Mobile Agent on Voyager Agent System Platform

The configuration of the browser on a host is carried out by a mobile agent, which moves to several hosts, where the configuration task is executed. The mobile agent of the prototype implementation executes the following steps on every host:

1.

initialization

2.

execution of task

3.

computation of the remaining route

4.

migration to the next host

For the implementation of the mobile agent the Voyager agent system platform is used [#!Voy2000!#]. The heart of the Voyager agent system platform is the class Agent, which can convert any serializable object into an object of the type IAgent. An object of type IAgent offers the method moveTo(), which realizes the movement of an object to a remote host. moveTo() takes as parameters the destination address of the remote host and optionally the specification of a method provided by the moving object. After the movement of the object all local references to the object can be released, though the object is not deleted on the remote host. It can act autonomously.

For the sample application an instance of the class WebClientAgent is converted to an object of the type IAgent. The method moveTo() is called, specifying the destination address of the first host and the method run() as the starting point of the execution on the remote host. The method run() triggers the browser configuration and invokes after the execution of the task the method moveTo() again specifying the next host and itself as execution point (s. figure ).

 

Figure: Movement of WebClientAgent object  

The movement and the execution of the configuration of the web browsers continues until all hosts listed for configuration are visited. Then the object dies.

The condition for moving an object to a remote host when using Voyager is a running Voyager server on the remote host. A Voyager server is a separate Java program which listens for requests on a specified port and provides the runtime environment for the received object. The specified port builds together with the host name of the remote host the destination address. The destination address is used as a parameter for the method moveTo().