Result at a Glance
- To form a common architectural basis for the specification of the InteliGrid services and applications
- Basic assumption is that software not only has to model the real world, it also has to model the technical resources that this software is using
- Based on the conceptual analysis of the state-of-the-art in the areas of SOA, semantic web and virtual organizations
- Technically commits to Web Services/WSRF technologies
- Layered architecture: a problem domain layer, various conceptual models and ontologies, the software layer which includes applications and services, and the layer of basic hardware and software resources
- Common conceptual model for all InteliGrid services and applications
- Basic definition of different required ontologies
The main idea behind the InteliGrid architecture framework (right) is that there are basically four kinds of things that are of concern:
- The real world - limited of course to the domain that the InteliGrid system is addressing. In order that IT can assist in handling all this, the real world needs to be conceptually modelled
- Conceptual layers. Containing things that exist in the form of standards, ideas, graphs, schemas, ontologies, notions etc. It does not contain services or any other kind of executable code, juts a formal encoding of the concepts from all the layers.
- Software layer. Consists of software that can be compiled, installed, executed, that runs and communicates with other software. In this software the schemas derived from the conceptual layer would be used, the software would commit to the ontologies defined in the conceptual layer or the software would conform to the standards defined in the conceptual layer.
- Basic resource layer. To run software, IT resources are needed, including hardware, firmware and software that are on too basic level to be of interest to the InteliGrid project but are needed to run the applications and services defined in the layer above.
InteliGrid is delivering a generic grid-based integration and web semantic-based interoperability platform for creating and managing networked Virtual Organizations. In order to provide VO organizational framework that facilitates the coordination and cooperation between virtually partnering companies we have identified a set of actors and players based on requirement analysis. The InteliGrid service-oriented architecture (SOA) is presented on the figure below. It includes various components and their interfaces. The following common characteristics can be defined for all InteliGrid services as main components:
- services are modular components that can be semantically described, registered, discovered and finally used by clients,
- services can participate in specific business workflows, where the order in which are sent and received affects the outcome of the operations by a service,
- services may be completely self-contained, or they may depend on availability of other services,
- services are able to advertise details such as their capabilities, interfaces and supported communication protocols according to pre-defined concepts and ontologies,
- all capabilities provided by services as well as communication and data channels among them and clients are protected by security and message level security mechanisms.
Technically speaking InteliGrid components are deployed either at some workstation or on the grid. If on the grid it is not important where physically they are deployed, very likely the resource where they would run would be allocated dynamically. The grouping of the various services in the previous picture is by the logic of the service and does not necessarily imply who uses whom. There are three main kinds of components in the InteliGrid platform:
- business applications who are the consumers of the other components (left part of the Figure 12). Most services are accessed through portal, but access through other desktop software is possible as well.
- services that comply to WSRF or WS+GSI and talk to each other as well as to the client applications. They can be further decomposed into: (a)interoperability services (top tier) that simplify the interoperability among all services, (b) business services that are performing some value added work for a business using the InteliGrid platform, (c) middleware services offer traditional grid middleware functionality but extended with the particular needs of InteliGrid in mind. The InteliGrid Platform consists of generic Grid Middleware Services such as GAS, OGSA-DAI and GRMS based on mature grid technologies and their open source reference implementations (mostly based on Globus Toolkit).
- other resources. The bottom layer of the InteliGrid architecture consists of various physical infrastructure resources (both data/storage and computing resources) offered by suppliers to InteliGrid Platform. All these resources are available through well defined secure protocols and grid-enabled generic core services for remote data access: GridFTP and WebDAV, and also for remote application submission and control: GT2/GT4 GRAM and DSP. All core services as software components can be accessed via a network through well defined interfaces and communication protocols to provide functionality to requesters.