1、 International Telecommunication Union ITU-T G.780/Y.1351TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2008) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments Principal characteristics of multiplexing equipment for the synchronous digital hierar
2、chy SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Transport Terms and definitions for synchronous digital hierarchy (SDH) networks Recommendation ITU-T G.780/Y.1351 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND
3、 MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTER
4、ISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799
5、 General G.700G.709 Coding of analogue signals by pulse code modulation G.710G.719 Coding of analogue signals by methods other than PCM G.720G.729 Principal characteristics of primary multiplex equipment G.730G.739 Principal characteristics of second order multiplex equipment G.740G.749 Principal ch
6、aracteristics of higher order multiplex equipment G.750G.759 Principal characteristics of transcoder and digital multiplication equipment G.760G.769 Operations, administration and maintenance features of transmission equipment G.770G.779 Principal characteristics of multiplexing equipment for the sy
7、nchronous digital hierarchy G.780G.789 Other terminal equipment G.790G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSP
8、ORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.780/Y.1351 (03/2008) i Recommendation ITU-T G.780/Y.1351 Terms and definitions for synchronous digital hierarch
9、y (SDH) networks Summary Recommendation ITU-T G.780/Y.1351 provides terms, definitions, and abbreviations used in synchronous digital hierarchy (SDH) Recommendations. Physical layer terminology, synchronization-related terminology, and terms applicable to multiple technologies in addition to SDH are
10、 not included. The goal of this Recommendation is to be a single normative source for terms in this subject area. Source Recommendation ITU-T G.780/Y.1351 was approved on 29 March 2008 by ITU-T Study Group 15 (2005-2008) under Recommendation ITU-T A.8 procedure. Keywords Definitions, Synchronous Dig
11、ital Hierarchy (SDH), terminology. ii Rec. ITU-T G.780/Y.1351 (03/2008) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization S
12、ector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets ev
13、ery four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. 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 purvi
14、ew, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is volun
15、tary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the
16、negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve t
17、he use of a claimed Intellectual Property Right. 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 Recommend
18、ation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at htt
19、p:/www.itu.int/ITU-T/ipr/. ITU 2008 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.780/Y.1351 (03/2008) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.
20、2 Terms defined in this Recommendation. 3 4 Abbreviations and acronyms 14 Rec. ITU-T G.780/Y.1351 (03/2008) 1 Recommendation ITU-T G.780/Y.1351 Terms and definitions for synchronous digital hierarchy (SDH) networks 1 Scope This Recommendation contains a list of terms, definitions, and abbreviations
21、used in Recommendations dealing with synchronous digital hierarchy (SDH) networks. SDH terms specific to synchronization or physical layer or characteristics are not a part of this Recommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through
22、 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; users of this Recommendation are therefore encouraged to investigate the possibility of applying the
23、 most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.702 R
24、ecommendation ITU-T G.702 (1988), Digital hierarchy bit rates. ITU-T G.703 Recommendation ITU-T G.703 (2001), Physical/electrical characteristics of hierarchical digital interfaces. ITU-T G.707 Recommendation ITU-T G.707/Y.1322 (2007), Network node interface for the synchronous digital hierarchy (SD
25、H). ITU-T G.783 Recommendation ITU-T G.783 (2006), Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks. ITU-T G.784 Recommendation ITU-T G.784 (1999), Synchronous digital hierarchy (SDH) management. ITU-T G.803 Recommendation ITU-T G.803 (2000), Architecture of transpo
26、rt networks based on the synchronous digital hierarchy (SDH). ITU-T G.805 Recommendation ITU-T G.805 (2000), Generic functional architecture of transport networks. ITU-T G.806 Recommendation ITU-T G.806 (2006), Characteristics of transport equipment Description methodology and generic functionality.
27、 ITU-T G.826 Recommendation ITU-T G.826 (2002), End-to-end error performance parameters and objectives for international, constant bit-rate digital paths and connections. ITU-T G.828 Recommendation ITU-T G.828 (2000), Error performance parameters and objectives for international, constant bit-rate s
28、ynchronous digital paths. ITU-T G.829 Recommendation ITU-T G.829 (2002), Error performance events for SDH multiplex and regenerator sections. ITU-T G.841 Recommendation ITU-T G.841 (1998), Types and characteristics of SDH network protection architectures. ITU-T G.842 Recommendation ITU-T G.842 (1997
29、), Interworking of SDH network protection architectures. 2 Rec. ITU-T G.780/Y.1351 (03/2008) ITU-T G.870 Recommendation ITU-T G.870/Y.1352 (2008), Terms and definitions for optical transport networks (OTN). ITU-T G.7712 Recommendation ITU-T G.7712/Y.1703 (2008), Architecture and specification of dat
30、a communication network. ITU-T M.3010 Recommendation ITU-T M.3010 (2000), Principles for a telecommunications management network. ITU-T X.710 Recommendation ITU-T X.710 (1997) | ISO/IEC 9595:1998, Information technology Open Systems Interconnection Common Management Information service. 3 Definition
31、s 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 Terms defined in ITU-T G.805: access point (AP) adaptation characteristic information (CI) connection connection point (CP) network connection (NC) subnetwork connection (SNC) trail trail termination
32、function (TT) 3.1.2 Terms defined in ITU-T G.806: alarm all ONEs defect failure function management information (MI) path process signal degrade (SD) signal fail (SF) 3.1.3 Term defined in ITU-T G.7712: embedded control channel (ECC) 3.1.4 Terms defined in ITU-T G.870: bridge Rec. ITU-T G.780/Y.1351
33、 (03/2008) 3 head-end null signal switch tail-end 3.1.5 Term defined in ITU-T M.3010: telecommunications management network (TMN) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 active trail/path/section/SNC/NC: The trail/path/section/SNC from which th
34、e signal is selected by the protection selector. 3.2.2 adapted information (AI): The information passing across an AP. 3.2.3 add traffic: Normal or extra traffic inserted into working, protection, or non-pre-emptible unprotected channels on the ring at a ring node. 3.2.4 add/drop multiplexer (ADM):
35、Network element that provides access to all, or some subset of the constituent signals contained within an STM-N signal. The constituent signals are added to (inserted), and/or dropped from (extracted) the STM-N signal as it passes through the ADM. 3.2.5 administrative unit group (AUG): One or more
36、administrative units occupying fixed, defined positions in an STM payload are termed an administrative unit group (AUG). An AUG-1 consists of a homogeneous assembly of AU-3s or an AU-4. 3.2.6 administrative unit-n (AU-n): An administrative unit is the information structure which provides adaptation
37、between the higher order path layer and the multiplex section layer. It consists of an information payload (the higher order virtual container) and an administrative unit pointer which indicates the offset of the payload frame start relative to the multiplex section frame start. Two administrative u
38、nits are defined. The AU-4 consists of a VC-4 plus an administrative unit pointer which indicates the phase alignment of the VC-4 with respect to the STM-N frame. The AU-3 consists of a VC-3 plus an administrative unit pointer which indicates the phase alignment of the VC-3 with respect to the STM-N
39、 frame. In each case, the administrative unit pointer location is fixed with respect to the STM-N frame. 3.2.7 administrative unit-n (AU-n) pointer: Administrative unit pointer which indicates the offset of the payload frame start relative to the multiplex section frame start. See ITU-T G.707. 3.2.8
40、 agent: Part of the MAF which is capable of responding to network management operations issued by a manager and may perform operations on managed objects, issuing events on behalf of managed objects. The managed objects can reside within the entity or in another open system. Managed objects from oth
41、er open systems are controlled by a distant agent via a local manager. All S.NEs will support at least an agent. Some S.NEs will provide managers and agents (being managed). Some S.NEs (e.g., regenerators) will only support an agent. 3.2.9 alarm indication signal (AIS): A code sent downstream in a d
42、igital network as an indication that an upstream failure has been detected and alarmed. It is associated with multiple transport layers. NOTE See ITU-T G.707 for specific AIS signals. 3.2.10 asynchronous interface: These interfaces provide an output signal with frequency that is not traceable to a p
43、rimary reference clock (PRC) and that meets the frequency offset requirements given in ITU-T G.703. 4 Rec. ITU-T G.780/Y.1351 (03/2008) 3.2.11 automatic protection switching (APS) controller: That part of a node that is responsible for generating and terminating information carried in the APS protoc
44、ol and implementing the APS algorithm. 3.2.12 automatic protection switching (APS) request: That set of signals into an APS controller that determines its behaviour. An APS request can be either an externally initiated command or an automatically initiated command. 3.2.13 automatic protection switch
45、ing (APS): Autonomous switching of a signal between and including two MSn_TT, Sn_TT, or Sm_TT functions, from a failed working trail/SNC to a protection trail/SNC and subsequent restoration using control signals carried by the K-bytes in the MSOH, HO POH, or LO POH. 3.2.14 automatically initiated co
46、mmand: An APS request that is initiated by any one of the following: 1) multiplex section performance criteria; 2) local equipment performance criteria; or 3) received bridge requests. 3.2.15 auto-provisioning: The assignment of values to parameters within a network element, without those values bei
47、ng specifically entered externally by a user. 3.2.16 background block error (BBE): An errored block not occurring as part of an SES. 3.2.17 background block error ratio (BBER): The ratio of BBE in available time to total blocks in available time during a fixed measurement interval. The count of tota
48、l blocks excludes all blocks during SESs. 3.2.18 bidirectional protection switching: A protection switching architecture in which, for a unidirectional failure (i.e., a failure affecting only one direction of transmission), both directions (of the “trail“, “subnetwork connection“, etc.) including th
49、e affected direction and the unaffected direction, are switched to protection. 3.2.19 bidirectional ring: In a bidirectional ring, normal routing of the normal traffic signals is such that both directions of a bidirectional connection travel along the ring through the same nodes, but in opposite directions. 3.2.20 bit interleaved parity-X (BIP-X): BIP-X code is defined as a method of error monitoring. With even parity an X-bit code is generated by th
