Projects
From H-A P/S Wiki
This page gives a brief overview of the sub-projects of the H-A P/S project. For more information on each sub-project follow the provided links or take a look at the publications.
Fail-Aware Publish/Subscribe (F-A P/S)
This project aims to bridge the gap between the asynchronous communication scheme represented by the Publish/Subscribe and the Fail-Awareness. The resulting work will introduce the ability to calculate an upper bound on the event delivery delay in the Pub/Sub systems. The so obtained value would present an invaluable aid in many cases, whenever the timely delivery of messages in an asynchronous system would be desirable.
Value Based Routing
This project focuses on the issues of high availability of distributed systems using Pub/Sub. We have developed mechanism that allow for graceful handling of computational limitations of the network routers and potential link failures when low bandwidth links are used for backup. We have developed a novel scheme for coping with the problem of load shedding. We use a value-based approach where users of the system assign values to the subscription messages and hence allow for intelligent prioritizing of the messages in the Pub/Sub routers. This approach allows us to maintain the delivery of the globally most valuable information when system suffers the overload condition.
Furthermore we work on extending the already existing solution with the notion of Fail-Awareness. Fail-Awareness allows systems to detect when they cannot guarantee all their safety properties and in particular, to detect when to switch to a fail-safe mode. Our implementation of Fail-Aware Publish/Subscribe system will allow for the computation of the deterministic end-to-end upper bound on the message transmission delay in fully decoupled, asynchronous (no clock synchronisation, bounded drift rate) systems.
Value Based Routing - Publications
- Zbigniew Jerzak and Christof Fetzer, Handling Overload in Publish/Subscribe Systems (PDF ~370KB). Proceedings of the 6th DEBS Workshop, Lisbon, Portugal, July 2006.
- Zbigniew Jerzak, Highly Available Publish/Subscribe (PDF ~200KB), In Supplement Proceedings of the High Assurance Systems Engineering Conference, pp. 11--12, Heidelberg, Germany. October, 2005
