MEDYM: An Architecture for Content-based Publish-Subscribe Service Networks

Abstract:

Designing a distributed architecture for content-based
publish-subscribe service networks is challenging for two reasons: first,
communication in such system is guided by the content of publications and
subscriptions rather than addresses or network locations; second, while a
publication often matches subscriptions from multiple locations, existing
group-based multicast techniques such as IP multicast or application-layer
multicast are not readily applicable due to the highly diversified
patterns of interests. We propose an architectural approach that combines
two orthogonal aspects: Match Early, and DYnamic Multicast. We call this a
MEDYM architecture, and we compare it with two major existing design
approaches: Content-based Forwarding and Channelization. In MEDYM, event
publications are matched as close as possible to publishers, to obtain the
locations of servers that have matching subscriptions; then, a multicast
route to the matching servers is computed dynamically, to best suit the
heterogeneous event traffic patterns. We present methods to efficiently
implement the dynamic multicast routing. We evaluate the MEDYM
architecture using detailed simulations as well as a prototype deployment
on the PlanetLab test bed. Experimental results show that the MEDYM
approach significantly improves storage, computation and network
efficiency compared to existing approaches, and is resilient, scalable,
and extensible.