1、INTERNATIONAL TELECOMMUNICATION UNIONITU-T G.705TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU(10/2000)SERIES G: TRANSMISSION SYSTEMS AND MEDIA,DIGITAL SYSTEMS AND NETWORKSDigital transmission systems Terminal equipments GeneralCharacteristics of Plesiochronous DigitalHierarchy (PDH) equipment functi
2、onal blocksCAUTION !PREPUBLISHED RECOMMENDATIONThis prepublication is an unedited version of a recently approved Recommendation.It will be replaced by the published version after editing. Therefore, there will bedifferences between this prepublication and the published versionFOREWORDThe Internation
3、al Telecommunication Union (ITU) is the United Nations specialized agency in the field oftelecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ ofITU. ITU-T is responsible for studying technical, operating and tariff questions and issuingRecommendations on
4、them with a view to standardizing telecommunications on a worldwide basis.The World Telecommunication Standardization Assembly (WTSA), which meets every four years,establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations onthese topics.The approval of ITU-T
5、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 areprepared on a collaborative basis with ISO and IEC.NOTEIn this Recommendation, the expression “Administration“ is used for c
6、onciseness to indicate both atelecommunication administration and a recognized operating agency.INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation mayinvolve the use of a claimed Intellectual Property Right. ITU takes no posi
7、tion concerning the evidence,validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or othersoutside of the Recommendation development process.As of the date of approval of this Recommendation, ITU had/had not received notice of intellectualproperty, prote
8、cted 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 stronglyurged to consult the TSB patent database. ITU 2000All rights reserved. No part of this publication may be reproduce
9、d or utilized in any form or by any means,electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU.Recommendation G.705 (10/2000) Prepublished version 1RECOMMENDATION G.705CHARACTERISTICS OF PLESIOCHRONOUS DIGITAL HIERARCHY (PDH)EQUIPMENT FUNCTIONAL BLOC
10、KS(Montreal, 2000)SummaryThis Recommendation specifies both the components and the methodology that should be used inorder to specify PDH functionality of network elements; it does not specify an individual PDHequipment as such.KeywordsPDH, equipment functional blocks1ScopeThis Recommendation covers
11、 the functional requirements of PDH functionality within equipment.Some examples are: PDH interfaces on ATM equipment PDH interfaces on SDH equipment PDH interfaces on PDH multiplexer.G.705 encompasses all the requirements of G.704, G.742, G.743, G.747, G.751 and G.752. Assuch, all equipment designe
12、d to these Recommendations is by definition compliant with G.705.When any discrepancy exists, the requirements of these Recommendations supersede for existingdesigns.NOTE - Appendix I provides for information the equivalent representations of PDH multiplexerequipment using atomic functions described
13、 in this Recommendation. It underlines the resultingdifferences compared to the specification given in G.742 and G.751.This Recommendation uses the same specification methodology as the one used in ITU-TRecommendation G.806. The description is generic and no particular physical partitioning offuncti
14、ons is implied. The input/output information flows associated with the functional blocks servefor defining the functions of the blocks and are considered to be conceptual, not physical.Not every atomic functions defined in this Recommendation is required for every application.Different subsets of at
15、omic functions from this Recommendation and others (e.g. G.783) may beassembled in different ways according to the combination rules given in these Recommendations toprovide a variety of different capabilities. Network operators and equipment suppliers may choosewhich functions must be implemented f
16、or each application.The internal structure of the implementation of this functionality (equipment design) need not beidentical to the structure of the functional model, as long as all the details of the externallyobservable behaviour comply with the EFS.Recommendation G.705 (10/2000) Prepublished ve
17、rsion 22 ReferencesThe following Recommendations and other references contain provisions which, through referencein this text, constitute provisions of this Recommendation. At the time of publication, the editionsindicated were valid. All Recommendations and other references are subject to revision;
18、 all users ofthis Recommendation are therefore encouraged to investigate the possibility of applying the mostrecent edition of the Recommendations and other references listed below. A list of the currentlyvalid ITU-T Recommendations is regularly published.1 ITU-T Recommendation E.862 (1992), Dependa
19、bility planning of telecommunicationnetworks.2 ITU-T Recommendation G.703 (1998), Physical electrical characteristics of hierarchicaldigital interfaces.3 ITU-T Recommendation G.704 (1998), Synchronous frame structures used at 1544, 6312,2048, 8488 and 44 736 kbit/s hierarchical levels.4 ITU-T Recomm
20、endation G.706 (1991), Frame alignment and cyclic redundancy check(CRC) procedures relating to basic frame structures defined in Recommendation G.704.5 ITU-T Recommendation G.743 (1988), Second order digital multiplex equipment operatingat 6312 kbit/s and using positive justification.6 ITU-T Recomme
21、ndation G.752 (1980), Characteristics of digital multiplex equipmentsbased on a second order bit rate of 6312 kbit/s and using positive justification.7 ITU-T Recommendation G.775 (1998), Loss of signal (LOS), Alarm Indication Signal (AIS)and Remote Defect Indication (RDI) and clearance criteria.8 IT
22、U-T Recommendation G.781 (1999), Synchronization layer functions.9 ITU-T Recommendation G.783 (2000), Characteristics of synchronous digital hierarchy(SDH) equipment functional blocks.10 ITU-T Recommendation G.805 (1995), Generic functional architecture of transportnetworks.11 ITU-T Recommendation G
23、.806 (2000), Characteristics of Transport Equipment Description Methodology and Generic Functionality.12 ITU-T Recommendation G.810 (1996), Definitions and terminology for synchronizationnetworks.13 ITU-T Recommendation G.812 (1998), Timing requirements of slave clocks suitable foruse as node clocks
24、 in synchronization networks.14 ITU-T Recommendation G.823, The control of jitter and wander within digital networkswhich are based on the 2048 kbit/s hierarchy.15 ITU-T Recommendation G.824, The control of jitter and wander within digital networkswhich are based on the 1544 kbit/s hierarchy.16 ITU-
25、T Recommendation G.826 (1999), Error performance parameters and objectives forinternational, constant bit rate digital paths at or above the primary rate.17 ITU-T Recommendation M.3010 (1996), Principles for a telecommunications managementnetwork.18 ITU-T Recommendation G.742 (1988), Second order di
26、gital multiplex equipment operatingat 8448 kbit/s and using positive justificationRecommendation G.705 (10/2000) Prepublished version 319 ITU-T Recommendation G.751 (1988), Digital multiplex equipments operating at the thirdorder bit rate of 34 368 kbit/s and the fourth order bit rate of 139 264 kbi
27、t/s and usingpositive justification3 Terms and DefinitionsAccess Point (AP) - See Recommendation G.805 10.Access Point Identifier (APId) - See Recommendation G.831.Adaptation function (A) - See Recommendation G.805.Adapted Information (AI) See Recommendation G.806 11.Administrative Unit (AU) - See R
28、ecommendation G.707.Administrative Unit Group (AUG) - See Recommendation G.707.Alarm - See Recommendation G.806.All-ONEs See Recommendation G.806.Anomaly - See Recommendation G.806.Atomic function See Recommendation G.806.AUn-AIS - See Recommendation G.707.Bidirectional trail/connection type See Rec
29、ommendation G.806.Bit Interleaved Parity (BIP) - See Recommendation G.707.Broadcast connection type See Recommendation G.806.Characteristic Information (CI) See Recommendation G.806.Client/server layer See Recommendation G.806.Connection - See Recommendation G.805.Connection function (C) See Recomme
30、ndation G.806.Connection Matrix (CM) See Recommendation G.806.Connection Point (CP) See Recommendation G.806.Consolidation - See Recommendation G.806.Common Management Information Service Element (CMISE) - See Recommendation X.710and ISO/IEC 9595.Compound function - See Recommendation G.806.Data Com
31、munications Channel (DCC) - See Recommendation G.784.Defect - See Recommendation G.806.Failure - See Recommendation G.806.Fault - See Recommendation G.806.Fault cause See Recommendation G.806.Function - See Recommendation G.806.Grooming - See Recommendation G.806.Layer See Recommendation G.806.Manag
32、ement Information (MI) - See Recommendation G.806.Management Point (MP) - See Recommendation G.806.Network Connection (NC) - See Recommendation G.805.Recommendation G.705 (10/2000) Prepublished version 4Network Element Function (NEF) - See Recommendation G.784.Path See Recommendation G.806.Pointer J
33、ustification Event (PJE) See Recommendation G.783 9.Process - See Recommendation G.806.Reference point - See Recommendation G.806.Remote Defect Indication (RDI) - See Recommendation G.806.Remote Error Indication (REI) - See Recommendation G.806.Remote Information (RI) - See Recommendation G.806.Remo
34、te Point (RP) See Recommendation G.806.Server Signal Degrade (SSD) - See Recommendation G.806.Server Signal Fail (SSF) - See Recommendation G.806.Signal Degrade (SD) - See Recommendation G.806.Signal Fail (SF) - See Recommendation G.806.Sub-Network Connection (SNC) - See Recommendation G.805.Telecom
35、munications Management Network (TMN) - See Recommendation M.3010.Termination Connection Point (TCP) - See Recommendation G.806.Timing Information (TI) - See Recommendation G.806.Timing Point (TP) - See Recommendation G.806.Trail - See Recommendation G.805.Trail Signal Degrade (TSD) - See Recommendat
36、ion G.806.Trail Signal Fail (TSF) - See Recommendation G.806.Trail termination function (TT) - See Recommendation G.806.Trail Trace Identifier (TTI) - See Recommendation G.707.NE Transit Delay - See Recommendation G.806.Tributary Unit (TU-m) - See Recommendation G.707.TUm-AIS - See Recommendation G.
37、707.Virtual Container (VC-n) - See Recommendation G.707.Undefined bit - See Recommendation G.806.Undefined byte - See Recommendation G.806.4 AbbreviationsFor the purpose of this Recommendation, the following abbreviations are used:A Adaptation functionAcSL Accepted Signal LabelAcTI Accepted Trace Id
38、entifierADM Add-Drop MultiplexerAI Adapted InformationAIS Alarm Indication SignalAP Access PointRecommendation G.705 (10/2000) Prepublished version 5APId Access Point IdentifierATM Asynchronous Transfer ModeAU Administrative UnitAU-n Administrative Unit, level nAUG Administrative Unit GroupBER Bit E
39、rror RatioBBER Background Block Error RatioBIP Bit Interleaved ParityC Connection functionCI Characteristic InformationCK ClockCM Connection MatrixCMISE Common Management Information Service ElementCP Connection PointCRC Cyclic Redundancy CheckCRC-N Cyclic Redundancy Check, width NCSES Consecutive S
40、everely Errored SecondsDDatDCC Data Communications ChannelDS Defect SecondDEC DecrementDEG DegradedDEGTHR Degraded ThresholdDXC Digital Cross ConnectE0 Electrical interface signal 64 kbit/sE11 Electrical interface signal 1 544 kbit/sE12 Electrical interface signal 2 048 kbit/sE22 Electrical interfac
41、e signal 8 448 kbit/sE31 Electrical interface signal 34 368 kbit/sE32 Electrical interface signal 44 736 kbit/sE4 Electrical interface signal 139 264 kbit/sEBC Errored Block CountEDC Error Detection CodeEDCV Error Detection Code ViolationEMF Equipment Management FunctionEQ EquipmentES Electrical Sec
42、tionES1 Electrical Section, level 1ES Errored SecondRecommendation G.705 (10/2000) Prepublished version 6Eq Recommendation G.703 2 type electrical signal, bit rate order q (q=11, 12, 21, 22,31, 32, 4)ExSL Expected Signal LabelExTI Expected Trace IdentifierF_B Far-end BlockF_DS Far-end Defect SecondF
43、_EBC Far-end Errored Block CountFAS Frame Alignment SignalFIFO First In First OutFM Fault ManagementFOP Failure Of ProtocolFS Forced SwitchFS Frame Start signalHO Higher OrderHOA Higher Order AssemblerHOI Higher Order InterfaceHOVC Higher Order Virtual ContainerHP Higher order PathHPA Higher order P
44、ath AdaptationHPC Higher order Path ConnectionHPOM Higher order Path Overhead MonitorHPP Higher order Path ProtectionHPT Higher order Path TerminationHPP Higher order Path ProtectionHSUT Higher order path Supervisory Unequipped TerminationHTCA Higher order path Tandem Connection AdaptationHTCT Highe
45、r order path Tandem Connection TerminationHTCM Higher order path Tandem Connection MonitorHUG Higher order path Unequipped GeneratorID IdentifierIEC Incoming Error CountIF In Frame stateINC IncrementIncAIS Incoming AISLC Link ConnectionLO LockoutLO Lower OrderLOA Loss Of Alignment; generic for LOF,
46、LOM, LOPLOF Loss Of FrameRecommendation G.705 (10/2000) Prepublished version 7LOI Lower Order InterfaceLOM Loss Of MultiframeLOP Loss Of PointerLOS Loss of SignalLOVC Lower Order Virtual ContainerLP Lower order PathLPA Lower order Path AdaptationLPC Lower order Path ConnectionLPOM Lower order Path O
47、verhead MonitorLPP Lower order Path ProtectionLPT Lower order Path TerminationLTC Loss of Tandem ConnectionLTCA Lower order path Tandem Connection AdaptationLTCT Lower order path Tandem Connection TerminationLTCM Lower order path Tandem Connection MonitorLTI Loss of all Incoming Timing referencesLUG
48、 Lower order path Unequipped GeneratorMC Matrix ConnectionMCF Message Communications FunctionMI Management InformationMON MonitoredMP Management PointMRTIE Maximum Relative Time Interval ErrorMS Manual SwitchMSB Most Significant BitMTIE Maximum Time Interval ErrorN_B Near-end BlockN_BBE Near-end Bac
49、kground Block ErrorN_DS Near-end Defect SecondN_EBC Near-end Errored Block CountNC Network ConnectionN.C. Not ConnectedNDF New Data FlagNE Network ElementNEF Network Element FunctionNNI Network Node InterfaceNMON Not MonitoredNU National UseOAM Operation, Administration and MaintenanceRecommendation G.705 (10/2000) Prepublished version 8ODI Outgoing Defect IndicationOEI Outgoing Error IndicationOF_B Outgoing Far-end BlockOF_BBE Outgoing Far-end Background Block ErrorOF_DS Outgoing Far-end Def
