From H-A P/S Wiki

This is a home page for the Handling Overload in Publish/Subscribe Systems project. The main assumption of the H-O P/S project is to create a subscription system based on the analysis of the content of sent messages which would work effectively in dynamic Wide-Area Networks. This project is supported by the Polish Ministry of Science and Higher Education grant number N N516 375034.

What is the project goal?

The present knowledge on Publish/Subscribe Networks is still incomplete and is an object of intensive research in the scientific environment. One of the main problems is a lack of a complex solution to the problem of routing - the existing solutions do not allow using subscription networks on a broad scale. One of the reasons of this status quo are large computational overheads during matching publication and subscription information. Another problem is a lack of complex research into the behaviour of the subscription networks in the conditions of overloads and damages of network lines and nodes. One ought to note that these problems are especially interesting due to the introduced communication model: a peer-to-peer model maintaining asynchronism and anonymity. Its effect is a lack of possibility of trivial adaptation of the already known solutions.

The main assumption of the H-O P/S project is to create a subscription system based on the analysis of the content of sent messages which would work effectively in dynamic Wide-Area Networks. The above foundation will be realized as a result of the execution of the following research:

1. Determining an efficient routing algorithm which would allow scaling the system together with an increase in the number of its users
2. Finding a solution to the problem of routing at the overload of the lines between individual network nodes as well as the overload of the network node itself so that the cost function will reach the minimum while maintaining the conditions determining the subscription network. It is a matter of fact that in case of the overload networks it is impossible to deliver services of the assumed quality to all customers of the subscription network, yet on the other hand, due to the asynchronous nature of the Publish/Subscribe Networks, it is not possible to reserve a line a priori since it leads to violation of the assumptions of the subscription systems.
3. Extension of the Publish/Subscribe solutions by mechanisms allowing one to determine the time of message routing and by mechanisms allowing one to determine the completeness of the received information. The existing systems allow one to ensure an order of the sent information, but either they do not realize the transfer in the subscription networks, or they base their activity on synchronization with the use of the NTP protocol.

Three approaches - analytic, simulation and experimental - will be applied to the research into the Public/Subscribe systems in Wide-Area Networks and Wide-Area Telecommunication Networks. Patterns and algorithms used for routing and making decisions in the network nodes will be determined analytically, then they will be tested in the OMNeT++ simulation environment and next they will be implemented and verified through experiments in the PlanetLab global network. The applied methodology of research will allow numerical and experimental determining the efficiency of the activity of the prepared algorithms. The detailed task list is as follows:

• creating a model of subscription networks for the OMNeT++ simulator
• creating a generator of topology and traffic for the subscription networks
• creating and implementing the routing algorithms
• simulation investigation of algorithms based on the created environment
• simulation investigation of behaviours of networks in the conditions of overload
• creating overload control algorithms
• creating message loss detection algorithms
• implementing the system in the PlanetLab and Emulab environment

Recommended Reading

If you like the idea, a recommended survey paper for the Publish/Subscribe systems and terminology would be: Patrick Th. Eugster and Pascal A. Felber and Rachid Guerraoui and Anne-Marie Kermarrec, The many faces of publish/subscribe, ACM Comput. Surv., Vol: 35, 2003, pp. 114--131 . DOI: [1]

Who stands behind?

If you want to know more about us take a look at the People page. Beside that, you might want to know, that we are supported by: Silesian University of Technology, Polish Ministry of Science and Higher Education.