1、INTERNATIONAL TELECOMMUNICATION UNIONITU-TM.2201TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU(03/2001)SERIES M: TMN AND NETWORK MAINTENANCE:INTERNATIONAL TRANSMISSION SYSTEMS,TELEPHONE CIRCUITS, TELEGRAPHY, FACSIMILEAND LEASED CIRCUITSInternational transport networkPerformance objectives, allocation
2、s and limitsfor bringing-into-service and maintenance of in-ternational atm virtual path and virtual channelconnectionsCAUTION !PREPUBLISHED RECOMMENDATIONThis prepublication is an unedited version of a recently approved Recommendation.It will be replaced by the published version after editing. Ther
3、efore, there will be dif-ferences between this prepublication and the published version.FOREWORDThe International Telecommunication Union (ITU) is the United Nations specialized agency in the field oftelecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of
4、ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommenda-tions on them with a view to standardizing telecommunications on a worldwide basis.The World Telecommunication Standardization Assembly (WTSA), which meets every four years, estab-lishes the topic
5、s for study by the ITU-T study groups which, in turn, produce Recommendations on thesetopics.The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.In some areas of information technology which fall within ITU-Ts purview, the necessary standards are pre-pare
6、 on a collaborative basis with ISO and IEC.NOTEIn this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecom-munication administration and a recognized operating agency.INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice o
7、r implementation of this Recommendation may in-volve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, valid-ity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others out-side of the Recommendation developme
8、nt process.As of the date of approval of this Recommendation, ITU had/had not received notice of intellectual prop-erty, protected by patents, which may be required to implement this Recommendation. However, implemen-tors are cautioned that this may not represent the latest information and are there
9、fore strongly urged to con-sult the TSB patent database. ITU 2001All 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 ITU.ITU-T M.2201 (03/2001) Pr
10、epublished version 1RECOMMENDATION M.2201PERFORMANCE OBJECTIVES, ALLOCATIONS AND LIMITS FOR BRINGING-INTO-SERVICE AND MAINTENANCE OF INTERNATIONAL ATM VIRTUAL PATHAND VIRTUAL CHANNEL CONNECTIONSSummaryThis Recommendation provides performance objectives, allocations and limits, and measure-ment proce
11、dures for bringing-into-service and maintenance of international end-to-end perma-nent and semi-permanent ATM Virtual Path Connections (VPCs), Virtual Channel Connections(VCCs), and connection portions that form part of an international ATM VPC or VCC. Error,delay and availability performance aspect
12、s are addressed. Some of the performance objectivesdepend on the users selection of Quality of Service (QoS) class, definitions of which are givenin Recommendations I.356 and I.371.IntroductionThis Recommendation describes the operational procedures and performance of ATM VPCs thatare designed and e
13、ngineered according to the relevant I-series Recommendations, and are used tosupport ATM VCCs. It relies heavily on the use of in-service monitoring facilities built intoATM equipment, and focuses on the F4 and F5 Operations, Administration and Maintenance(OAM) information flows specified in Recomme
14、ndation I.610. However, these OAM facilitiesare not present in all types of ATM equipment. Therefore, Out-Of-Service (OOS) tests will alsobe required to ensure operational performance limits are met during Bringing-Into-Service (BIS)and maintenance activities.The long-term (one month) cell transfer
15、and availability performance objectives for ATM net-works are defined in Recommendations I.356 and I.357 respectively. Short-term cell transfer andavailability performance requirements from an operation and maintenance perspective are cov-ered in this Recommendation.I.356 and M.2201 apply end-to-end
16、 from terminal measuring point MPT to MPT. This Recom-mendation enables the derivation of the performance objectives for real connections according toITU-T Recommendation I.356 (which has a country-based model); the performance allocation toa single operator is not specifically addressed. In cases w
17、here multiple operators operate one ormore connections/portions, the subdivision of the objectives between them is subject to furtherstudy.This Recommendation is part of the M.22xx-series that address the operation and maintenanceof the ATM layer (i.e. above the physical layer). It does not address
18、the ATM Adaptation Layer(AAL) services or consider provisioning and commissioning of ATM equipment into the net-work. Recommendations in the M.21xx series provide performance objectives, allocations andlimits for the physical layer network supporting the ATM layer. The built-in monitoring used bythe
19、se Recommendations is the OAM information flows defined in I.610 as F1, F2 and F3.KeywordsAvailabilityBringing-Into-ServiceDegraded Performance LimitErrored SecondIn-Service MonitoringPerformance AllocationPerformance LimitsSeverely Errored SecondUnacceptable Performance LimitITU-T M.2201 (03/2001)
20、Prepublished version 2_List of Contents1 Scope 32 References 33 Terms and definitions 44 Abbreviations. 65 Hypothetical reference model 95.1 General model 95.1.1 Country-based model . 95.1.2 Operator-based model 105.2 Relationship of ATM virtual paths to physical paths 115.3 Testing arrangement. 116
21、 Performance objectives 126.1 Reference performance events, performance parameters and performance objectives . 126.2 Allocation principles for end-to-end VPCs/VCCs. 137 Performance measurements . 167.1 BIS performance measurements 167.2 Maintenance performance measurements 177.3 Availability 187.4
22、Evaluation of performance objectives . 188 Role within the TMN. 189 Performance limits. 189.1 Relationship between performance limits and objectives 189.2 Types of limits . 189.3 Process for calculation of ATM connection performance objectives and limits . 189.4 Long-term quality monitoring/measurem
23、ent . 18ITU-T M.2201 (03/2001) Prepublished version3RECOMMENDATION M.2201PERFORMANCE OBJECTIVES, ALLOCATIONS AND LIMITS FOR BRINGING-INTO-SERVICE AND MAINTENANCE OF INTERNATIONAL ATM VIRTUAL PATHAND VIRTUAL CHANNEL CONNECTIONS1ScopeThis Recommendation provides performance objectives, allocations and
24、 limits, and measure-ment procedures for bringing-into-service and maintenance of international, permanent or semi-permanent end-to-end ATM Virtual Path Connections (VPCs), Virtual Channel Connections(VCCs), and connection portions that form part of an international ATM VPC or VCC. Error,delay and a
25、vailability performance aspects are addressed.This Recommendation provides performance objectives, allocations and limits for Bringing-Into-Service (BIS) and maintaining international ATM permanent and semi-permanent VPCsthat are transported over PDH, SDH or optical fibre networks, referring to the
26、Operations, Ad-ministration and Maintenance (OAM) information flows F1-F5 (see Figure 3/I.610 7). ThisRecommendation is part of the M.22xx-series, which address flows F4 and F5 (i.e. above thephysical level); the M.21xx-series address flows F1-F3. This Recommendation does not addressthe ATM Adaptati
27、on Layer (AAL) services or consider provisioning and commissioning ofATM equipment into the network.Because BIS and maintenance requirements differ according to cell priority level, different limitsare provided based on Cell Loss Priorities CLP=0, and CLP=0+1. Performance parameters andlimits are al
28、so given for triggering maintenance activity (e.g. fault localisation, repair etc.).Automatic re-routing of cells in the case of a fault is assumed in the determination of limits. Thelimits are designed to support the long-term performance objectives in Recommendation I.3564.This Recommendation assu
29、mes the ATM cell format and structure described in Recommenda-tion I.150 1 and the use of Recommendation I.610 7 B-ISDN OAM principles and functions.Methods of deriving performance information from OAM cells and other path information aregiven.This Recommendation enables the derivation of the perfor
30、mance objectives for real connectionsaccording to IU-T Recommendation I.356 4 (which has a country-based model); the perform-ance allocation to a single operator is not specifically addressed. In cases where multiple opera-tors operate one or more connections/portions, the subdivision of the objecti
31、ves between them issubject to further study.2 ReferencesThe following ITU-T Recommendations contain provisions which, through reference in this text,constitute provisions of this Recommendation. All Recommendations are subject to revision; allusers of this Recommendation are therefore encouraged to
32、investigate the possibility of applyingthe most recent edition of the Recommendations listed below. A list of the currently valid ITU-TRecommendations is published regularly.1 ITU-T Recommendation I.150, B-ISDN ATM functional characteristics2 ITU-T Recommendation I.326, Functional architecture of tr
33、ansport networks based onATMITU-T M.2201 (03/2001) Prepublished version43 ITU-T Recommendation I.353, Reference events for defining ISDN and B-ISDN per-formance parameters4 ITU-T Recommendation I.356, B-ISDN ATM layer cell transfer performance5 ITU-T Recommendation I.357, B-ISDN semi-permanent conne
34、ction availability6 ITU-T Recommendation I.371, Traffic control and congestion control in B-ISDN7 ITU-T Recommendation I.610, B-ISDN operation and maintenance principles and func-tions8 ITU-T Recommendation M.20, Maintenance philosophy for telecommunication networks9 ITU-T Recommendation M.34, Perfo
35、rmance monitoring on international transmissionsystems and equipment10 ITU-T Recommendation M.60, Maintenance terminology and definitions11 ITU-T Recommendation M.2100, Performance limits for bringing-into-service andmaintenance of international PDH paths, sections and transmission systems12 ITU-T R
36、ecommendation M.2101, Performance limits for bringing-into-service andmaintenance of international SDH paths and multiplex sections13 ITU-T Recommendation M.2140, Transport network event correlation14 ITU-T Recommendation M.3010, Principles for a Telecommunications ManagementNetwork15 ITU-T Recommen
37、dation M.3200, TMN management services and telecommunicationsmanaged areas: overview16 ITU-T Recommendation M.3207.1, TMN management service: maintenance aspects ofB-ISDN management17 ITU-T Recommendations M.3400, TMN management functions18 ITU-T Recommendation M.3600, Principles for the management
38、of ISDNs19 ITU-T Recommendation M.3610, Principles for applying the TMN concept to the man-agement of BISDN20 ITU-T Recommendation M.3611, Test management of the B-ISDN ATM layer using theTMN21 ITU-T Recommendation O.191, Equipment to assess ATM layer cell transfer perform-ance3 Terms and definition
39、sGeneral terms and definitions relating to this Recommendation are provided in Recommenda-tions I.326 2, I.353 3, I.356 4, I.357 5, I.371 6, I.610 7, M.20 8, M.34 9, M.60 10,M.2100 11 and M.2101 12. For the purpose of this Recommendation, the following defini-tions also apply:Allocated Performance O
40、bjective (APO): An APO is the PO for a real connection calculatedaccording to the allocation rules defined in this Recommendation.Bringing-Into-Service Performance Objective (BISPO): A BISPO is the PO for a real con-nection or connection portion calculated from its APO and used for BIS testing.ITU-T
41、 M.2201 (03/2001) Prepublished version5Connection Point (CP): A CP is a reference point where the output of a trail termination sourceor a connection is bound to the input of another connection, or where the output of a connectionis bound to the input of a trail termination sink or another connectio
42、n.End-to-end VPC or VCC: An end-to-end VPC or VCC is the VPC or VCC existing betweentwo MPTs and may traverse a number of ATM switching/cross-connect nodes.Measurement Point (MP): A MP is located at an interface that separates either CustomerEquipment (CEQ)/customer network or a Switching/Signalling
43、 Node (SSN) from an attachedtransmission system at which ITU-recommended protocols can be observed.Note 1 The term SSN collectively denotes any equipment that accesses the ATM layer inthe transport network under consideration.Note 2 As defined, MPs exist at many physical interfaces in a connection.
44、It is not theintention in this Recommendation to specify performance between arbitrary pairs of MPs.Note 3 For B-ISDN, the MPs are located at interfaces where the ATM is accessible. Theexact location within the protocol stack depends on whether the connection is a VPC or aVCC.Measurement Point O (MP
45、O): A MPO is located at an interface that terminates a transmissionsystem, for example, at an operators boundary (Point Of Presence (POP) or an InternationalSwitching Centre (ISC). MPTs and individual associated MPOs delimit portions of an end-to-end connection for which performance objectives are s
46、pecified.Measurement Point T (MPT): A MPT is located at an interface associated with a T referencepoint. This interface separates CEQ from an attached digital section. The T (or TBin the case ofB-ISDN) may be different from the ideal location and difficult to access. Two practical methodsfor measuri
47、ng at the B-ISDN MPT are:locating a physical test set at the MPT and replicating the ATM protocol functions outside of theCEQ, orapproximating the performance at the MPT by observations made within the network at the firstpoint where the ATM layer is observable.OAM Flow: Information flow transferred
48、 through the network by the means of a dedicatedchannel supported by specific bytes or bits of the transmission systems for the physical layer andby specific ATM cells referred to as OAM cells for the ATM layer.Performance Objective (PO): A PO is the target performance to be achieved over the end-to
49、-end reference connection specified in this Recommendation, (see Figure 1 for an example), as-suming a maximum length of 27,500 km.Permanent Virtual Path Connection (VPC) or Virtual Channel Connection (VCC): A per-manent VPC or VCC is the ATM layer connection which exists between two MPTs or two ATMswitches/cross-connect nodes that is permanently set up and configured for transporting ATMinformation between those two points. Each VPC is considered to be a unidir
