Kooperative multimediale Anwendungen: Basis für virtuelle Arbeitsumgebungen

The article starts describing synchronous, document-based groupware applications as an important basis for virtual workspaces and internet-wide distributed collaborating teams working in areas such as media design, engineering and electronic banking. New communicative and collaborative software solutions are preconditions for such scenarios. The article points out deficits of existing application sharing technology used for collaboration, suggests supplementing this technology by synchronous documentbased groupware applications and lists requirements for these applications. It is described how general support for replication, synchronisation and concurrency control a development framework should provide. Furthermore the article discusses, how the parts of an interactive application should be distributed by using the MVC paradigm. An approach based on replication that combines message passing and state passing for synchronisation and a distributed optimistic concurrency control with rollback-able short transactions are outlined. For handling resulting differences in application development, an advanced observer pattem is proposed

The PERMIS X.509 Based Privilege Management Infrastructure

This document describes the PERMIS X.509 Based Privilege Management Infrastructure, which is a trust management system as described in RFC 2704 [2]. The PERMIS Infrastructure is compared with the AAA Authorisation Framework described in RFC 2904 [4], and is shown to be compatible with it

Unicast UDP Usage Guidelines for Application Designers

Publisher PD

Securing the RTP framework: why RTP does not mandate a single media security solution

This memo discusses the problem of securing real-time multimedia sessions, and explains why the Real-time Transport Protocol (RTP), and the associated RTP control protocol (RTCP), do not mandate a single media security mechanism. Guidelines for designers and reviewers of future RTP extensions are provided, to ensure that appropriate security mechanisms are mandated, and that any such mechanisms are specified in a manner that conforms with the RTP architecture

Developing a Framework to Implement Public Key Infrastructure Enabled Security in XML Documents

This paper concentrates on proposing a framework to implement the PKI enables security in XML documents, by defining a common framework and processing rules that can be shared across applications using common tools, avoiding the need for extensive customization of applications to add security. The Framework reuses the concepts, algorithms and core technologies of legacy security systems while introducing changes necessary to support extensible integration with XML. This allows interoperability with a wide range of existing infrastructures and across deployments. Currently no strict security models and mechanisms are available that can provide specification and enforcement of security policies for XML documents. Such models are crucial in order to facilitate a secure dissemination of XML documents, containing information of different sensitivity levels, among (possibly large) user communities