Software design generally employs different techniques in different phases for analysis. In the beginning, a new network protocol may be conceptualized and tested in a network simulator. Later on, a prototype of the actual implementation is thoroughly analyzed. Both approaches have their specific up- and downsides. Network emulation allows to combine both to gather additional data and facilitate easier prototype testbed layouts. For meaningful analysis however, especially in regard to timing behavior, the simulation has to be real-time capable. This is often not the case for complex simulated scenarios. This diploma thesis designs and implements a synchronization that allows to run any x86 operating system with arbitrarily complex simulations. By encapsulating the OS in the Xen hypervisor, it relieves the simulation from the real-time capability constraint while still maintaining realistic timing behavior.