Optical Burst Switching (OBS) is the future of optical internet which provides a promising architecture to efficiently utilize WDM and to fulfill today’s Internet traffic demands. Since this area is yet to mature there is a darn need to study its various protocols. Network simulator is an important tool for researchers and academicians to simulate and model the actual network at a reduced cost compared to the real test-bed experimentation. In this paper various OBS simulators are comparatively surveyed, while highlighting their merits and demerits.

In object oriented distributed systems (OODS), the objects are viewed as resources. Concurrency control techniques are usually applied on the database tier. This has the limitations of lack of support of legacy files and requirement of separate concurrency control mechanisms for each database model. Hence concurrency control on the objects at server tier is explored. To implement concurrency control on the objects participating in a system, the impact of method types, properties and class relationships namely inheritance, association and aggregation are to be analyzed. In this paper, the types and properties of classes and attributes are analysed. The semantics of the class relationships are analysed to ascertain their lock modes, granule sizes for defining concurrency control in OODS. It is also intended to propose compatibility matrix among all these object relationships.