1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.805 (03/2000) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital networks - General aspects Generic functional architecture of transport networks ITU-T Recommendation G.805 (Form
2、erly CCITT Recommendation) ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL, TELEPHONE CONNECTIONS AND CIRCUITS TRANSMISSION SYSTEMS INDIVIDUAL, CHARACTERISTICS OF INTERNATIONAL, CARRIER TELEPHONE SYSTEMS ON METALLIC LINES GENERAL CHARACTERIST
3、ICS COMMON TO ALL ANALOGUE CARRIER- GENERAL CHARACTERISTICS OF INTERNATIONAL, CARRIER TELEPHONE METALLIC LINES SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY TESTING EQUIPMENTS TRANSMISSION MEDIA CHARACTERISTICS DIGITAL, TERMINAL,
4、 EQUIPMENTS DIGITAL, NETWORKS G. 1OM. 199 G.20M.299 G.30M.399 G.40M.449 G.45M.499 G.50M.599 G.60M.699 G.70M.799 G.80M.899 General aspects G.80-G.809 Design objectives for digital networks Quality and availability targets Network capabilities and functions SDH network characteristics Management of tr
5、ansport network SDH radio and satellite systems integration Optical transport networks DIGITAL, SECTIONS AND DIGITAL, LINE SYSTEM G.8 1 M.8 19 G.82M.829 G.83M.839 G.84M.849 G.85M.859 G.86M.869 G.87M.879 G.90M.999 For further details, please rer to the list of ITD-T Recommendations. ITU-T Recommendat
6、ion G.805 Generic functional architecture of transport networks Summary This Recommendation describes the functional architecture of transport networks in a technology independent way. The generic functional architecture may be used as the basis for a harmonized set of functional architecture Recomm
7、endations for ATM, SDH, PDH transport networks, and a corresponding set of Recommendations for management, performance analysis and equipment specification. Source ITU-T Recommendation G.805 was revised by ITU-T Study Group 13 (1997-2000) and approved under the WTSC Resolution 1 procedure on 10 Marc
8、h 2000. ITU-T G.805 (03/2000) 1 FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, ope
9、rating and tariff questions and issuing Recommendations 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 ITU-T study groups which, in turn
10、, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSC Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE
11、In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may in
12、volve the 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 Re
13、commendation, ITU had not received notice of intellectual property, protected 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 strongly urged to consult the TSB patent database
14、. o ITU 2001 All 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 fi-om ITU. 11 ITU-T G.805 (03/2000) CONTENTS 1 2 3 4 5 5.1 5.2 5.3 5.4 5.5 6 6.1 6.2
15、6.3 7 7.1 7.2 Scope . References . Terms and definitions . Abbreviations Functional architecture of transport networks Introduction . Architectural components . 5.2.1 Topological components 5.2.2 Transport entities . 5.2.3 Transport processing functions 5.2.4 Reference points Partitioning and layeri
16、ng . 5.3.1 Introduction 5.3.2 Partitioning concept . 5.3.3 Layering concept Connection supervision . 5.4.1 Connection monitoring techniques 5.4.2 Connection monitoring applications Layer network intenvorking Application of concepts to network topologies and structures . PDH supported on SDH layer ne
17、tworks . ATM supported on SDH layer networks ATM supported through ATM inverse multiplexing Transport network availability enhancement techniques Introduction . Protection 7.2.1 Trail protection 7.2.2 Subnetwork connection protection Appendix I . Formal description of the architecture . I . 1 Introd
18、uction . 1.2 General definitions 1.3 Reference points 1.4 Others ITU-T G.805 (03/2000) Page 1 1 1 5 5 5 5 6 10 11 12 14 14 16 20 25 25 28 32 33 33 35 37 38 38 39 39 40 43 43 43 45 45 . 111 1.5 Topological components . 1.7 Transport processing functions . 1.8 Bibliography 1.6 Transport entities Annex
19、 1.A . A short introduction to Z . I.A.l Introduction I.A.2 Example # 1 I.A.3 Example #2 Page 45 47 48 48 49 49 49 50 iv ITU-T G.805 (03/2000) ITU-T Recommendation G.805 Generic functional architecture of transport networks 1 Scope A telecommunications network is a complex network which can be descr
20、ibed in a number of different ways depending on the particular purpose of the description. This Recommendation describes the network as a transport network from the viewpoint of the information transfer capability. More specifically, the functional and structural architecture of transport networks a
21、re described independently of networking technology. This Recommendation describes the functional architecture of transport networks in a technology independent way. The generic functional architecture of transport networks should be taken as the basis for a harmonized set of functional architecture
22、 Recommendations for ATM, SDH, PDH networks, and a corresponding set of Recommendations for management, performance analysis and equipment specification. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisi
23、ons 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 investigate the possibility of applying the most recent edition of the Recommendat
24、ions and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. - - - - - - - - - ITU-T G.702 (1988), Digital Hierarchy bit rates. ITU-T G.703 (1 998), Physical/electrical characteristics of hierarchical digital interfaces. ITU-T G.707 (1996), Netw
25、ork node interface for the synchronous digital hierarchy (SDH). ITU-T 1.320 (1993), ISDNprotocol reference model. ITU-T 1.32 1 (199 i), B-ISDNprotocol reference model and its application. ITU-T 1.324 (199 i), ISDN network architecture. ITU-T 1.340 (1988), ISDN connection types. ITU-T 1.361 (1999), B
26、-ISDNATMlayer speczjkation. ITU-T X.200 (1994) I ISO/IEC 7498-1:1994, Information technology - Open systems interconnection -Basic Reference Model: The basic model. 3 Terms and definitions This Recommendation defines the following terms: NOTE 1 - The terms used here are specific to this Recommendati
27、on and should not be confused with the same terms used in, for example, ITU-T 1.320,1.321,1.324 and 1.340. NOTE 2 - Where a definition contains a term which is itself defined, that term is given in quotation marks. NOTE 3 - The terms can be further qualified by reference to a specific layer network
28、by adding the appropriate layer network qualifier (e.g. SDH higher-order path termination, PDH 44 736 kbit/s path termination, ATM virtual path connection). ITU-T G.805 (03/2000) 1 NOTE 4 - All architectural components are bidirectional unless qualified by the term sink or source or unidirectional .
29、 3.1 access group: A group of Co-located “trail termination“ functions that are connected to the same “subnetwork“ or “link“. 3.2 access point: A “reference point“ that consists of the pair of Co-located “unidirectional access“ points, and therefore represents the binding between the trail terminati
30、on and adaptation functions. 3.3 adaptation: A “transport processing function“ that consists of a Co-located adaptation source and sink pair. 3.4 adaptation sink: A “transport processing function“ which presents the client layer network characteristic information at its output by processing the info
31、rmation presented at its input by the server layer network trail. 3.5 adaptation source: A “transport processing function“ which accepts client layer network characteristic information at its input and processes it to allow transfer over a trail (in the server layer network). 3.6 adapted information
32、: a signal which is transferred on “trails“. The specific formats will be defined in the technology specific Recommendations. 3.7 administrative domain: For the purposes of this Recommendation an administrative domain represents the extent of resources which belong to a single player such as a netwo
33、rk operator, a service provider or an end-user. Administrative domains of different players do not overlap amongst themselves. 3.8 architectural component: Any item used in this Recommendation to generically describe transport network functionality. 3.9 binding: A direct relationship between a “tran
34、sport processing function“ or “transport entity“ and another “transport processing function“ or “transport entity“ which represents the static connectivity that cannot be directly modified by management action. 3.10 characteristic information: A signal with a specific format, which is transferred on
35、 “network connections“. The specific formats will be defined in the technology specific Recommendations. 3.11 clientherver relationship: The association between layer networks that is performed by an “adaptation“ function to allow the link connection in the client layer network to be supported by a
36、trail in the server layer network. 3.12 connection: A “transport entity“ which consists of an associated pair of “unidirectional connections“ capable of simultaneously transferring information in opposite directions between their respective inputs and outputs. 3.13 connection point: A “reference poi
37、nt“ that consists of a pair of Co-located “unidirectional connection points“ and therefore represents the binding of two paired bidirectional “connections“. 3.14 connection supervision: The process of monitoring the integrity of a “connection“ or “tandem connection“ which is part of a “trail“. 3.15
38、dedicated protection: A protection architecture that provides capacity dedicated to the protection of traffic-carrying capacity (1 + 1). 3.16 dual ended operation: A protection operation method which takes switching action at both ends of the protected entity (e.g. “connection“, “path“), even in the
39、 case of a unidirectional failure. 3.17 layer network: A “topological component“ that represents the complete set of access groups of the same type which may be associated for the purpose of transferring information (see 5.2.1.1). 2 ITU-T G.805 (03/2000) 3.18 link: A “topological component“ which de
40、scribes a fixed relationship between a “subnetwork“ or “access group“ and another “subnetwork“ or “access group“. 3.19 link connection: A “transport entity“ that transfers information between “ports“ across a link. 3.20 management domain: A management domain defines a collection of managed objects w
41、hich are grouped to meet organizational requirements according to geography, technology, policy or other structure, and for a number of functional areas such as configuration, security, (FCAPS), for the purpose of providing control in a consistent manner. Management domains can be disjoint, containe
42、d or overlapping. As such the resources within an administrative domain can be distributed into several possible overlapping management domains. The same resource can therefore belong to several management domains simultaneously, but a management domain shall not cross the border of an administrativ
43、e domain. 3.21 matrix: It represents the limit to the recursive partitioning of a subnetwork. 3.22 matrix connection: A “transport entity“ that transfers information across a matrix, it is formed by the association of “ports“ on the boundary of the matrix. 3.23 network: All of the entities (such as
44、equipment, plant, facilities) which together provide communication services. 3.24 network connection: A transport entity formed by a series of contiguous “link connections“ andor “subnetwork connections“ between “termination connection points“. 3.25 pairing: A relationship between sink and source “t
45、ransport processing functions“ or two contra directional unidirectional “transport entities“ or between “unidirectional reference points“ which have been associated for the purposes of bidirectional transport. 3.26 path layer network: A “layer network“ which is independent of the transmission media
46、and which is concerned with the transfer of information between path layer network “access points“. 3.27 port: It consists of a pair of unidirectional ports. 3.28 reference point: An architectural component, which is formed by the binding between inputs and outputs of transport processing functions
47、andor transport entities. 3.29 shared protection: A protection architecture using m protection entities shared amongst n working entities (m:n). The protection entities may also be used to carry extra trafic when not in use for protection. 3.30 single ended operation: A protection operation method w
48、hich takes switching action only at the affected end of the protected entity (e.g. “trail“, “subnetwork connection“), in the case of a unidirectional failure. 3.31 subnetwork connection protection: A protection type that is modelled by a sublayer that is generated by expanding the “subnetwork“ “conn
49、ection point“. 3.32 sublayer: A set of additional transport processing functions and reference points encapsulated within a layer network. It is created by decomposition of transport processing functions or reference points. 3.33 subnetwork: A topological component used to effect routing of a specific characteristic information. 3.34 subnetwork connection: A “transport entity“ that transfers information across a subnetwork, it is formed by the association of “ports“ on the boundary of the subnetwork. 3.35 tandem connection: An arbitrary series of contiguous “link connections“ andor “subn
