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Handbook on Mobile and Ubiquitous Computing: Status and Perspective
emulator offers the physical resources available and the network emulator in combination with
Xen is the operating system and communication facility. Since the host operating system is Linux,
applications can be written in any number of programming languages. The core operating system
is implemented in C and C++, which means that most lower layer codes like routing daemons
are also written in C and C++. To enable cross-layer design, code running in different layers
must be able to communicate with each other. Usually, this is done via direct API calls, vir-
tual devices, or even shared memory. This approach requires that development of code in the
cross-coupled layers must be