Important editorial note: While the general principles in this document are relevant, the specific technologies discussed are in some cases outdated.
The Access Grid (AG)[1] infrastructure creates a collaborative environment designed to provide seamless, interactive group-to-group collaborations among groups that are not co-located. This enables a rich set of interactions to occur by utilizing streaming media, providing a semi-immersive environment in which the technology fades into the background. Designed to be always on, instantaneous interactions occur across widely distributed sites. In order to effectively interact across the Access Grid, users are best served by Access Grid Nodes (AGNs) conforming to a minimum set of standards to provide the seamless semi-immersive environment. Similar to other semi-immersive and fully immersive systems, the success of the Access Grid is contingent upon the degree to which these standards are achieved or exceeded. In the past AG Nodes have had to conform to a specific hardware configuration. This was to build a system that can be deployed widely enough toinvestigate the open research questions in group-to-group collaboration. Now that the AG is established, it is important to enable the investigation of alternative AG Node configurations. This document specifies the minimum functionality required for a space to be considered an Access Grid Node.
The Access Grid provides a group-to-group collaboration environment with unique features including resources provided via a spatial metaphor and the virtual collaboration spaces are persistent. The architecture is open, extensible, scalable, and leverages established standards. The Access Grid is made up into three major parts, Virtual Venues Services, Access Grid Nodes, and Access Grid Network Services. The Venues Services provide navigation, discovery and security for resources. Access Grid Nodes are spaces that are designed to provide comfortable, high fidelity, natural interactions with Access Grid resources. Access Grid Network Services provide capabilities such as venue recording, stream processing, and bridging between the Access Grid and other collaboration systems. Applications can use this infrastructure to provide groups with the ability to share data, computing resources, and applications among widely distributed participants.
The target use of the Access Grid involves 6-8 nodes that have 3-10 participants per node. The intent of the Access Grid is to enable groups of collaborators to increase productivity by reducing the work involved in finding expert resources, people, publications, source code, data and computing resources. The Access Grid is also used for classroom lectures, training, invited talks, and collaborative activities such as strategy and management meetings.
Inevitably, collaborations involve participants that are not co-located with other participants. These users need to be able to interact with the Access Grid as fully as their technology permits them. Users that do not have a space that meets the minimum requirements, but need to participate in AG based collaborations can do so at a reduced level of functionality. Participants without nodes connect to the AG venues through AG network services. AG network services resolve the mismatch in capabilities between the participants? environment and the rest of the AG. AG network services that might be utilized to bring participants into the collaboration include transcoding, subsampling and mixing services. The same AG network services that allow users with reduced capabilities, also provide the same services for users with extra capabilities.