The iServer platform supports the integration of cross-media resources based on the resource-selector-link (RSL) model. iServer not only enables the definition links between different types of digital media, but can also be used for integrating physical and digital resources.
The RSL model introduces the abstract concepts of resources, selectors and links and can be extended for specific types of resources (e.g. interactive paper, HTML pages or movie clips). By implementing media-specific resource and selector instances, any new type of media can be integrated. The framework has been used within the European Paper++ and PaperWorks projects for integrating physical paper and digital content and is the main component of our interactive paper infrastructure. Further, we are developing plug-ins for XHTML documents, movie clips and sound files. The sharing of link knowledge has been investigated in a distributed iServer version based on peer-to-peer concepts.