Achieving scalability and expressiveness in an Internet-scale event notification service

Abstract

This paper describes the design of SIENA, an Internet-scale event notification middleware service for distributed eventbased applications deployed over wide-area networks. SIENA is responsible for selecting the notifications that are of interest to clients (as expressed in client subscriptions) and then delivering those notifications to the clients via access points. The key design challenge for SIENA is maximizing expressiveness in the selection mechanism without sacrificing scalability of the delivery mechanism. This paper focuses on those aspects of the design of SIENA that fundamentally impact scalability and expressiveness. In particular, we describe SIENA'S data model for notifications, the covering relations that formally define the semantics of the data model, the distributed architectures we have studied for SIENA'S implementation, and the processing strategies we developed to exploit the covering relations for optimizing the routing of notifications.

Coordination Via Types in an Event-Based Framework

“…C initiates authentication by presenting a User-Supplied Identifier to the SP via its User-Agent. 4. SP establishes an Endpoint URL used by C for authentication.…”

“…In content-based EN, component decoupling is enforced by allowing subscribers to register for events satisfying a given property. When an event is emitted the middleware has to dispatch it to all the subscribers whose property holds on that event (an example of content-based is SIENA [4]). Notoriously, content-based dispatching mechanisms must be efficient because notification sets, i.e.…”

Model Checking Publish-Subscribe Systems

“…Publish-subscribe systems have received considerable attention in commercial products and standards (e.g., [20,18]), as well as academic research systems (e.g., [4,19]). Most of these efforts have focused on the problem of constructing systems that exhibit desirable run time qualities, such as scalability, efficiency, adaptability, and security, rather than the problem of reasoning about the correctness of such systems, as in this paper.…”

The Architecture of the Cornell Knowledge Broker

“…It is functionally similar to a continuous data stream query processor [5,7,12,15,16], a publish/subscribe system [25], or an event processing system [3,13,14,38,44]. However, there are significant differences.…”