SCRIBE: The Design of a Large-Scale Event Notification Infrastructure

In this paper we outline the design of Scribe, a reliable large-scale event notification infrastructure, built on top of a peer-to-peer object location and routing infrastructure overlayed on the Internet (Pastry). Scribe provides large-scale distributed applications with a highly flexible group communication protocol. Scribe leverages Pastry [1] and benefits from its robustness, reliability, self-organization and locality properties. The peer-to-peer model of Pastry is very well suited to a scalable implementation of group communication. The Pastry routing scheme is used to create a group (a topic) and to build an efficient multicast tree for the dissemination of events within groups composed of a potentially large set of members (subscribers). Scribe is highly scalable and can support potentially billions of topics and subscribers per topic and multiple publishers per topic. Scribe relies on an efficient tree control mechanism, which reconfigures the multicast tree to track changes in group membership and use.