Extending Content-based Publish/Subscribe Systems with Multicast Support

Event-based interaction is recognized as being well suited for loosely coupled distributed applications. Current distributed content-based event notifications services are often architectured to operate over WANs (wide area networks). Additionally, one to one transport layer communication primitives are used. As a result, these services are not suitable for (parts of) applications having a combination of high event notification rates and locally a large number of interested parties for the same event notifications. In this paper we describe the architecture of a distributed content-based event notification service, designed to take advantage of the available performance and native multicast support provided by current “off the shelf” network equipment. Our event notification service is designed primarily as a LAN (local area network) service and hence complementary to event notification services for WANs. A prototype has been implemented and experiments indicate that our service provides both scalability and high performance. A client may publish several thousand event notifications, carrying several MBytes of data, per second. The service is unaffected by the number of interested parties, due to the use of native multicast.