1、- STD-ITU-T RECMN Q.753-ENGL 1997 M 48b257L Ob384bl 3OLl m INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.753 (06/97) SERIES Q: SWITCHING AND SIGNALLING Specifications of Signalling System No. 7 - Signalling System No. 7 management Signalling System No.
2、 7 management functions MRVT, SRVT and CVT and definition of the OMASE-user ITU-T Recommendation Q.753 (Previously CCITT Recommendation) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORK1 NG FUNCTION
3、S AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 CLAUSES APPLICABLE TO
4、ITU-T STANDARD SYSTEMS General Message transfer part (MTP) Signalling connection control part (SCCP) Telephone user part (TUP) ISDN supplementary services Data user part Q.I-Q.3 Q.4-Q.59 Q. 60-Q. 99 Q.100-Q.119 Q. 120-Q.249 Q.250-Q.309 Q.400-Q.499 Q. 500-Q. 599 Q.600-Q.699 Q.700-Q.849 Q.700 Q.701-Q.
5、709 Q.711-Q.719 Q. 720-Q. 729 Q.730-Q.739 Q. 740-Q. 749 II Signailing System NO. 7 management (2.750-Q.759 ISDN user part Transaction capabilities application part Test specification Q3 interface DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE
6、 SYSTEMS INTELLIGENT NETWORK BROADBAND ISDN Q. 760-Q.769 Q.770-Q.779 Q.780-Q.799 Q .800-Q .849 Q.850-Q.999 Q. I 000-Q. 1 O99 Q. I 1 OO-Q. 1 1 99 Q. I 2004.1 999 Q.2000-Q.2999 For further details, please refer to ITU-T List of Recommendations. STD-ITU-T RECMN Q.753-ENGL 1777 48b2571 Clb384b3 187 ITU-
7、T RECOMMENDATION Q.753 SIGNALLING SYSTEM No. 7 MANAGEMENT FUNCTIONS MRVT, SRVT AND CVT AND DEFINITION OF THE OMASE-USER Summary This Recommendation contains the informal text descriptions of the functions MRVT (MTP Routing Verification Test), SRVT (SCCP Routing Verification Test) and CVT (Circuit Va
8、lidation Test), as well as the definition of the OMASE-User process containing the logic of these functions at a node. The MRVT is a function started at a node by management action (defined in the MRVT managed object of Recommendation Q.751.1), which uses the SS No. 7 network to perform an MTP routi
9、ng audit. The SRVT is an analogous function for the SCCP. The CVT ensures consistency of data and physical connection for the signalling points at each end of an ISDN User Part or Telephony User Part trunk circuit. The main revisions to the 1993 version of this Recommendation are: a) enhancement of
10、the compatibility rules and definition of a mechanism to transfer b) c) d) e) unrecognized parameters transparently; an extension to the MRVT to provide route priority information; addition of an explicit check on the maximum allowed number of MRV Tests, and SRV Tests, at a node at any time; revisio
11、n of the MRVT text; addition of an ASN. 1 module and mapping of primitives to allow management control. Source ITU-T Recommendation Q.753 was revised by ITU-T Study Group 11 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 5th of June 1997. FOREWORD ITU (International Te
12、lecommunication 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. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on
13、 them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The appro
14、val of Recommendations 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, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, th
15、e expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a cla
16、imed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the
17、ITU hadhad not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 199
18、7 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 permission in writing from the ITU. 11 Recommendation 4.753 (06/97) 1 2 2.1 2.2 2.3 2.4 2.5 3 3.1 3.2 4 4.1 4.2 CONTEN
19、TS Introduction MTP management functions . General . Network routing management - MTP Routing Verification Test (MRVT) . 2.2.1 General procedure considerations . 2.2.2 The MRVT messages 2.2.3 2.2.4 The MRVT procedure . Initiation of the MRVT procedure at a signalling point Reception of a message for
20、 an unknown destination . Timer definition and values 2.4.1 MRVT timers 2.4.2 Performance time definitions and values OMAP model for MRVT . 2.5.1 Mapping of primitives . 2.5.2 State transition diagrams for MRVT - Logic in the OMASE-User SCCP management functions . General . Network routing managemen
21、t - SCCP Routing Verification Test Requirements upon an SCCP Routing Verification Test (SRVT) Specific SCCP Routing Verification Tests . OMM model for SRVT . 3.2.1 3.2.2 3.2.3 Circuit management functions General . Circuit Validation Test (CVT) 4.2.1 The test 4.2.2 CVT State Transition Diagrams Anne
22、x A A . 1 Detailed model of the OMASE-User A.2 MIS-User to management process interface . Annex B . B . 1 Example of successful MRVT B.2 B.3 Example of “unknown initiator“ response with copyData parameter Example of unsuccessful test (STP X does not know initiator I) . Page 1 2 2 2 3 5 8 8 13 14 14
23、14 15 15 16 20 20 20 20 20 31 37 37 38 38 40 48 48 45 51 51 55 55 . Recommendation 4.753 (06/97) 111 Recommendation Q.753 SIGNALLING SYSTEM NO. 7 MANAGEMENT FUNCTIONS MRVT, (revised in 1997) SRVT AND CVT AND DEFINITION OF THE OMASE-USER 1 Introduction This Recommendation contains the informal text d
24、escriptions of the functions MRVT, SRVT and CVT, the semi-formal description of the OMASE-User SDL and primitive mapping. The name MRVT stands for “MTP Routing Verification Test“, SRVT stands for “SCCP Routing Verification Test“, and CVT stands for “Circuit Validation Test“. These functions require
25、the resource modelled by the managed object at the initiating Signalling Point (SP) to communicate with similar resources at other SPs, using the Signalling System No. 7 network and protocol, in order to audit certain SS No. 7 data. The network is also checked in these audits on its use of this data
26、. See Figure 1 for an illustration of the OMAP model for these functions. In this Recommendation, the informal text description of the complete function as seen external to the signalling point is followed by a semi-formal description (including a mapping of primitives between OMASE-User and OMASE,
27、and SDL for the OMASE-User) of the OMASE-User. The logic in these functions is assumed to be located in the OMASE-User; the Management Process provides the mapping between the Signalling Point Management and the OMASE-User; and the communication functions reside in OMASE. For a definition of OMASE,
28、see Recommendation Q.754. Recommendation 4.753 (06/97) 1 STDmITU-T RECMN Q.753-ENGL 1777 YBb259L Ob384b7 822 1 . . . 1, t 2, Y. I SCCP I l MTP 3 I l MTP 2 I l MTP 1 I T1136550-91 Figure UQ.753 - Application layer and application process model 2 MTP management functions 2.1 General At present, the on
29、ly function defined here for managing the MTP is the MRVT. 2.2 The MTP routing verification test requirements are as follows: a) b) Independence from linkset failures. c) d) e) Network routing management - MTP Routing Verification Test (MRVT) Independence fi-om MTP routing policy. To use the existin
30、g MTP without modifications. To respond to all tests (positive or negative). Independence from the network structure (but note that the test has not been examined yet to see if it is suitable in broadband networks -this is for frther study). 2 Recommendation Q.753 (06/97) f) The procedure should: -
31、- detect excessive length routes; - detect loops in MTP routing; detect unknown destinations (i.e. non-existent destinations, missing routing entries and routing comptions); check the bidirectionality of signalling relations (Le. if SP A can reach SP B, can SP B reach SP A?). Note that the test migh
32、t need extending to cater for asymmetrical routes, and for ping-pong loops if TFP messages are lost. - 2.2.1 General procedure considerations The object of the MTP routing verification test is to determine if the data of the MTP routing tables in the network are consistent. It is based on a decentra
33、lized test procedure using test messages. It will follow all possible routes to reach the test destination, while tracking the identities of STPs crossed. In defining the MRV Test for a particular network, the following points should be considered: a) b) cl d) Inter-network operator agreements are r
34、equired if the test is to traverse inter-operator MTP boundaries. If there is network congestion, the MRV Test should be m (if at all) with circumspection to avoid overload of the network. The MRVR trace on success should only be used if essential. The value of timer T, could be increased if the pri
35、ority of the MRV Test is low at the nodes of the network. This approach requires discretion: T, should be short enough to give a true picture of the networks routing, but long enough to provide a low message frequency. The test is started in any point (SP or STP) for any destination which is in the
36、MTP routing tables and is stopped at the test destination or any intermediate SP at which an error is detected. The test will check the complete routing in the network only if all intermediate signalling points have routing information for the initiator and for the test destination and no errors are
37、 detected at intermediate SPS. When an inconsistency or failure is detected, local actions are as specified. The initiator of the test is alerted. The MRVT procedure is applied to individual MTP routing tables. In terms of Recommendation Q.751.1, the managed items involved in the MRVT procedure are
38、SignRouteSetNePart instances contained in the same mtpSignPoint as the mtpRouteVerifT est instance and the signRouteNePart instances contained in these SignRouteSetNePart instances. An “accessible signalling point/initiator/destination“ mentioned in this Recommendation is a signRouteSetNePart instan
39、ce, representing that destination, whose operationalstate attribute has the value “enabled“. An “available route“ mentioned in this Recommendation is a signRouteNePart instance whose operationalstate attribute has the value “enabled“. The words “there is routing information for a signalling point“ o
40、r “known signalling point/initiator/destination“ mentioned in this Recommendation means that a SignRouteSetNePart instance representing that signalling point exists. If the MTP is to use structured routing tables (e.g. some or all of the entries in the routing tables may refer to sets of point codes
41、), then the procedure (andor its initiation) is for further study. Recommendation 4.753 (06/97) 3 2.2.1.1 The procedure in 2.2.4.1 should be started on demand (under conditions determined by the network operator) from local maintenance staff or an operations centre when, for example: a) New MTP rout
42、ing data are introduced. Each signalling routeset should pass the MRVT procedure successfully before being opened to traffic. b) MTP routing data are changed. cl An unexpected MRVR (due to unknown signalling point, see 2.3) is received. d) Measurement 5.5 of Recommendation Q.752 indicates a signific
43、ant routing problem. In cases c) and d) above, the traceRequested parameter of the MRVT message should be set to indicate no detailed information is expected. Starting an MRV Test on receipt of an unexpected MRVR message (indicating “unknown Destination Point Code“) requires consideration - subclaus
44、e 13.2.2 iiUQ.704 defines sending a transfer prohibited message from a signalling transfer point Y relating to a destination X when Y is unable to transfer messages to X. If Y has no routing data for X, routeset tests to Y for the unknown destination X might be started by the recipient of the transf
45、er prohibited message. The MRV Test could be used to diagnose the errors in the routing table; the MRVR message which triggered the test indicates that any routeset tests started on receipt of related transfer prohibited messages should be stopped, e.g. by manual intervention. Running the MRVT proce
46、dure at a signalling point 2.2.1.2 Definitions in the MRVT The notion of an MTP route is defined in B.l.2.8/Q.75 1.1. A hop of an MTP route is the combination of signalling point and adjacent signalling point in the routes ordered sequence of SPs. The parameter “pointCodesTraversed“ contains a list
47、of the SPs encountered by successive MRVT messages along one path from the test initiator SP to the tested destination. The first entry in this list is the test initiator. The optional parameter “routePriorityList“ is a list of elements, arranged in the same order as pointCodesTraversed, each elemen
48、t is the priority of the route at the corresponding signalling point to the test destination. Thus, if the value of pointCodesTraversed is SPI, SP, , , SP, in an MRVT message sent out fiom SP, the value of routePriorityList is pi, p, ., p, where pi is the priority at SP, of this route through SP, to
49、wards the test destination. By “priority pi of the route“ is to be understood the order of the linkset (fiom SP, to Spi+,) in the route selection at SP, to the test destination (see clause 4/Q.704). 2.2.1.3 The network operator might construct routing tables which contain paths indicated by the MRV Test as loops, but such paths will never be followed by any MSU (because certain hops in the path will not be available at the same time as others, whatever link failures there are in the network). In order for such “pseudo-loops“ never to become real loops, network implementatio
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