1、r CEPT T/S*SY-OBE 9 2326434 0009040 I m (3 54-08 Page E 1 Recommendation T/S 54-08 (Montpellier 1984, revised by correspondence April 1987) ISDN SUBSCRIBER ACCESS AND INSTALLATION MAINTENANCE Recommendation proposed by Working Group T/WG “Switching, Protocols and Signalling” (SPS) Text of the revise
2、d Recommendation adopted by the “Telecommunications” Commission: “The European Conference of Postal and Telecommunication Administrations, considering that ISDN subscriber access are currently being defined and are to be used for ISDN purpose, that on basis of the defined maintenance philosophy (Rec
3、ommendation T/S 50-01 i), procedures for supervision, testing measuring and maintenance need to be specified, - that the maintenance provisions associated with the ISDN subscriber access may constitute a relatively high cost factor, while the complexity of the ISDN-access requires proper maintenance
4、 support to maintenance staff, - that interworking with dedicated data networks and their maintenance procedures must be taken into account, - that the realisation of an ISDN equipment in an economic way requires large scale integrated techniques for which O also maintenance supervision should be fi
5、xed in advance, recommends that the members of the CEPT use for new digital exchanges and integrated networks the procedures for ISDN subscriber access and installation maintenance set out below.” Edition of August 15, 1987 CEPT T/S*54-08E m 232b4L4 000904L 3 m TIS 54-08 E Page 2 Contents Section 1.
6、 Reference conjiguration, general architecture for maintenance of ZSDN subscriber utcess and subscriber installation Section 2. Activities in support of maintaining the subscriber basic access controlled by the network Section 3. Activities in support of maintaining the subscriber primary rate acces
7、s controlled by the network Section 4. Section 5. Activities in support of maintaining the subscriber higher rate access Activities in support of maintaining the subscriber installation REFERENCES i CEPT Recommendation TIS 50-01. Maintenance philosophy for digital and mixed networks. 2 CCITT Recomme
8、ndation 1.41 1. ZSDN user-network interfaces - Reference configurations. 3 CCITT Recommendation 4.512. Interfaces. 4 CCITT Recommendation 1.430. Basic user-network interface - Layer I specijkation. 5 CEPT Recommendation TIS 46-20. ZSDN user-network interface data link layer specijcation. 6 CCITT Rec
9、ommendation G.821. Error performance of an international digital connection forming part of an integrated services digital network. Edition of August 15, 1987 CEPT T/S*54-OE = 2326414 O009042 5 = I I I TIC 54-08 E Section 1, Page 1 Section 1. installation Reference configuration, general architectur
10、e for maintenance of ISDN subscriber access and subscriber 1. 1.1. 1.2. 1.3. 1.4. 1.5. 2. SCOPE OF APPLICATION In this Section, reference configuration, general architecture for maintenance of ISDN subscriber access and subscriber installation are described. Also definitions of loopback mechanisms u
11、sed in this Recommendation are given. Section 2 covers the activities in support of maintaining the subscriber basic access. The functions performed by the digital transmission section and the exchange termination (ET) are identified. These functions are supervised and/or controlled by the SAMC (def
12、inition see paragraph 3.2. of Section I). Section 3 covers the activities in support of maintaining the subscriber primary rate access. The functions performed by the digital transmission section and the exchange termination (ET) are identified. These functions are supervised and/or controlled by th
13、e SAMC. Section 4 covers the activities in support of maintaining the subscriber higher rate access. The functions performed by the digital transmission section and the exchange termination (ET) are identified. These functions are supervised and/or controlled by the SAMC. Section 5 covers the activi
14、ties in support of maintaining the subscriber installation from maintenance services providers connected to the network at T Reference Points. Also, the activities in support of maintaining the subscriber installation from within the subscriber installation are specified. The D-Channel signalling pr
15、otocols which provide this activity are specified in a Recommendation on ISDN User-Network Interface protocols for Testing and Maintenance, produced by SPS/PAR. ISDN SUBSCRIBER ACCESS AND INSTALLATION CONFIGURATION The following figure shows the simplified ISDN subscriber access and installation con
16、figuration (based on CCITT Recommendations 1.41 1 2 and 4.512 3). The definitions contained in this figure are the ones used in this Recommendation. R I TA I I TE2 I DIGITAL TRANSMISSION I SECTION -m I I I I I I I h- I I I 4 I _I_) SUBSCRIBER INSTALLATION -4 I wp SUBSCRIBER ACCESS Figure 1 (T/S 54-0
17、8). Simplified ISDN Configuration. Note I. The NT2 functional grouping may be null. In this case the S and T Reference Points are coincident so that the Reference Point can be referred to as the S/T Reference Point. Note 2. The line may include a regenerator, Edition of August 15, 1987 CEPT T/S*54-O
18、E = 232b414 0007043 i T SUBSCRIBER ACCESS SUBSCRIBER I -1 I - INSTALLATION I (Note) TIS 54-08 E Section 1, Page 2 SIT I I ISDN MSP I I I I I 3. REFERENCE NETWORK CONFIGURATION AND DEFINITIONS 3.1. Basic Network Configuration The following figure is the basis for the general maintenance principles of
19、 the ISDN subscriber access and subscriber installation. SAMC: Subscriber Access Maintenance Centre. SIMC: Subscriber Installation Maintenance Controller. MSP: Maintenance Service Provider. Note. In the case where the subscriber installation does not contain a NT2, the S and T reference points are c
20、oincident. 3.2. Definitions 3.2.1. SAMC - Subscriber Access Maintenance Centre A SAMC represents a group of functions, network equipment elements and staff controlled by the Administration, which together have the responsability and capability for maintenance functions and maintenance actions within
21、 the subscriber access, such as defined in Figure 2 (T/S 54-08). The equipment and functions may be centralized or distributed in the network, local exchange and subscriber access. The precise architecture of the SAMC and internal interface(s) between SAMC staff and equipment is not a subject for th
22、is Recommendation. Conceptually, the SAMC is considered to be a functional entity within an ISDN. 3.2.2. SIMC - Subscriber Installation Maintenance Controller A SIMC represents a group of dedicated functions contained within the functional groups (as specified in 1.41 1) of the subscriber installati
23、on (i.e. TE1 and NT2) which have the following purposes: - interaction with the (human) user, - handling of maintenance protocol from the subscriber installation and/or maintenance service provider, - control of internal testing and maintenance mechanisms. It is considered that the functions of the
24、SIMC may be distributed throughout layers 1-3 and management/ maintenance entities, but the precise architecture and protocol of the SIMC is not a subject of this Recommendation. Edition of August 15, 1987 l i CEPT T/S*5V-OBE 2326414 0009044 9 m TIS 54-08 E Section 1, Page 3 3.2.3. MSP - Maintenance
25、 Service Provider i) The MSP represents a group of functions, equipment and maintenance engineering staff, which together have the responsibility for maintaining the subscriber installation or a part of the subscriber installation. A MSP cannot control the maintenance functions of the subscriber acc
26、ess. It can request a SAMC to perform these functions. Agreement and responsibility for maintenance between the subscriber and the MSP for each part or parts of the subscriber installation should be made at the time of subscription to the maintenance service (this may take the form of a commercial c
27、ontract). In any case provision to allow a customer to change the maintenance service provider(s) is recommended. The subscriber may choose not to make such an agreement with a MSP. iii) Maintenance service providers can be private providers - the Administration iv) A private maintenance service pro
28、vider is always connected to the ISDN via a recommended T Reference Point. An Administrations maintenance service provider may be connected to the ISDN via a recommended T Reference Point or via an interface which is internal (out of the scope of this Recommendation) to the ISDN. More than one MSP m
29、ay have the responsibility to maintain one subscriber installation. The responsibility for maintaining each equipment shall be unique. It is the sole responsibility of a subscriber installation and not of the network to ensure that an unauthorised MSP cannot get access to maintenance functions in th
30、e subscriber installation. ii) v) Maintenance Conditions ,for an ISDN Subscriber Access In general, an access can be considered to be in one of the following conditions for the purpose of explanation of the relationship between maintenance and trafkability in this Recommendation. An access which is
31、fully equipped, has been allocated an ISDN number(s) and is functioning correctly (meeting ail the network performance and operational requirements) is considered to be “in service”. The access can be either busy or free in this condition. An access is said to be in the “degraded transmission” condi
32、tion when the transmission of the digital section has degraded sufficiently for at least one teleservice or bearer service to cause the initiation of further maintenance activity. In this condition call offering is not changed (Le. the same as for the “in service” condition). The levels at which an
33、access enters the degraded transmission condition may be dependent on the quality of service provided to the customer. These levels are for further study and outside the scope of this Recommendation. 3.2.4.3. Out of Service due to Failure (unavailability state) When a failure exists and has been det
34、ected such that the network performance is below an acceptable limit the access is considered to be “out of service due to failure”. In such a condition call offering is attempted as normal but may not be successful and may be subsequently rejected with the appropriate clearing cause information ele
35、ments in the D-Channel protocols. Example failure conditions are: unacceptable transmission performance - access in a failure condition - failure of subscriber installation - failure of the digital transmission section - failure within individual exchange subscriber equipment - local exchange failur
36、e 3.2.4.4. Out of Service due to Operational Reasons This condition is included for information but is not considered further in this Recommendation. An Administration may wish to mark an access “out of service due to operational reasons” for example due to payment deficiencies by the customer. Call
37、 offering (either originating and/or terminating) may be rejected. Note. In any of the conditions, testing (and/or measurements) may be in progress. The availability of the access for call offering will be dependent on the specific test in progress. Whether the test or the call attempt is rejected (
38、in the case of a collision) is dependent on the specific test and/or the Administration. Further study is required. 3.2.4. O 3.2.4.1. In Service 3.2.4.2. Degrade Transmission O Edition of August 15, 1987 CEPT T/S*54-OE W 2326434 0009045 O m SUBSCRIBER T I I I I I I l INSTALLATION ISDN 71 SUBSCRIBER
39、ACCESS 1 / TIS 54-08 E Section 1, Page 4 SIT I I I 3.3. Communication Configurations 3.3.1. General The presentation of the relationships between the functional blocks SAMC, SIMC and MSP and the configurations to be maintained has been completed by figures showing the various communication paths. Th
40、e communication paths are shown by bold lines within the following figures. Communication Configuration for Maintenance of a Subscriber Access by the SAMC 3.3.2. b- NETWORK -4 I I Configuration I to be 4 I I maintained Figure 2a (T/S 54-08). Y- SAMC: Subscriber Access Maintenance Centre. SIMC: Subsc
41、riber Installation Maintenance Controller. MSP: Maintenance Service Provider. Edition of August 15, 1987 CEPT T/S*54-OBE m 2326414 0007046 2 m TIS 54-08 E Section 1. Page 5 3.3.3. Communication Configuration for Maintenance of a Subscriber Access by an SAMC, requested by an MSP Test req/resp (see No
42、te) / T SIT I I I I I l I I I SUBSCRIBER INSTALLATION MSP ,Test req/resp I (see Note) I a- to be -d Configuration I I maintained Ir- NETWORK pH Figure 2b (T/S 54-08). SAMC: Subscriber Access Maintenance Centre. SIMC: Subscriber Installation Maintenance Controller. MSP: Maintenance Service Provider.
43、Note. Test requests and/or responses are made by normal calls or automatic procedures. Protocols for the automatic procedure are to be defined. The MSP has no direct control over subscriber access maintenance. The SAMC tests the subscriber access according to other sections of this Recommendation. E
44、dition of August 15, 1987 CEPT T/S*54-O8E W 232b4L4 0009047 4 W SUBSCRIBER T I INSTALLATION 1 TIS 54-08 E Section 1, Page 6 SUBSCRIBER 3.3.4. Communication Configuration for Maintenance of a Subscriber Installation by an MSP within the ISDN I A OOC 1- I I II I I I L II I I I I Configuration I I 6 to
45、 be -4 I maintained I k- NETWORK -d Figure 2c (T/S 54-08). SAMC: Subscriber Access Maintenance. Centre. SIMC: Subscriber Installation Maintenance. Controller. MSP: Maintenance Service Provider. Edition of August 15, 1987 CEPT T/S*54-O8E 2326434 0009048 b = TIS 54-08 E Section 1, Page 7 3.3.5. Commun
46、ication configuration for Maintenance of a Subscriber Installation by an MSP connected to the ISDN via a T Reference Point O Communication T I “I! SUBSCRIBER SUBSCRIBER INSTALLATION - II I I ACCESS Il I I I SIMC I I I I! ISDN I l I f 1 Configuration I A- tobe -A O i maintained i NETWORK -4 Figure 2d
47、 (T/S 54-08). SAMC: Subscriber Access Maintenance Centre. SIMC: Subscriber Installation Maintenance Controller. MSP: Maintenance Service Provider. 3.4. Types of Loopback This chapter defines the terminology used in specifying the characteristics of loopbacks. The “loopback point” is the location of
48、the loopback. The “control point” is the location from which activation/deactivation of the loopback is controlled. Note. The generation of the test pattern used over the loopback may not be located at the control point. The following three types of loopback mechanisms are defined: (a) Complete loop
49、back-a complete loopback is a layer 1 mechanism which operates on the full bit stream. At the loopback point, the received bit stream shall be transmitted back towards the transmitting station without modification. Note. The use of term “complete loopback” is not related to implementation since such a loopback may be provided by means of active logic elements or controlled unbalance of a hybrid transformer, etc. At the control point access to point only the information channels may be available. (b) Echoing loopback-an echoing loopback is a layer 1 mec
