Achieving Scalability and Expressiveness in an Internet-Scale Event Notification
Service
Antonio Carzaniga, David S. Rosenblum, Alexander L. Wolf
To appear at Nineteenth Annual
ACM SIGACT-SIGOPS Symposium on PRINCIPLES OF DISTRIBUTED COMPUTING (PODC
2000), Portland, Oregon, 16-19 July 2000
Abstract
This paper describes the design of Siena, an Internet-scale event notification
middleware for distributed event-based 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.