1、- - ITU-T RECMNxQ.2144 75 4862591 0616677 952 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU B-ISDN ATM ADAPTATION LAYER (2.21 44 (1 0195) B-ISDN SIGNALLING ATM ADAPTATION LAYER (SAAL) - LAYER MANAGEMENT FOR THE SAAL AT THE NETWORK NODE INTERFACE (NNI) IT
2、U-T Recommendation Q.2144 (Previously “CCITT Recommendation”) FOREWORD The -T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations
3、 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 topics for study by the -T Study Groups which, in their turn, produce Recommendations on these topics. The appro
4、val of Recommendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation 4.2144 was prepared by ITU-T Study Group 11 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 17th of Octobe
5、r 1995. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1996 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, e
6、lectronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*6?=2L44 95 4Bb259L DbLbb79 725 m CONTENTS Scope References 2.1 Normative references 2.2 Informative references Abbreviations and acronyms Model for interactions with Layer Managemen
7、t Interface Between Layer Management and the SAAL at the “I . 5.1 Interface Between Layer Management and SSCOP . 5.2 Interface Between Layer Management and the SSCF at the “I State Transition Table of LM for the management of SAAL at “I . Interface to systems management . Peer-to-peer Layer Manageme
8、nt communication Procedures of Layer Management 9.1 Error processing 9.2 Measurements . 9.3 Handling of processor outage conditions 9.4 Management of signalling link proving Annex A . Real system resources . Appendix I . Management error indications . Appendix II . Example of error monitoring of In-
9、Service links . iI.1 Overview II.2 Detailed description II.3 Rationale for default parameters . II.4 Proving Recommendation Q.2144 (10/95) Page 1 1 1 1 2 3 3 3 5 7 12 12 12 12 14 16 16 17 18 19 19 19 22 23 1 ITU-T RECMN*0-2144 95 = 4862591 Ob16680 447 SUMMARY The ATM Adaptation Layer (AAL) is define
10、d to enhance the services provided by the ATM layer to support the functions required by the next higher layer. One particular type of AAL service is the Signalling AAL (SAAL) which comprises AAL functions necessary to support a signalling entity. The structure of the SAAL is defined in Recommendati
11、on Q.2100. The SAAL, consists of a Segmentation And Reassembly (SAR) function, and a Convergence Sublayer which is divided into two sublayers: a Common Part Convergence Sublayer (CPCS) and a Service Specific Convergence Sublayer (SSCS). The common part protocol is defined in clause 6h.363, and is us
12、ed as the underlying protocol for the service specific part for signalling. The SSCS is functionally divided into two parts. The Service Specific Connection Oriented Protocol (SSCOP), which provides an assured data transfer service and the Service Specific Coordination Function (SSCF). The SSCOP is
13、defined in Recommendation 4.2110 and is suitable for use by various SSCFs. This Recommendation specifies the layer management functions for the SAAL at the Network Node Interface (“I). The layer management functions at the “I perform error monitoring and a coordination function between the systems m
14、anagement function and the SAAL. This Recommendation describes the NNI layer management functions associated with the management primitives between the SAAL sublayers and the layer management entity. KEYWORDS Error monitoring, Layer management, “i, SAAL ii Recommendation Q.2144 (10195) Recommendatio
15、n Q.2144 B-ISDN SIGNALLING ATM ADAPTATION LAYER (SAAL) - LAYER MANAGEMENT FOR THE SAAL AT THE NETWORK NODE INTERFACE (NNI) (Geneva, 1995) 1 Scope This Recommendation specifies the Layer Management functions for the Signalling ATM Adaptation Layer (SAAL) at the Network Node Interface (“X). These incl
16、ude the interfaces to the Service Specific Connection Oriented Protocol (SSCOP, Recommendation Q.2110 2), to the Service Specific Coordination Function (SSCF) at the “i (Recommendation 4.2140 3), and to systems management. Layer Management provides, or supports, the following functions for the Servi
17、ce Specific Convergence Sublayer (SSCS) at the “I: error processing; 0 measurements; 0 notification of processor outage status; 0 determination of link quality during proving; and 0 determination of link quality during normal operation. 2 References The following Recommendations and other references
18、 contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision: all users of this Recommendation are therefore encouraged to inves
19、tigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid JTU-T Recommendations is regularly published. Normative references ITU-T Recommendation 1.363 (1993), B-ISDN ATM Adaptation Layer (AAL) specification. IT
20、U-T Recommendation Q.2110 (1994), B-ISDN ATM adaptation layer - Service Specific Connection Oriented Protocol (SSCOP). ITU-T Recommendation 4.2140 (1993, B-ISDN ATM adaptation layer - Service Specific Coordination Function for signalling at the Network Node Integace (SSCF AT “1). Informative referen
21、ces ITU-T Recommendation 4.703 (1993), Signalling System No. 7 Signalling link. ITU-T Recommendation 4.704 (1993), Signalling System No. 7 Signalling network functions and messages. ITU-T Recommendation 4.750 (1993). Overview of Signalling System No. 7 management. ITU-T Recommendation 4.752 (1993),
22、Monitoring and measurements for Signalling System No. 7 networks. Recommendation Q.2144 (10/95) 1 ITU-T RECMN*Q=2144 75 4862591i 0616682 2LT W 3 Abbreviations and acronyms For the purposes of this Recommendation, the following abbreviation are used. AA ATM Adaptation AAL ATM Adaptation Layer ALN Ali
23、gnment ANS Alignment Not Successful ATM Asynchronous Transfer Mode BER Bit Error Ratio BGAK Begin Acknowledge (SSCOP PDU) BGN Begin (SSCOP PDU) BGEJ Begin Reject (SSCOP PDU) B-ISDN cc Congestion Ceased CD Congestion Detected END End (SSCOP PDU) ENDAK End Acknowledge (SSCOP PDU) ER Error Recovery (SS
24、COP PDU) ERAK INS IN Service LM Layer Management LPO Local Processor Outage LR Local Release MAA Management ATM Adaptation MAAL Management ATM Adaptation Layer MD Management Data (SSCOP PDU) MPS Management Proving State MTP Message Transfer Part MTP-2 MTP-3 Mu Message Unit NC NO CREDIT “I Network No
25、de Interface NRP 00s Out Of Service os1 Open Systems Interconnection PDU Protocol Data Unit PDUT SSCOP PDU Transmitted Broadband Integrated Services Digital Network Error Recovery Acknowledge (SSCOP PDU) Message Transfer Part Level 2 Message Transfer Part Level 3 Number of Retransmitted SSCOP PDUs 2
26、 Recommendation 0.2144 (10/95) - ITU-T RECflN*C-ZLLIY 95 4862593 0636683 356 PE PNS PO POLL QOS RR RS RSAK RSREC SAAL SAR SD SR SREC SSCF SSCOP SSCOP-uu sscs STAT UD UDR USTAT Protocol Error Proving Not Successful Processor Outage Poll (SSCOP PDU) Quality of Service Remote Release Resynchronization
27、(SSCOP PDU) Resynchronization Acknowledge (SSCOP PDU) Timer-REPEAT-SREC Signalling ATM Adaptation Layer Segmentation And Reassembly Sequenced Data (SSCOP PDU) SSCOP Release SSCOP RECover Service Specific Coordination Function Service Specific Connection Oriented Protocol SSCOP User-to-User Informati
28、on Service Specific Convergence Sublayer Solicited STATUS (SSCOP PDU) Unnumbered Data (SSCOP PDU) UNITDATA Received Unsolicited STATUS (SSCOP PDU) 4 Figure 1 shows the relationship of Layer Management to other protocols and management entities. In the figure, solid lines connect Layer Management to
29、entities with which it interacts directly. Sections 5, 6 and 7 provide more information on these interfaces. Model for interactions with Layer Management 5 This clause defines the signals between the Layer Management entity for the SAAL at the “I and between the SSCF at the “I and the SSCOP. Subclau
30、se 5.1 defines the interface to SSCOP. Subclause 5.2 defines the interface to the SSCF at the “i. For information concerning the interface of AAL Type 5 Common Part to Layer Management, consult 6A.363 i. NOTE - Currently there are no interactions between the AAL Type 5 Common Part and Layer Manageme
31、nt specified in Recommendation 1.363 I. Interface Between Layer Management and the SAAL at the “I 5.1 Between Layer Management and the SSCOP the signals contained in Table 1 are defined: Interface Between Layer Management and SSCOP Recommendation Q.2144 (10/95) 3 - ITU-T RECMN*Q-2144 7.5 Y8b259L Ob3
32、6684 O92 - SSCF at NNI L - I - SSCOP - AAL Type 5 Common Pari FIGURE UQ.2144 Generic name Relationships of Layer Management with other entities MAA-ERROR MAA-UNITDATA TABLE UQ.2144 Signais and Parameters between SSCOP and Layer Management Not Defined Code, Count Not Defined Not Defined MU MU Not Def
33、ined Not Defined The definitions of these signais are found in Recommendation 4.21 10 2. They are shown here for ease of reference. The MAA-ERROR signai is used by SSCOP to report the occurrence of various error events to Layer Management. The MAA-UNITDATA signais are used for the non-assured transf
34、er of information between peer Layer Management entities. NOTE - Thus far, no procedures using the MAA-UNITDATA signai have been defined for the Layer Management for the SAAL at the NNI. 4 Recommendation Q.2144 (10/95) ITU-T RECMN*Q=2144 75 4862573 0636685 T27 MAAL-PROVING.indication MAAL-CLEAR-FORC
35、E-MODES.request The parameters in these signals are defined as follows: o The Message Unit (MU) parameter contains the service data unit that is transferred from Layer Management to SSCOP in the MAA-UNITDATA.request and from SSCOP to Layer Management in the The Code parameter indicates the type of e
36、rror that occurred. A table of errors that can be reported and the corresponding Code values are given in Recommendation Q.2110 2 and are replicated for convenience in Appendix I. The Count parameter indicates the number of SD PDU retransmissions that occurred. . MAA-UNITDATAhdication. o o SSCF to L
37、M LM to SSCF 5.2 Between Layer Management and the “I SSCF the signals contained in Table 2 are defined in Recommendation Q.2140 3. These definitions are repeated below for the convenience of the reader. Interface Between Layer Management and the SSCF at the NNI MAAL-FORCE-PROVING.request MAAL-STOP-P
38、ROVING.indication TABLE 2/4.2144 Signals between SSCF at the NM and Layer Management LM to SSCF SSCF to LM I Signais I Direction I MAAL-PROVING-UNSUCCESSFiJL.response M AAL-RELEASE.request MAAL-LOCAL-PROCESSOR_OUTAGE.request LM to SSCF LM to SSCF LM to SSCF I MAAL-FORCEFMERGENCY .request MAAL-LOCAL-
39、PROCESSOR-RECOVERED.request MAAL-REPORT.indication I LM to SSCF I LM to SSCF SSCF to LM These signals are defined as follows: “MAAL-PROViNGhdication“ is used by SSCF to initiate the error monitoring within Layer Management for connection proving. “MAAL-FORCE-PROVING.request“ is used to instruct SSCF
40、 to implement forced proving. “MAAL-FORCE-EMERGENCY .request“ is used to instruct SSCF to omit proving. “MAAL-CLEAR-FORCE-MODES .request“ is used to notify SSCF that Layer Management is indifferent to which proving mode is used. “MAAL-RELEASE.request“ is used to instruct SSCF to release the connecti
41、on. “MAAL-STOPPROVINGhdication“ is used to indicate that the proving procedure has terminated. Recommendation Q.2144 (10/95) 5 - ITU-T RECMN*Q.2144 95 m 4862591 ObLbbb 965 ”MAAL-PROVING-UNSUCCESSFUL.response“ is used to notify SSCF that the proving was not successful. “MAAL-LOCAL-PROGESSOR0UTAGE.req
42、uest” is used to notify SSCF of local processor outage. “MAAL-LOCAL-PROCESSOR-RECOVERED.request” is used to notify SSCF that the local processor has recovered. “MAAL-REPORThdication” is used to notify Layer Management of events detected by SSCF. The generic structure for the MAAL-REPORT.indication i
43、s: MAAL-REPORT.indication (“lower boundary conditions,” “upper boundary conditions,” “reasons in case of exceptional situations”) The “lower boundary conditions” parameter reports whether the SSCOP connection was released by the remote or local SSCF or by SSCOP itself if the event being reported inv
44、olves release of the SSCOP connection; it can take values RR, LR, SR, or -. The “upper boundary conditions” parameter reports the interface state at the upper boundary of the SSCF into which a transition was made if the event being reported involves a transition at this boundary; it can take values
45、OOS, INS, ALN, or -. The “reasons in case of exceptional situations” parameter reports the reason for transitions reported in the lower boundary conditions or upper boundary conditions parameters or the type of event being reported when the boundary conditions parameters are empty; it can take value
46、s ANS, SREC, SSCOP-W, PE, CD, CC, PDUT, UDR, or -. Key ALN ANS cc CD INS LR 00s PDUT PE RR SR SREC SSCOP-uu UDR Alignment Alignment Not Successful Congestion Ceased Congestion Detected IN Service Local Release Out Of Service SSCOP PDU Transmitted Protocol Error Remote Release SSCOP Release SSCOP REC
47、over SSCOP User-to-User Information UNITDATA Received empty These parameter values of the MAAL-REPORT.indication and other MAAL-signals provide the Layer Management with an unambiguous view of the status of SSCF (see Table 614.2140 3 for applicability of notifications). In the state transition diagr
48、am Figure 2: a) b) the signal MAAL-REPORT.indication (-,-,UDR) is possible in any state. This is not shown; any other signal which is not shown as resulting in a transition (from one state to the same state, or from one state to a different state) is not permitted in that state; 6 Recommendation Q.2
49、144 (10195) ITU-T RECMN*Q*ZL44 75 qBb2571 Ub1bbd7 8TL c) it is assumed that the signals passed between LM and an SSCF are coordinated so that collisions do not occur; d) the following abbreviations are used: MAAL-PROVING-UNS = MAAL-PROVING-UNSUCCESSFUL, MAAL-LOCPROC-OUT = MAAL-LOCAL-PROCESSOR-OUTAGE, MAAL-LOC-PROC-REC = MAAL-LOCAL-PROCESSOR-RECOVERED. 6 State Transition Table of LM for the management of SAAL at “I This clause contains the state transition table, Table 3, of the LM for the management of SAAL at “i in support of an SAAL service wh
