mcast-IBM-RR - An Efficient Multicast Protocol for...

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Abstract. The publish/subscribe (or pub/sub) paradigm is a simple and easy to use model for interconnecting applications in a distributed environment. Many existing pub/sub systems are based on pre-defined subjects, and hence are able to exploit multicast technologies to provide scalability and availability. An emerging alternative to subject-based systems, known as content-based systems, allow information consumers to request events based on the content of published messages. This model is considerably more flexible than subject-based pub/sub, however it was previously not known how to efficiently multicast published messages to interested content-based subscribers within a network of broker (or router) machines. This shortcoming limits the applicability of content-based pub/sub in large or geographically distributed settings. In this paper, we develop and evaluate a novel and efficient technique for multicasting within a network of brokers in a content-based subscription system, thereby showing that content-based pub/sub can be deployed in large or geographically distributed settings. 1 Introduction The publish/subscribe paradigm is a simple, easy to use and efficient to implement paradigm for interconnecting applications in a distributed environment. Pub/sub based middleware is currently being applied for application integration in many domains including financial, process automation, transportation, and mergers and acquisitions. Pub/sub systems contain information providers, who publish events to the system, and information consumers, who subscribe to particular categories of events within the system. The system ensures the timely delivery of published events to all interested subscribers. A pub/sub system also typically contains message brokers that are responsible for routing messages between publishers and subscribers. The earliest pub/sub systems were subject-based . In these systems, each unit of information (which we will call an event ) is classified as belonging to one of a fixed set of subjects (also known as groups, channels, or topics). Publishers are required to label each event with a subject; consumers subscribe to all the events within a particular subject. For example a subject-based pub/sub system for stock trading may define a group for each stock issue; publishers may post information to the appropriate group, and subscribers may subscribe to information regarding any issue. In the past decade, systems supporting this paradigm have matured significantly resulting in several academic and industrial strength solutions [4][10][12][13][15]. A similar approach has been adopted by the OMG for CORBA event channels [11]. An emerging alternative to subject-based systems is content-based subscription systems [6][14]. These systems support a number of information spaces , each associated with an event schema defining the type of information contained in each event. Our stock trade example (shown in Figure 1) may be defined as a single information space
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This note was uploaded on 12/08/2011 for the course CS 525 taught by Professor Gupta during the Spring '08 term at University of Illinois, Urbana Champaign.

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mcast-IBM-RR - An Efficient Multicast Protocol for...

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