1、 STDaITU-T RECMN G-702-ENGL 1975 4862573 Ob23320 807 INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.902 (1 1/95) SERIES G: TRANSMISSION SYSTEMS AND MEDIA Digital transmission systems - Digital sections and digital line system - General Framework recomme
2、ndation on functional access networks (AN) Architecture and functions, access types, management and service node aspects ITU-T Recommendation G.902 (Previously MCCITT Recommendation,) lTU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA VRANSMISSION MEDIA CHARACTERISTICS General Symmetric c
3、able pairs Land coaxial cable pairs Submarine cables Optical fibre cables G .600-G . 609 G.6 10-G.619 G.620-G.629 G.630-G.649 G.650-G.659 Characteristics of oDtical commnents and sub-svstems G.660-G.699 TIERMINAL EQUIPMENTS General Coding of analogue signals by pulse code modulation Coding of analog
4、ue signals by methods other than PCM Principal characteristics of primary multiplex equipment Principal characteristics of second order multiplex equipment Principal characteristics of higher order multiplex equipment Principal characteristics of transcoder and digital multiplication equipment Opera
5、tions, administration and maintenance features of transmission equipment Principal characteristics of multiplexing equipment for the synchronous digital hierarchy Other terminal equipment General aspects Design objectives for digital networks Quality and availability targets Network capabilities and
6、 functions SDH network characteristics DIGITAL NETWORKS (3.700-G.799 G .700-G.709 G.710-(3.719 G .720-G . 729 G.730-G.739 G.740-G.749 G.750-G.759 G.760-G.769 G.770-G.779 G.780-G.789 G.790-G .799 G.800-G.899 G.800-G. 809 G.8 10-G.8 19 G.820-G.829 G.830-G.839 G.840-G.899 Parameters for optical fibre c
7、able systems G.9 10-G.919 Digital sections at hierarchical bit rates based on a bit rate of 2048 kbit/s G.920-G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930-G.939 Digital line systems provided by FDM transmission bearers G.940-G.949 Digital line systems G.950-G.
8、959 Digital section and digital transmission systems for customer access to ISDN G.960-G.969 Optical fibre submarine cable systems G.970-G.979 Optical line systems for local and access networks G.980-G.999 For further details, please refer to ITU-T List of Recommendations. STD*ITU-T RECMN G-702-ENGL
9、 1775 = iBb2571 Ob21122 bA2 FOREWORD The -T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (IT). The IT-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations on them with a view to standardi
10、zing 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 their turn, produce Recommendations on these topics. The approval of Recommendations by the
11、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 G.902 was prepared by IT-T Study Group 13 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 2nd of November 1995. NOTE In this Recommendat
12、ion, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O IT 1996 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, includin
13、g photocopying and microfilm, without permission in wnting from the ITU. Recommendation G.902 (11/95) i STD-ITU-T RECMN G.702-ENGL 1775 H 48b2571 ObZL123 517 5 6 7 CONTENTS Scope References Definitions and abbreviations . 3.1 Definitions 3.2 Abbreviations Access Network functional architecture and r
14、elated functions 4.1 Introduction 4.2 General Access Network architecture and boundaries . 4.3 General protocol model for Access Network 4.4 Definition of individual functional groups . 4.4.1 User Port Function 4.4.2 Service Port Function 4.4.3 Core Function 4.4.4 Transport Function 4.4.5 AN System
15、Management Function . 4.5 Access Network interfaces 4.5.1 User network interface 4.5.1.1 Individual UNI 4.5.1.2 Shared UNI . 4.5.2 Service Node interface 4.5.3 43 interface . Support of access types in Access Networks . Transport capabilities . 6.1 Transport layer model . 6.2 Management, control and
16、 operation issues 7.1 Functional Management Architecture . 7.2 Requirements for operation and maintenance of access networks 7.3 Description of the AN Management Functions Transport layer functions and requirements . 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 Management of the User Port Function 7.3.1.1 User Por
17、t Control 7.3.1.2 User Port Monitoring 7.3.1.3 User Port related Status Events . Management of the Core Function 7.3.2.1 Core Function control . 7.3.2.2 Core Function monitoring . Management of Service Port Function 7.3.3.1 Service Port Control 7.3.3.2 Service Port Monitoring 7.3.3.3 Service Port re
18、lated Status Events Management of the Transport Functions 7.3.4.1 Transport Function Control . 7.3.4.2 Transport Function monitoring . Management of the AN System Management Function . 7.3.4.3 7.3.5.1 7.3.5.2 Transport Function related Status Events . AN System Management Function control . AN Syste
19、m Management Function monitoring 7.4 Management Information flows Page 1 2 2 2 4 6 6 6 6 7 8 9 9 9 9 10 10 10 10 11 11 11 11 11 12 12 12 14 14 15 15 15 15 16 16 16 16 16 16 16 16 16 17 17 17 17 17 17 11 Recommendation (2.902 (11195) - STD.ITU-T RECMN G.7Z-ENGL 1775 m Lib2571 Ob2112Li Li55 8 Service
20、Node interfaces and service node requirements Types of service nodes 8.1.1 Service specific Service Nodes . 8.1.2 Modular Service Nodes . 8.2 Service Node Interfaces 8.1 Annex A . Access Network architecture aspects concerning access types and access function . The access architecture and the releva
21、nt Recommendations A.l A.2 A.3 A.4 Access connection element implementation cases The ET function in the different access connection element implementation cases . Access network performance and maintenance Access network error performance . copper drop . A.5 Multi-hosting and multi-homing . Accesse
22、s for on-demand service and leased line A.4.1 A.4.2 User port maintenance and performance in case of access networks with and without A.6 Appendix I . Support of access types in Access Networks 1.1 status 1.2 UNI . 1.3 Access digital section 1.4 Information type . 1.5 Transfer mode . 1.6 Direction .
23、 1.7 Required channel rate or cell rate . Appendix II - Examples of functional models of lower network layers of access network . Appendix III - Examples of different Access Network configurations Multiplexing on transmission media layer Multiplexing on path layer III.2.1 Remote access connection ii
24、I.2.2 Remotely connected access . III.3 Full integration 1II.I III.2 Page 19 19 19 19 20 21 21 23 24 26 26 26 26 27 27 28 28 28 28 28 28 28 33 38 38 38 38 38 38 Recommendation G.902 (11/95) . 111 STD-ITU-T RECMN G.702-ENGL 1775 m L(8b2573 Ob23325 391 m SUMMARY The evolution of the existing network i
25、n the local area to other switching and transport technologies requires a new concept for the implementation of access networks as a common infrastructure for ali types of user accesses to the service nodes. Although there is a strong trend to use optical fibres as the transport medium for an access
26、 network, other transmission media shall not be excluded from the access network concept. Access networks shall be capable of supporting existing types of accesses and digital bearer capabilities as well as broadband accesses. The objective of this Recommendation is to describe an access network con
27、cept that provides flexibility towards future access types, e.g. for interactive video services. Access networks need to be connected to the service nodes by use of interfaces (Service Node Interfaces) with flexible multiplexing and/or concentration capability. Existing service node interfaces may n
28、ot be sufficient for upcoming service demands especially not if broadband access types need to be incorporated. iv Recommendation G.902 (11/95) Recommendation G.902 FRAMEWORK RECOMMENDATION ON FUNCTIONAL ACCESS NETWORKS (AN) ARCHITECTURE AND FUNCTIONS, ACCESS TYPES, MANAGEMENT AND SERVICE NODE ASPEC
29、TS (Geneva, 1995) 1 Scope This Recommendation defines the functional Access Networks and the functions and requirements above the transmis- sion media layer according to Recommendation G.803. The layers within transmission media layer are outside the scope of this Recommendation. This Recommendation
30、 identifies and describes: - - - - - the architecture of the Access Network and its relation to the Service Nodes; the access types considered to be supported by the Access Network; the bearer transport capabilities and requirements; the management concept and requirements in conjunction with the Se
31、rvice Nodes; and the operation and control requirements of accesses, which should be supported by the detailed functional specification of Access Networks and identified interfaces in the Access Network and of the Service Node Interfaces. This concept does not constrain implementation of the provisi
32、ons and requirements in equipment using different transmission media or technology. Nevertheless other Recommendations may be applicable for the implementation of the transmission media layer aspects. The purpose of this Recommendation is to provide the framework for the future work regarding: - ser
33、vice node interface Recommendation; - access network Recommendation; - service node Recommendation; - user network interface Recommendation; - - - access network internal interface Recommendation; definition of access types; and definition of access bearer capability requirements. Because new techno
34、logies for switching, transport and control are evolving rapidly it is important to define this framework in a timely way as a basis for specifying interfaces. Nevertheless, the same speed of evolution that makes it necessary to have a timely framework document assures that whatever is written only
35、reflects the current state of technology. Therefore, it will be subject to the need for frequent updating in order not to constrain that evolution. The functional requirements for the Access Network are defined for the handling and transport of digital signals only. Analogue signals and bearers shal
36、l either be converted to digital signals or bearers, which may then be supported by the functional Access Network, or may be combined with the transport signals of the functional Access Network on the media dependent network layer for the transport on the same medium. This shall not have any impact
37、on the requirements, functions and procedures of the functional Access Network and is therefore not within the scope of this Recommendation. The functional Access Network can support multi-hosting, but as a consequence of the definition that the Access Network does not interpret signalling, multi-ho
38、ming, as defined in clause 3, is not supported. Annex A describes Access Network architecture aspects concerning access types and access functions for the support of the defined handling of access types. Appendix I provides the current information available concerning access types and access bearer
39、capability requirements which may be supported in access network implementations. The tables need frequent updating according to the status of work on other standards in -T. Recommendation G.902 (11/95) 1 Appendix II gives examples of the lower network layers of access networks. Appendix III gives e
40、xamples of configurations that integrate circuit mode type and ATM type accesses into one Access Network using different network layers. 2 References The following Recommendations contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of p
41、ublication, the editions indicated were valid. All Recommendations are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations listed below. A list of the currently valid ITU-T Recommenda
42、tions is regularly published. 11 ITU-T Recommendation G.803 (1993), Architecture of transport networh based on the Synchronous Digital Hierarchy (SDH). 2 ITU-T Recommendation I. 112 (1993), Vocabulary of ferms for ISDNs. 3 ITU-T Recommendation 1.414 (1993), Overview of Recommendations on layer I for
43、 ISDN and B-ISDN customer accesses. CCITT Recommendation M.3010 (1992), Principles for a telecommunications management network. ITU-T Recommendation G.960 (1993). Access digital section for ISDN basic rate access. ITU-T Recommendation G.962 (1993), Access digital section for ISDNprimary access at 20
44、48 kbids. IT-T Recommendation G.963 (1993), Access digital section for ISDNprimary access at 1544 kbith. IT-T Recommendation G.964 (1994), V-interfaces at the digital Local Exchange (LE) - V5. I interface (based on 2048 kbids) for the support ofAccess Network (AN). IT-T Recommendation G.965 (1995),
45、V-interfaces at the digital Local Exchange (LE) - V5.2 interface (based on 2048 kbith) for the support ofAccess Network (AN). ITU-T Recommendation 4.512 (1993, Digital exchange interfaces for subscriber access. IT-T Recommendation 4.2512 I), Network node interfaces for subscriber access. ITU-T Recom
46、mendation G.805 (1995), Generic functional architecture of transport networks. ITU-T Recommendation 1.430 (1993), Basic user-network interface - Layer I specification. 4 5 6 7 8 9 101 1 11 121 131 3 Definitions and abbreviations 3.1 Definitions For the purposes of this Recommendation, the following
47、definitions apply in addition to those Recommendations listed in clause 2. 3.1.1 access (user access): See Recommendation 1.1 12. See also ISDN Customer Access in Recommendation 1.414. 3.1.2 access bearer capability: The maximum information transport capacity supported by the access for a particular
48、 customer (which includes the Access Network and the relevant Service Node) at a particular UNI. This access bearer capability may be used for one or more than one connection at the same point in time and cannot exceed the UM net bit rate, but may be lower to meet the specific needs of the customer
49、and/or the provider(s) of the access. 3.1.3 access bearer structure: The structure of the access bearer capability for application information for services, signalling, operation and maintenance, as required for a particular customer access and UNI. The structure may be according to the principles of circuit mode, packet mode, frame mode, Asynchronous Transfer Mode (ATM) or any mix of several modes. ) Presently at the stage of draft. 2 Recommendation G.902 (11/95) STD-ITU-T RECMN G.902-ENGL 1775 m Li8b2571 Ob21128 OTO m 3.1
