NCTUns distributed network emulator

Emulation enables real-world devices to interact with a network simulated in real time. It is a very useful approach to testing the functions and performances of real-world devices under various simulated network conditions. To conduct a network emulation, the clock of the network emulator needs to be accurately synchronized with the real-world clock. However, when the load of the network emulator is too high, which slows down the advances of its clock, accurately synchronizing its clock with the real-world clock becomes impossible. To overcome this problem, in this paper we purpose a distributed network emulation approach. This approach partitions a large network into several smaller parts and let each part be emulated by a different machine. We have applied it to the NCTUns network simulator and emulator and developed a highly-integrated NCTUns distributed emulation environment. On this environment, one can easily set up, conduct, and control a multi-machine distributed emulation on a single NCTUns machine. In this paper, we present the design of this approach, introduce the operations of the NCTUns distributed emulation environment, and evaluate its emulation performances. 1