Federation transparency in ODP Trading function

Lea Kutvonen: Federation transparency in ODP Trading function. Report C-1994-32, Department of Computer Science, University of Helsinki, May 1994. 12 pages. <http://www.cs.helsinki.fi/TR/C-1994/32>

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Abstract

Trading is a central infrastructure function specified within ODP (Open Distributed Processing) reference model, which is in progress within ISO and ITU standardization organizations. The goal of the ODP framework is to provide a distribution transparent environment for software components to interwork, despite they are supported by heterogeneous platforms. Software components (and hardware, as well) are modeled as objects. Objects request services from their environment, i. e. from other objects. Distribution transparency requires transparency of failures, locations and implementation technologies of services. To achieve location transparency within the infrastructure, ODP framework introduces a trading function. Traders provide to their clients a network wide selection among interchangeable service provider objects. The selection is based on object properties. Static properties describe the abilities of an object, dynamic properties the status of an object. The trader selects a server object for a given task by considering the dynamic status of service providers, service requestors and the underlying system infrastructure. As the global network is composed of several autonomous, heterogeneous subsystems, an implementation of trading functionality can not be centralized. Each autonomous subsystem should have a trader administering services. To achieve location transparency throughout the combined network, traders have to cooperate. This cooperation is called federation. An important goal is that the objects using trading function, should not be forced to see administrative boundaries between subsystems. Instead, trading should happen in a federation transparent way. This paper introduces a method to achieve federation transparency in a heterogeneous environment.

Index Terms

Categories and Subject Descriptors:
C.2.4 [Computer Communication Networks]: Distributed Systems

General Terms: Distributed systems, heterogeneous systems

Additional Key Words and Phrases: Trading function, federation transparency