Evolution of ISENS: Past, Present, Future.

I Find Karma (adam@cs.caltech.edu)
Mon, 20 Jul 1998 14:56:57 -0700

The Evolution of Internet-Scale Event Notification Services:
Past, Present, and Future
by Adam Rifkin and Rohit Khare


Speculative Paper Submission for the International Joint Conference on
Work Activities Coordination and Collaboration (WACC '99)


Aside from the occasional symphony orchestra or barn-raising, few human
work activities proceed in strict temporal or command sequence.
Collaborative processes are loosely-coupled by nature -- especially with
humans in the loop -- and thus well-suited to event-based implicit
invocation. We have identified over eighty such event-oriented
collaborative tools that emerged over the last two decades. This paper
aims towards an evolutionary explanation of the popularity of this
approach, its current challenges, and likely next steps.

single hosts to local-area networks to wide-area networks -- within each
of five application themes: information distribution,
presence/awareness, instant messaging/chat, simulation/graphics, and
interapplication integration. Academic literature in the area can be
reinterpreted to separate applications using Event Based Integration
(EBI) from underlying Event Notification Services (ENS).

The present moment is less about adapting to ever-wider geographic,
temporal, and numeric scale, than the trust boundaries uniquely defining
"Internet scale." New tensions are surfacing in bridging dissimilar
ontology, security, and mobility models. Furthermore, the politics and
economics of Internet scale are dominated by the "network effect," the
tendency for a common, interoperable standard to become more valuable
precisely in proportion to the numbers of developers and applications
using it.

The future appears to favor generic Internet scale ENS, with built-in
evolvability features to expand and adapt to new collaborative systems'
demands. We propose a taxonomy of ENS design choices -- source- vs.
sink-initiation; end-to-end vs. intermediated delivery; degree of
latency; and ordering constraints -- to evaluate contenders' claims of


Contact information:

Adam Rifkin, California Institute of Technology, adam@cs.caltech.edu,
phone: +1-626-449-4123, fax: +1-626-792-4257

Rohit Khare, University of California at Irvine, rohit@uci.edu, phone:


The theory of evolution was greatly objected to because it made man think.