The Information Services Supermarket - A Trial TINA-C Design

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  page 1 of 13 The Information Services Supermarket - a trial TINA-C Design Mark Bagley, Ian Marshall, Martin Yates and Julian Hill,BT LabsMartlesham HeathIpswich, IP5 7REUKTel +44 473 646505Fax +44 473 637400 Abstract This paper describes the design steps we have found to be necessary to create a practical design for realisation of a TINA-C like service environment supporting an advanced information service (Travel Agent). It was found to be important to start by constructing an enterprise model which delineated theroles of the stakeholders in the service. The next step was to construct a detailed service operationscenario within the enterprise model. Only after this work was complete was it possible to commencedetailed system designs and make use of the technical content of the TINA-C deliverables. In particular it was found that management aspects could not be designed without a very clear idea of what was to bemanaged and why. A number of critical interfaces requiring standardisation have been identified duringthe work and the the nature of the standards needed is explored in some detail in the paper. The designsare now being implemented in an Asynchronous Transfer Mode (ATM) network environment on an Object  Management Group (OMG) Common Object Request Broker Architecture(CORBA) based Distributed Processing Environment (DPE). Introduction Until recently the principal barriers to mass market introduction of commercial information services havebeen technological and financial. Now that easy to use multimedia applications for cheap terminals arereadily available, the Internet is experiencing explosive growth, and it might appear that the problems aresolved. However, finding and retrieving the desired information is still time consuming, and no guaranteesof correctness are available. A commonly quoted solution to the problems is the use of intelligentnetworked agents [1,2,4,8,9,13] as exemplified by TINA-C and General Magic. The agents required areextremely complex and sophisticated and considerable design effort must be expended before they can berealised in a concrete implementation. This paper will describe the early (abstract) design phases of aproject intended to realise a prototype commercial telecommunications/information service environmentusing intelligent networked agents based on the TINA-C architecture [2,4]. We call this environment anInformation Services Supermarket. The first section contains a generic description of a well knownhistoric information service to illustrate the problems that must be solved. This is followed by an enterprisemodel for this service, which was derived by analogy with service offerings in the retail and distributionsectors [5,7]. The enterprise model has allowed us to breakdown the design problem and expose a numberof key interfaces. In order to progress to detailed design it was necessary to create a detailed examplescenario. We chose to use a travel agency as the example on the grounds that it would allow most of theknown issues to be explored and generalised for use in other examples. The enterprise model presentationis followed by a section giving an overview of the scenario and the associated session designs which arecurrently considered outside the scope of TINA but which need to be in place before the bulk of the TINAoutput can be used. It is helpful to use TINA principles at this stage of the design. The next sectionelaborates on the design of the supermarket, which uses a substantial range of components from the TINAservice and management architectures and refines the architectural concepts towards a practical realisation.A few pointers to concurrent implementation experiments are also recorded. The next sections of the paper  page 2 of 13 explore and examine the key interfaces and their properties. Then finally we assess the benefits of TINA-Cin the work we have done and indicate areas where additions and improvements to TINA-C would bebeneficial. Historic Information Services When telephone networks were first introduced to an unsuspecting public they were very different to thenetworks of today. To use the network one picked up a microphone, wound a handle to charge a batteryand said operator . The instrument would respond by asking you to state your desires. Any reasonabledesire for information or communication could be satisfied, either directly (as in Oh the doctor is at MrsSmith’s, I’ll connect you to there) or indirectly (as in I don’t know but I know a man who does ). This wasat the time a wonderful and much loved service, however, as the networks grew problems started to appear. ã The service became inconsistent (it was better in small villages than large towns) ã The service became expensive (it was predicted that 50% of the population would betelephone operators by the year 2000) ã The service became selective rather than impartial ã The service became a major management headacheSince the service was not earning revenue (no Electronic Fund Transfer Point Of Sale!) it was withdrawnas soon as automatic switches (Strowger) became available. The users were pleased since their callsbecame private and the service was cheaper and more consistent. Nevertheless the loss of the informationmine that operators once represented was regretted.It is proposed that automation would solve many of the problems since an intelligent machine; ã Can provide access to large amounts of up to date information quickly ã Does not need training, sick leave etc. ã Can be copied any number of times to provide universal access ã Can be paid electronically ã Is always as impartial as its makers intended ã etc.Indeed aspects of the service have already been reintroduced in an automated form, whenever it wasfeasible and cost effective (e.g. Yellow Pages and Intelligent Network (IN) [3]). The work we will describeis intended to realise an automated version of all aspects of a suite of information services similar to thatdescribed above. The first stage is to construct an enterprise model and break the problem down into moremanageable domains. Enterprise Model The enterprise model we have developed was derived by interpreting the service above as informationretailing and attempting to represent the activities of a hardware retailer/distributor in the model. Thisanalogy is the source of the name Information Services Supermarket . It was felt that basing the model onan existing implementation in this way would enable productive reuse of existing technology andknowledge and thus minimise the effort involved. Analysis of this enterprise model has led us to the viewthat we need a distributed object oriented implementation with well defined open interfaces. Many (but notall) of the concerns are addressed by TINA-C so we have used TINA-C as the basis of our designs(elaborated in the next section). The model is shown in Fig. 1  page 3 of 13 User Domain Connections, Network Resources Service 1  Information Services Supermarket  prefs terminal   terminal  agent  Buyer AgentsUser Agent  Management of Services  Network Domain Retailer Domain Provider Domain Service 2Service 3Service N  User Fig. 1. Enterprise modelThere are four separate domains depicted in the model; ã The user domain ã The network domain ã The provider domain ã The retailer domainThe user domain represents the domain of interest of users of the services available in the retail domain. Itcontains the user and items which he owns or controls such as his personal profile and applications, and histerminal(s). It also contains a terminal agent which can negotiate with the retail domain and communicatethe capabilities of the users domain to the retail domain when necessary. This agent is intended to includethe terminal agent concepts from the TINA-C architecture. We envisage that the terminal agent may besupplied by the retailer but owned by the user (or his subscriber).The network domain represents the domain of interest of the owners of the network used to conveymessages from the user to the retailer or other users. It is envisaged that by analogy with normal retailing the user will not have a direct contractual relationship with the network. Instead the network should be regarded as a subcontractor to the retailer. Initial access of the user to the retailer is regarded asbeing achieved by services such as freephone which are paid for by the retailer. The network domain isintended to contain the network hardware and associated software, such as connection co-ordinators andmanagers from the TINA-C connection management architecture. It also needs to contain connectioncontrol features form IN Capability Set 1/2 [3] to enable freephone and mobility.The provider domain represents the domain of interest of sources of the services which can be purchased inthe retail domain. It contains a set of disparate service providers, each of which provides agents which cannegotiate with buyers in the retail domain on supply and payment for services, and similar issues. It isprobably a specialisation of the retailer domain with a restricted set of customers and service offerings.This allows the purchase of composite services.  page 4 of 13 The retailer domain is perhaps the most interesting. It is intended to represent the domain of interest of aretailer who; ã Facilitates access to information and communication services and associated tools ã Acts as a middleman or broker for service providers and network providers ã Offers customised guaranteed services to individual customers ã Manages the services ã etc.It contains a set of intelligent agents which can respond to user and manager demands on an individualbasis. These include the TINA-C user agent, service session manager and communications sessionmanager. It also contains a set of management processes which allow managers to; ã Monitor activity ã Make configuration changes ã Specify and enforce policies ã Maintain quality, performance, access etc. as demand and resources vary ã Enforce payment and security related mechanisms ã Assess interactions and add links to third parties ã Advertise services ã etc.A more complete list can be obtained by analysing the activities of existing retailers. We have found thatthe above services can be supported by the existing TINA-C resource, fault and configuration concepts,and that the concepts can be reused for high level designs of security, account and performancemanagement processes. This retailer can be considered almost entirely analogous to the arrangement asupermarket (say a food retailer) has with suppliers of products and the services it offers to those suppliersand the buyers of the products (subscribers). Services (products) are offered by the supermarket (say BT) onbehalf of the service providers to users (end-users that are associated with a subscriber). The service offeredcan in theory be physically situated anywhere, so it could be resident in the service providers domain andaccessed via the supermarket, and indeed in practice this is the most convenient logical position for it.Physically there are benefits to the service provider to have the service resident in the supermarket. This isbecause if the supermarket operator is also a network operator or has access to a large network then theservice is potentially available to a wide range of users.The model illustrates several important inter domain interfaces. These include; ã The user domain - retailer domain interface ã The retailer domain - provider domain interface ã The retailer domain - network domain interface ã The user domain - provider domain interface (mediated by the retailer)In order to support flexible use of services from different providers and connections across differentnetworks using user domain terminals and applications of diverse types, these interfaces need to be open.By this we mean that the capabilities required at the interface can be described using a set of defined termsdrawn from published standards and agreements. A key concern is to establish the degree of opennessrequired at the inter domain interfaces and agree how it can be achieved. The understanding of theinterfaces and their properties which we have gained from our design work, and the degree to which TINA-C enables them to be open is the main topic of the final part of this paper. Specific Service Scenario In order to render the design efforts specific, and easily resolve the issues that arise, we have found it usefulto define a scenario for the use of the above Enterprise Model and Generic Information Service capability.The scenario (at its highest level) defines the retailer as a franchise holder for a “strongly brand imaged”travel company (whose branches are normally franchised). This travel company (TravelCo) has existingcontracts with third parties for the provision of various specialised services (such as brochure providers,video footage provider, foreign exchange provider, Airline Booking, etc), and has provided an applicationthat can be made available to the user from a server in the retailer domain (TINA-C Service Factory

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Jul 12, 2018
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