1、CCITT RECMN*M-3640 92 H 4862593 0577407 LO4 m INTERNATIONAL TELECOMMUNICATION UN ION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE MAINTENANCE: ISDN M.3640 (1 0192) MANAGEMENT OF THE D-CHANNEL - DATA LINK LAYER ANDNETWORK LAYER Recommendation M.3640 COPYRIGHT International T
2、elecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesCCITT RECMN*M-3640 92 4862591 0577408 040 FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is res
3、ponsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCIT which meets every four years, establishes the topics for study and approves Recommendations prepared
4、by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). Recommendation M.30 was prepared by Study Group IV and was approved under the Resolution No. 2 procedure on the 5
5、th of October 1992. CCIIT NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized private operating agency. O ITU 1993 All rights reserved. No part of this publication may be reproduced or utilized in a
6、ny form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU, COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesCCITT RECMN*N=3640 92 = 4Bb259L 0577409 TB7 W Recommend
7、ation M.3640 MANAGEMENT OF THE D-CHANNEL - DATA LINK LAYER AND NETWORK LAYER (I 992) A hstruct This Recommendation contains a prosaic description of the management aspects of the data link layer and Keywords - fault Management; - performance management; - management of ISDN D-channel; - management o
8、f ISDN. network layer of the access to ISDNs. Besides it also defines managed objects, by using OSI-management principles. 1 Introduction The purpose of this Recommendation is to describe the management capabilities) for the data link (layer 2) and the network (layer 3) layer associated with the acc
9、ess to Integrated Services Digital Networks (ISDNs). These management capabilities are specified as functions in the Exchange Termination (ET). These functions may either be visible to an TMN Operations System (OS) via a Q-interface or visible to local maintenance personnel via an F-interface. The p
10、rinciples of Recommendation M.20 3 and M.3600 Series Recommendations 5, 6 are adhered. This Recomtnendation pertains to management of the data link layer and network layer of the access- protocols between the exchange termination (ET) and subscriber installation (see Figure l/M.3640). The management
11、, as viewed only by the ET of the data link and network protocols, is specified. Section 2 provides definitions of terms introduced in this Recommendation. Section 3 outlines a reference configuration for management of the data link layer and network layer. In section 4 a prosaic description is give
12、n of the capabilities for management of the data link layer and network layer. In section 5 a list of abbreviations is given. In Appendix II, an informal description of the management information is given. Appendix III gives the semi-fomal specification of the candidate managed objects for the data
13、link layer and network layer of the D-channel. In Annex A, the management support functions are referenced. Appendix I lists the management capabilities which are to be considered to be included in future versions of this Recommendation. 2 Definitions 2.1 autonomous management The management operati
14、ons which are local to the network element and which are not controlled by an external operations system or by a human operator. Autonomous management operations are supported by internal mechanisms which monitor a certain object and which decide by analysing the results of the monitoring which acti
15、on should be implemented. The whole process is automated. I) Management capabilities refer to operation, maintenance and administration and also to e.g. configuration and performance management and possibly other management areas. Recommendation M.3640 (10D2) 1 COPYRIGHT International Telecommunicat
16、ions Union/ITU TelecommunicationsLicensed by Information Handling Services CCITT RECMN*M-3640 92 48b259L O577410 7T9 Layer 3 Layer 2 Layer3 4- Layer2 + 2.2 human machine interface The management operations which are locally performed by a human operator. These operations are visible at the F-interfa
17、ce of TMN. 2.3 management information Management information refers to the management view of resources. This management view consists of the management characteristics of the resources, the actions which may be performed upon the resources and the notifications which may be emitted, due to internal
18、 events. 2.4 managed object See ISO/IEC 749814. 2.5 attributes See Recommendation X.7 10. 2.6 systems management operations See CCITT Rec. X.701 I ISO/IEC 10040. 2.7 notification See CCITT Rec. X.701 I ISOAEC 10040. 2.8 invalid frame See Q 2.9 of Recommendation Q.921. b Layer3 b Layer2 - 3 Reference
19、 configura tion for management of the access protocol The ISDN-access protocols are defined between the ISDN and the user (see Figure 1M.3640). The protocol entities of the data link layer and network layer are located in the exchange termination (ET) and in the subscriber installation (Si). The SI
20、is composed of the terminal equipment (TE) and/or the network termination type 2 (NT2)2). The ET is part of an ISDN local exchange. Layer 1 Layer 1 User Subscriber installation ISDN Exchange termination FIGURE 1/M.3640 Peer relationships between the exchange termination and subscriber installation 2
21、, In the United States-standards the NTi will also be part of the SI. However, this has no effect on this Recommendation. 2 Recommendation M.3640 (10/92) COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling ServicesCCITT RECNN*fl.3640 92 D 4862591 0
22、577411 635 m MIS-user (agent role) In Figure 2M.3640, a reference configuration for management of the access protocol is presented. This reference configuration is a refinement of Figure 9M.3600 and is based upon the Telecommunication Management Network (TMN) concept (see Recommendation M.3010) 4. T
23、MN defines a structure which contains, among other things, Operations Systems (OSs) and Network Elements (NEs). In this Recommendation, the ISDN local exchange is considered to be the NE. The interface between the OS and NE is, in TMN-terminology, called the Q3-interface. ISDN local exchange (manage
24、r role) I Q3 I Operation! Operations Notifications I 7 Managed object representing the aspects of the 0 management o D-channel Local mapping T04034M-91 Id02 FIGURE 2/M.3640 Reference configuration for management of the access protocol Management of a communication environment is an information proce
25、ssing application. Because the environment being managed is disuibuted, the individual components of the management activities are themselves distributed. The interactions which take place between management applications (manager and agent) are abstracted in terms of operations and notifications iss
26、ued by one entity to the other. The management activities are effected through the manipulation of managed objects. These managed objects are the management view of a system resource that is subject to management, such as a data link layer entity. Thus, a managed object is the abstracted view of suc
27、h a resource that represents its properties as seen by and for the purposes of management. With the definition of managed objects the possible management activities are described. The local mapping of the managed objects upon the resources they represent is a matter of implementation 1 and is not su
28、bject to standardization. For a more detailed description of the concepts of OSI-management and TMN, see CCITT Rec. X.701 I I ISO/IEC DIS 10040 and Recommendation M.3010. 1 i Recommendation M.3640 (10192) 3 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Informatio
29、n Handling ServicesCCITT RECHN*M-3640 92 4862573 0577432 571 4 Prosaic description of management of the data link layer and network layer This section provides a prosaic description of the management capabilities relevant to management of the data link layer and network layer of the D-channel. The d
30、ata link layer and nework layer peer relationships considered here are the signalling data on the D- channel and packet data on the D-channel. The management capabilities include the following management functions: - counts (with associated thresholds) for performance monitoring; - counts (and assoc
31、iated thresholds) or logs for protocol abnormalities; - an on-demand log of all protocol activity on a given D-channel over a specified time interval; - the counters for the performance monitoring and protocol abnormality parameters shall be readable and resettable on demand; - other support managem
32、ent functions are listed in Appendix III. 4.1 Management information relating to the datu link layer In the data link layer, several entities have been identified. See Figure 3/M.3640. i Physical I layer I I I I User 4+b Network 0403430-wmo3 ID request, ID verify request, ID check response ID assign
33、edldenied, ID check request, ID remove MDL-ERROR indication MDL-XID command MDL-XID response request TE1 removacheck procedure MDL-ASSIGN-REQUEST, MDL-REMOVE-REQUEST Note - For abbreviations see 5. FIGURE 3lM.3640 Composition of layer 2 4 Recommendation M.3640 (10192) COPYRIGHT International Telecom
34、munications Union/ITU TelecommunicationsLicensed by Information Handling ServicesCCITT RECMN*M*3640 92 m 4862593 0577433 408 m 4. I. 1 Protocol error detection and logging The following data link layer errors shall be logged per D-channel: i) 2) 3) 4) 5) 6) 7) 8) 9) the frames received with a contro
35、l field that is undefined or not implemented; the frames received with an information field that is not permitted; the supervisory or unnumbered frame with incorrect length; the frames received with an invalid receive sequence number .e. invalid N(R); the frames received with an information field th
36、at exceeds the maximum established length; the Frame Reject (FRMR) frames received; the Disconnect Mode (DM) frames in response to a Set Asynchronous Balanced Mode Extended (SABME) frame3); the proper responses (i.e. unnumbered acknowledgement or disconnect mode frames) not received to establish or
37、restore the link after N200 SABME frames were sent; the DM frames sent in response to a SABME frame. 4.1.2 hyer 2 performance monitoring specify measurements for these counters, for which scheduling is allowed): The ET shall keep counts for the following layer 2 parameters for each D-channel (it is
38、optionally possible to - - - - The occurrence of invalid frames (see 0 2.9 of Recommendation Q.921); except those with FCS-errors are the number of frames with Frame Check Sequence (FCS) errors at the ET; the total number of fr,mes received at the ET; the number of frames retransmitted by the ET; th
39、e tot number of frames transmitted by the ET. counted per D-channel or logged. The unexpected frames (see Table 9/Q.921) are logged. 4.2 Management information relating to Recommendation Q.931 This subsection describes the management information of the basic call control function of the network laye
40、r. Both the opportunities and the requirements are listed here. 4.2.1 Incorrect messages The messages defined for layer 3 in 0 5.8 of Recommendation Q.931 should obey specified rules. The error conditions are handled by the protocol itself. In Recommendation Q.931 a number of message faults are defi
41、ned. For instance, a message may contain an information element which represents an invalid bearer capability (or a missing bearer capability information element). The following incorrect messages are defined in Recommendation Q.93 1 : - messages received containing a protocol discriminator coded ot
42、her than “Q.931 user-network call control message” (see 0 5.8.1 of Recommendation Q.93 i); messages which are too short to contain a complete message type (see 0 5.8.2 of Recommendation Q.93 i); general information element errors (see 0 5.8.5 of Recommendation Q.93 1); mandatory information element
43、errors (see 0 5.8.6 of Recommendation Q.931). - - - On occurrence of these incorrect messages a counter will be incremented. If the counter exceeds a certain threshold, the OS shall be notified. The OS may initiate a procedure to disconnect the connection with the subscriber installation or send a m
44、essage to the user. The reception of this frame indicates that the exchange termination did not establish a link successfully. Recommendation M.3640 (lO92) 5 COPYRIGHT International Telecommunications Union/ITU TelecommunicationsLicensed by Information Handling Services4.2.2 Call reference errors In
45、 the protocol a call reference is used to specify a call. If in a message the call reference value is not correct (see Table l/M.3640), than a counter shall be raised or this message shall be logged. If the messages are being counted, the OS shall be informed after a threshold is crossed. Messages A
46、ll messages except: SETUP, STATUS, RESUME SET-UP, RESUME SET-UP All messages except: RESTART, RESTART ACK, STATUS Call reference value which is not relating to an active call or a call in progress which is not relating to an active call or a call in progress and with a call reference flag set to “1“
47、 which is relating to an active call or a call in progress which is the global call reference 4.2.3 Layer 3 performance monitoring and signalling abnormalities For the purpose of performance management and detection of signalling abnormalities the following message - STATUS messages received; - REST
48、ART messages received; - STATUS messages transmitted; - RESTART messages transmitted. types will be counted per D-channel or logged: The following messages will be logged: - DISCONNECT, RELEASE and RELEASE COMPLETE messages received, with a cause value other than normal event; DISCONNECT, RELEASE an
49、d RELEASE COMPLETE messages transmitted, with a cause value other than normal event. - 4.2.4 Expiry of system timers Upon expiry of the following system timers, the OS should be informed by means of a notification: - T308: - T309: The data link failure has not been recovered; - T3 16: - T3 17: The following expiries of protocol timers will be counted. After exceeding the threshold associated with this - T303: After the second expiry (which implies that the user did not respond) management could be informed, because it indicates a faulty situation: After reception of ca
