602 (10192) CCITT RECMN*V-3602 72 BI 4862573 0577100 771 II 6 Call to a test responder from the subscriber installation The MSP may provide test responders that are accessed via normal call procedures. There may be test responders for various teleservices and bearer services. The selection of the
33、 service involved with the test call is made using the lower-layer and higher-layer compatibility information elements as defined for the normal cai1 control procedures. 7 Loopbacks 7.1 Locations of Eoopbacks associated with the subscriber installation Loopback locations for fault localization and v
34、erification are shown in Figure 3M.3602. 5 A4 Note -For an explanation of 3,4,5, A, BI , band C, see Tables 1M.3602 and UM.3602. FIGURE 3m.3602 Loopback locations associated with the subscriber installation CCITT RECMN*M-3b02 92 48b259L 0579303 828 Loopback type Control Control point mechanism NT2 N
35、T2 NT2 Local maintenance (Note 2) Layer 3 Local maintenance (Note i) 1.2 Loopback characteristics for basic rate subscriber installations Characteristics of loopbacks are given in Table 1M.3602. TABLE 1A4.3602 Characteristics of loopback mechanisms for basic rate su-scriber installations implementat
36、ion Loopback Channel(s) looped back 2B + D Location 3 In NT2, as near as possible to S reference point, towards T (Note 7) Optional Optional Complete, transparent or non-transparent In TA or TE towards S Bi, Bz (Note 3) Partial, transparent or non-transparent 4 5 Bi, B2 Partial, transparent or non-t
37、ransparent Optional Optional In TA, as near as possible to R reference point towards s In NT1, toward the T reference point Bi, B2 (Note 3) Partial, transparent or non-transparent C Layer 1 (Note 4) (Note 5) Bi In NT2, as near as possible to S reference point (Note 6) Optional Optional Optional Part
38、ial, Layer 1 or transparent or Layer 3 non-transparent Bz In NT2, as near as possible to T reference point hese loopbacks are used as part of an optional internal test. When used, no information should be sent toward the network interface (Le. INFO O is transmitted to the interface). A In the TE tow
39、ards user Nute I -This loop might also be controlled by signalling in the B-channel as specified in the X- and V-Series Recommendations. Nute 2 - Loopback 3 may be used as part of an NT2 self-test. The selft-test may be remotely requested by an MSP. Note 3 - The B1 and B2 channel loopbacks are contr
40、olled by separate control signals. However, both loopbacks may be applied at the same time. Note 4 - An exchange of layer 3 service messages may take place between TE (or NT2) and the exchange prior to the use of the layer 1 control mechanism. However, there are situations where the TE (or NT2) may
41、not receive a reply: a) b) The definition of layer 1 control signal from TE (or NT2) towards NT1 (based on the use of the optional multi-frame) is the message may not be transmitted when the interface is in a fault situation; a network that does not support the layer 3 signalling option, need not re
42、spond. for further study. Note 5 - The network controls the loopback by overhead in the transmission system. Note 6 - Loopback Bi is applied at each individual interface at reference point S. Note 7- Also see Table 1M.3603 5 for other loopbacks in the NT2. 6 Recommendation M.3602 (10192) CCITT RECMN
43、*M.3b02 92 4862593 0579302 764 I Channel(s) looped back Loopback type Control point 7.3 Loopback characteristics for primary rate subscriber installations Characteristics of loopbacks are given in Table 2M.3602. TABLE 2M.3602 Characteristics of optional loopbacks for primary rate access Control mech
44、anism Implementation Location Loopback 3 4 C Bl B2 A In NT2, as near as possible to S reference point, towards T (Note 8) 23B+Dor 24 B channels (Note 4) 30 B + D or 31 B channels (Note 5) Complete, non-transparent (Note 7) NT2 Local maintenance (Note 6) Optional In TA or TE towards S B, Ho, Hi (Note
45、 3) Partial, transparent or non-transparent NT2 Layer 3 Optional In NT1, towards the T reference point 23B + D or 24 B channels (Note 4) 30B +Dor 31 B channels (Note 5) Complete, non-trau sparent (Note 7) TE. NT2 Layer 1 (Note 1) Optional Partial, transparent or non-transparent TE. NT2 Layer 1 or La
46、yer 3 Optional In NT2, as near as possible to S reference point (Notes 2 and 8) In NT2, as near as possible to T reference point Optional These loopbacks are used as part of an optional internal test. When used, normal signal should be sent toward the network interface. In the TE towards user Option
47、al I Note I -Transfer of layer 3 service messages may take place between TE (or NT2) and the exchange prior to the use of the layer 1 control mechanism. However, there are situations where the TE (or NT2) may not receive a reply: a) b) Definition of layer 1 control signals from TE (or NT2) towards N
48、Tl remains for further study. the message may not be transmitted when the interface is in a fault situation; a network that does not support layer 3 signalling option need not respond. Nore 2 - Loopback B 1 is applicable to each individual interface as reference point S. Note 3 - The different B, Ho
49、 and Hi channel loopbacks are controlled by separate control signals. However, several per channel loopbacks may be applied at the same time. Note 4 - For 1544 kbis interface. Note 5 - For 2048 kbis interface. Nute 6 - Loopback 3 may be used as part of an N2 self-test. The self-test may be remotely requested by an MSP. Note 7 - These loopbacks are normally non-transparent and send AIS in the forward direction. However, these loopbacks may be transparent. When transparent loopbacks are used, the device at the loopback point must ensure that the forward
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