1、STD. ITU-T RECMN I1998 48b259L Ob52523 INTERNATIONAL TELECOMMUNICATION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES Y: GLOBAL INFORMAT Gen eral ON 834 UNION YA20 (06/98) NFRASTRUCTURE Global Information Infrastructure scenario methodology ITU-T Recommendation Y. 120 (Previously CCIlT
2、 Recommendation) _ STD-ITU-T RECMN Y.LZ0-ENGL 199 4b2591 Ob52524 770 = ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE General Y.100-Y.199 Services, applications and middleware Network aspects Interfaces and protocols Numbering, addressing and naming Operation, administration and ma
3、intainance Security Y .200-Y .299 Y.300-Y.399 Y .400-Y .499 Y.500-Y.599 Y.600-Y.699 Y.700-Y.799 For further details, please refer to ITU-T List of Recommendations. - sTD.1TU-T REC“ Y.120-ENGL 1998 4862.593 Ob52525 607 = ITU-T RECOMMENDATION Y.120 GLOBAL INFORMATION INFRASTRUCTURE SCENARIO METHODOLOG
4、Y Summary This Recommendation describes a set of graphical techniques that can be used to simply illustrate scenarios which depict a variety of interconnected network technologies, and the associated key interfaces that may be encountered in the provision of the Global Information Infrastructure (GI
5、I). Source ITU-T Recommendation Y. 120 was prepared by ITU-T Study Group 13 (1 997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 12th of June 1998. Keywords Global Information Infrastructure, GII, standardization, networks, scenarios, interfaces. FOREWORD ITU (International
6、 Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations
7、 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 their turn, produce Recommendations on these topics. The ap
8、proval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 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 In this Recommendation,
9、 the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a
10、claimed Intellectual Property Right. The 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 Recommendation, t
11、he 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. O ITU 199
12、8 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 from the IT. Recommendation Y.120 (06198) 11 STD.ITU-T RECMN Y.120-ENGL I1998 = Y862591 Ob52527
13、YBT 1 1.1 1.2 2 3 4 5 6 7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 8 8.1 8.2 8.3 9 10 10.1 10.2 10.3 10.4 10.5 11 CONTENTS Introduction The need . The purpose Scope Normative references Terms and definitions . Abbreviations . Building a scenario . Principles of description . Generic elements Interface denotation
14、 Element representation . Appliances and functional units An Example configuration of generic elements . Other dependencies . Identification of information flow(s) 7.3.1 Networks . 7.3.2 Indirect connections or associations . Types and Qualifiers . Interface classifications Sub-Type classifications
15、. Qualifiers for protocol profile designation . Service aspects Method of application . Step 2 - Initial scenario development Step 4 - Collaboration amongst organizations . Examples of use Step 1 - Initial scenario need identification . .I. Step 3 - Scenario socialization . Step 5 - Iteration Page 1
16、 1 1 2 2 3 3 4 4 4 4 5 5 .5 5 6 7 7 8 8 8 8 9 9 9 9 10 10 10 10 . Recommendation Y.120 (06/98) 111 Reco mmendation Y. 120 GLOBAL INFORMATION INFRASTRUCTURE SCENARIO METHODOLOGY (Geneva, 1998) 1 Introduction This Recommendation describes a set of techniques that can be used to graphically illustrate
17、configurations of a variety of network technologies and user appliance that may be expected to be encountered in the context of the Global Information Infrastructure (GII). The term “scenario“ has been adopted to denote a combined graphical and textual representation of such a configuration. 1.1 The
18、need In some cases the GI1 will comprise components from different industry sectors, i.e. telecommunications, information technology and entertainment. The boundaries of service provision are no longer distinct, and the convergence between the industry sectors is occurring, and more diverse service
19、delivery technologies are emerging. Because of the different backgrounds of the participants, a mutually understood methodology is required in order that scenarios can be developed and analyzed in a consistent fashion. The provision of various services by a variety of service providers, over a varie
20、ty of network technologies, from different industry sectors, makes provision of end-to-end service a significant system integration issue. In order to understand the related standards issues, it is necessary to understand the interdependencies amongst all components in the system as well as those be
21、tween immediately adjacent components at a single interface. This need can only be met by examining the interplay and inter-relationships amongst all components within a given scenario. The task can be made more manageable if a number of interacting components can be depicted in a single diagram. NO
22、TE - It is not envisaged that all situations can be fitted into a single diagram. Clearly, some step-wise refinement will be necessary in the most complex cases. However, the principle holds true for each levei of abstraction in cases where a number of different levels of abstraction are required. 1
23、.2 The purpose The purpose of a scenario is to enable specific arrangements of certain GI1 components to be illustrated. Interesting cases occur when technologies from different industries come together andor where services traditionally offered by particular providers over particular technologies a
24、re offered by non-traditional providers over non-traditional technologies. Examples of this are telephone service over cable TV network or video services over local loop networks. Other interesting cases involve the interconnection of technologies not previously interconnected and/or the non-traditi
25、onal use of certain appliances. Thus, the primary purpose of a scenario is: a identification of points that form key interconnection interfaces, access interfaces or appliance interfaces in a configuration involving a set of providers of services, networks and appliances; identification of the set o
26、f standards that could be applied at each key interface point; identification of the key standards development organizations SDOs and/or industry consortia that might desire to be involved in the standards-related system integration issues. b) c Recommendation Y.120 (06/98) 1 STD-ITU-T RECMN Y-320-E
27、NGL 3998 = 4862593 Ob52529 252 Associated with the above, related purposes include means to: d) facilitate classification of interfaces by type; e) facilitate identification of services that can be carried across interfaces; f) facilitate classification of services by type; g facilitate identificati
28、on of end points for service delivery; h) accommodate a profile of all protocols involved, either directly or indirectly, at a given interface; i document other related issues. The scope of application of the methodology described in this Recommendation is not restricted to the provision of traditio
29、nal voice, data, video services or network technologies. It is expected that this Recommendation will be used to describe a variety of situations, such as transaction processing, distributed computing, imaging, etc. 2 Scope This Recommendation provides the tools for the development of scenarios whic
30、h involve multiple networks, multiple industries and multiple Standards Development Organizations (SDOs) or standards-related industry organizations. This Recommendation provides a method and a set of conventions for the production of scenarios, involving particular combinations of network technolog
31、y, server technology and appliance technologies that are deployed in the provision of a specific service (or set of services). Generally, scenarios will: a provide a means of checking for completeness of a solution; b) facilitate the development of common solutions; c facilitate comparison amongst s
32、olutions; 4 provide a catalogue of standardized solutions to avoid unnecessary reinvention; e help to identifi gaps in the standard repertoire; f) identi joint interests amongst Standards Development Organizations (SDOs) and areas where collaboration is required; g) facilitate the investigation of i
33、nter-relationships between all elements depicted in a given scenario. Additionally, since it is envisaged that this Recommendation will be used during the cross industry, multi-SDO collaborative process, a guide for its application is also provided. NOTE - It is envisaged that this Recommendation wo
34、uld be worked on in collaboration with other SDOs and or industry organizations, and mutually adopted for the purposes of joint scenario development. 2 Recommendation Y.120 (06198) STDmITU-T RECMN Y-120-ENGL 1998 4Bb2571 Ob52530 T74 3 Normative references For further study. 4 Terms and definitions T
35、his Recommendation defines the following terms: 4.1 access network. 4.2 the service application. Examples of appliance are telephones, TV sets, computers, etc. 4.3 4.4 Access-Network Interface (ANI): An interface between a local switching network and an appliance: Appliance is the generic term used
36、to describe the terminal device employed by adaptation interface (AI): The interface between an Adaptation Unit and an Appliance. adaptation unit (AU): The unit, or function, which converts from the native On-Premise Interface (OPI) to another interface more suitable for the given appliance. 4.5 the
37、 final drop network to the customer premise. 4.6 switch, application server, appliance, etc. 4.7 backbone switching network and a local switching network. 4.8 drop-distribution interface (DI): The interface between a local GI1 element: Element is the generic term used to describe any GI1 network-to-
38、network interface type A (“I-A): The interface network-to-network interface type B (“I-B): The interface distribution network and component, e.g. network, between a long distance between a long distance backbone switching network and a peer long distance switching backbone network. 4.9 internal cust
39、omer premise network or equipment. 4.10 and the appliances. 4.11 premise-attachment interface (PAI): An interface between the external network and the on-premise interface (OPI): The interface between the on-premise network or equipment qualifier: A set of protocol descriptors. 5 Abbreviations This
40、Recommendation uses the following abbreviations: AI ANI AU DI GI1 NIU “1-A “JI-B NT PSTN Adaptation Interface Access-Network Interface Adaptation Unit Drop-Distribution Interface Global Information Infrastructure Network Interface Unit Network-to-Network Interface Type A Network-to-Network Interface
41、 Type B Network Terminating Unit Public Switched Telephone Network Recommendation Y.120 (06/98) 3 OP1 On-Premise Interface PAI Premise-Attachment Interface 6 Building a scenario A scenario is a graphic representation of a particular set andor of GI1 elements involved in the delivery of a particular
42、service. A simple example of a scenario could be the provision of voice-band service over some combination of PSTN and cable TV network components, and customers telephone and data terminal equipment. In the case of the GII, it is envisaged that a typical scenario will involve a number of networks a
43、nd appliances. The networks and appliances will, in general, be under different jurisdictions as far as industries and their respective SDOs are concerned. For example, it may be envisaged that the telecommunications, information and entertainment sectors could be involved in a given scenario. The p
44、rimary goal in building a scenario is to show the interplay of the various sectors and to provide a “picture“ of the interfaces between, and commonality amongst the various sectors involved. It is envisaged that scenarios would form the basis for collaboration and act as a repository for mutually ag
45、reed solutions. 7 Principles of description The following principles shall be used in developing a scenario. The principles are intended to be as informal and as self-explanatory as possible. The prime purpose of the principles is to achieve sufficient consistency amongst scenario developers without
46、 overburdening them with formal descriptive requirements. 7.1 Generic elements Each scenario is a primarily a reference configuration. As such it illustrates a set of technology elements, interfaces, and services. 7.2 Interface denotation The interface symbol, shown in Figure 1 shall be used to deno
47、te an interface and/or reference point between two GI1 elements. + T1311870-97 Figure lN.120 - Interface Symbol A Type and a Qualifier (or set of Qualifiers) will be associated with each instance of the interface symbol in a particular scenario. Where space permits, Types and Qualifiers will be posi
48、tioned close to the symbol, or alternatively a reference will be placed close to the symbol and the Types and Qualifiers will be listed against the appropriate reference. Examples of Basic (interface) Types include: AI Adaptation Interface ANI Access-Network Interface DI Drop-Distribution Interface
49、4 Recommendation Y.120 (06/98) “I-A Network-to-Network Interface Type A “I-B Network-to-Network Interface Type B OP1 On-Premise Interface PAI Premise-Attachment Interface Types and Qualifiers are further described in clause 8. Type + Qualifier (or Qualifier reference) T1311880-97 Figure 2N.120 - Interface symbol with Type and Qualifier In the simplest case of interconnection between only two elements, the interface symbol with its Type and Qualifier(s) will completely describe all the protocols operating over the interface between the t
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