Network emulation is an efficient method for evaluating distributed applications and communication protocols by combining the benefits of real world experiments and network simulation. The process of network emulation involves execution of thousands of connected virtual nodes running the software under test in a controlled environment. Along with the quality of the experiment results, the runtime of network experiments strongly influences the convenience of users and operators of emulation testbeds. The goal of this paper is, therefore, to minimize the experiment runtime of network emulations.

In order to achieve this goal, we make the following contributions in this paper: First, we present a highly scalable emulation architecture to efficiently support network emulation testbeds with multicore CPUs. Second, we propose a detailed and generic cost model for the communication costs of emulation testbeds. Third, we present an efficient placement strategy (NETplace) to assign virtual nodes to physical nodes of the testbed while minimizing the runtime of network experiments. Therefore, we combine graph partitioning and greedy approaches. Our evaluations show that our placement strategy outperforms existing methods by reducing the experiment runtime up to 64%.