Hauck, Franz J. ;
Geier, Martin
:
Fragmented Objects for the Implementation of Mobile Agents.
Erlangen:
FAU.
2000
TR-I4-00-05.- Interner Bericht.
14 Seiten.
Abstract:
Mobile agents are a promising approach to distributed software.
The typical programming paradigm considers a mobile agent to be a mobile object or a group of
objects migrating together. Important issues of this approach are abstraction, encapsulation,
a well-defined interface, and the clear definition of a migration entity. Putting the whole
functionality of an agent into one migration entity is not feasible for real world applications
because one important benefit of a mobile agent, namely the efficient communication at the destination
site, does not compensate migration costs. FOMAS, a fragmented object model for mobile agents,
offers a solution to this problem. Agents are split into smaller and mobile fragments,
which still belong to the same object and agent respectively. Agents can scale with respect to mobility
as also just parts of the agent can migrate. Agents can have replicated components and have multiple points
of presence. The design of a fragmented agent is a crucial point, as the defragmentation has to be done for
mobility and distribution reasons. We present the approach of phase-oriented agents (POMAS) as a design method
for fragmented agents where agents are split into time-bounded sub-tasks. A mathematical model provides the
break-even point at which the phase-oriented approach outplays the monolithic agent approach. These results
are confirmed by a prototypical implementation.
