Event-Based Integration has been championed as an ideal coordination
technique for loosely-coupled systems. Over the last two decades, event
notification services have evolved within hosts (as kernel, graphical
user interface, operating system, and object-oriented runtime events),
within local area networks (as tool integration, remote procedure call,
networked windowing system, and distributed file system lease events),
and within wide area networks (as telepresence, interactive simulation,
network management, and workflow events). Emerging generations of these
collaborative applications now need to span organizational boundaries -
and require event notification mechanisms that scale to the Internet.
This implies more than adapting to wide area networks' space and time
scales: successful Internet-scale services will have to be evolvable,
decentralized, secure, and reliable within an imperfect network.