A main challenge in distributed publish/subscribe systems is the efficient
and scalable routing of incoming information (event messages). For largescale
publish/subscribe services, subscription forwarding has been established as
a prevalent routing scheme. It reduces the network traffic for event routing due
to selectively forwarding event messages to relevant parts of the network only.
To further improve event routing, publish/subscribe systems apply routing optimizations.
So far, optimizations for general-purpose publish/subscribe systems
are still missing.
In this paper, we present the architecture, realization, and evaluation of our prototype
of a large-scale publish/subscribe service applying a novel routing optimization,
subscription tree pruning. We also show a comparison of five existing
routing optimizations in respect to six important characteristic parameters affecting
the suitability of these approaches in practice (including space usage, time
efficiency (throughput), and network load). This comparative analysis clearly
demonstrates the advantages of subscription pruning over other routing optimizations.
In our practical experiments, we then investigate the behavior of our prototype
regarding all quantitatively measurable parameters from our previously
theoretically analyzed ones. Our evaluation of subscription pruning in this paper
is more extensive than previous analyses of any routing optimizations for publish/
subscribe systems, which focus on selected parameters only.
