Scenarios

The deployment of mobile code in the area of network management is a promising approach [#!FerKasKra1999!#], [#!GscFerPle1999!#],[#!BiPaWh1998!#], [#!MinHulMae1998!#]. As described at the beginning of the chapter, today's computer networks are heterogeneous and thus network management has to deal with managing heterogeneous devices. Even when using platform-independent technologies, e.g. Java, the device properties can differ so strongly that it is necessary to apply implementations which are tailored for specific classes of devices only and packed altogether to support a broad spectrum of environments. For instance, the configuration of network elements by Java technology affords to deal with a variety of device sizes apart from producer specific interfaces. Enhanced PC's serving as routers offer the full functionality as provided by a standard JVM, in contrast to specific router devices which do not offer the execution of Java programs. Though small ipEngines [#!Br1998!#] support common operating systems and the execution of Java programs in a JVM, the available resources in terms of memory are very limited and special version of Java programs are necessary.

Another common scenario can be found in the world of Java applets. Different configurations of browsers, which provide the JVM for the applet, support different Java versions and different set of pre-installed Java packages. This leads to incompatible Java applets, if the user does not interact and add necessary Java packages, e.g. Swing packages. The instrumentation of an applet with all necessary packages, which could miss for the execution, is undesirable because of long loading times and inefficient usage of bandwidth. Dynamic adaptation offers an alternative by small applets which can be loaded and executed by every browser, and triggers the loading of additional packages or classes if needed. For example, if swing packages are missing it can switch to a GUI based on the traditional Java AWT.

A third scenario which also belongs to the field of network management, deals with the configuration of applications by mobile code. A set of applications is installed on hosts using different operating systems and cpu architectures. The configuration of the application depends on the system parameters of the host. In a mobile code architecture which does not rely on adaptation, it is either necessary to know the exact hard- and software configuration of every host, which affords complex administration and maintenance, or code for all possible configuration is packed together and sent to the hosts, which means long latency and network traffic that could be avoided. The configuration of a network browser which is selected as the application example for such a scenario for illustration purposes in this work. It is also taken as example application of the prototype implementation, which will be described in chapter .