A potential application of the mobile agent paradigm is the scenario of distributed information retrieval, where a small subset of data must be selected from a big superset of data distributed over a set of hosts. In all traditional client-server architecture the whole superset must be moved over the network to the computational component, that executes the selection. When deploying mobile agents the computation is executed close to the information base, which avoids the communication over the network for the selection. The mobile agent transports over the network only the small subset of data selected out of the information base.
A wide spread form of mobile code is the enhancement of electronic documents for interactivity and presentation effects, like web pages or e-mail. It enables the local execution of programs that are associated with the document. For instance, user inputs can be locally evaluated and improve the interactivity of the document. The usual paradigm used for this scenario is code on demand . E.g. WWW technologies and Java applets offer the necessary mechanism for active documents.
Another scenario which is interesting for the deployment of mobile code is the remote control of devices, e.g. network management. Especially the monitoring where the status of devices are checked by continuous polling may generate considerable network traffic and may cause other problems in a traditional client-server architecture. The alternative is to move the monitoring functionality to the devices and to fire events reporting about the state of the devices.
In the area of work flow management systems activities can be mapped on mobile components. The mobile components circulate through all participating entities which are involved in the work flow. The mobile components which encapsulate documents can control access rights to the document and the revision status of the document.
Active networks may be considered as another application of mobile code [#!TenSmi1997!#]. It is used to manage the network through the traffic itself. There exist basically two approaches: the programmable switch and the capsule. The programmable switch conforms with the code on demand approach, where the node loads executable code for extended functionality. The capsule approach embeds the executable code into the packets. The embedded code is executed at every node which is passed by the packet.
In the scope of electronic commerce mobile code helps to customize the behavior of participating parties by encapsulation of protocols. It also supports moving mobile agents in order to operate close to the information base or to other mobile agents participating at the negotiations, e.g. in a virtual marketplace.