Test and evaluation of wide area networks using emulator cluster

Network emulation offers real-time simulation that enables test and evaluation of real network systems, protocols, and applications in a reconfigurable and controllable hardware and software environment. Real network traffic is processed by the protocol stacks of physical systems across the entire emulation environment. Standalone emulators can only be used to test end-to-end protocols and applications; simple emulator testbeds are non-scalable due to the one-to-one mapping scheme. We present a distributed emulator cluster that can faithfully emulate large-scale wide area networks with only a considerably smaller number of workstations. In the emulator cluster, a network topology is accurately mapped to a virtual topology in which certain number of virtual nodes are properly configured and emulated. We have developed an algorithm to partition a target network such that each partition can be emulated by a physical node. The emulator cluster can emulate a variety of network conditions and traffic dynamics, as well as incorporating new protocols and models. Preliminary test results show the high scalability of emulator cluster in terms of emulation validity and accuracy with a single physical node and in the entire environment.