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The Monitoring Package

The monitoring package is composed of four other sub-packages. The first is responsible for the interception of the interactions between the objects that comprise the applications in the distributed system. Our intention is to follow the model described in [7]. In this work, Interceptors, as defined in the CORBA standard [10], are inserted into the object invocation path. Each time a client invokes a method of an object, the message corresponding to this invocation is intercepted and later re-dispatched to the target object. Using interceptors, the system can extract useful information from each method invocation, storing it in a log for later analysis by the event evaluator package. Furthermore, each request can be time-stamped so that one can know when a message invocation request was received at the server side. The system can also measure the time between the reception of the message at the server and the dispatching of the response to the client, which corresponds to the duration of the method execution at the server. In addition to monitoring object interactions, it is also important to monitor the status of distributed resources, such as memory, CPU, disk, and network connectivity. This is performed by the resource monitoring package. To implement such monitoring functionality we propose the use of resource monitoring objects, responsible for monitoring system specific parameters, such as processor utilization, in different hosts of the distributed system. The resource monitoring package notifies the event evaluator package whenever the operation of such parameters changes significantly. Yet another interesting aspect related to monitoring is the location of mobile devices. As described in the Introduction, we believe that location awareness will play a fundamental role in future distributed computing environments. We assume that soon most mobile devices will be equipped with sensors that will allow us to obtain information about their physical location. Finally, since we are working in a mobile environment, the services and resources that a user will be able to use vary depending on his(her) location. So, the monitoring package should also include the functionality for dynamically discovering resources and services as the user moves from one place to another, this is performed by the Resource and Service Discovery package. Currently, we are concentrating our efforts in the design and implementation of the first two packages of this monitoring infrastructure.
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Next: Event Detection and Notification Up: Goal Statement Previous: Goal Statement
Francisco Jose da Silva e Silva 2001-09-24