In this work, EmuStack, a network emulation platform for DTN, is introduced. With the advancement of network and compute virtualization technology, it becomes much easier to design and implement a scalable and flexible emulation platform than before. Meanwhile, without using network virtualization technology, the emulation topology of SPICE is fixed and will be changed difficultly.
However, due to the introduction of professional hardware, SPICE is hard to be imitated by other researchers. SPICE is equipped with special hardware and it can accurately emulate the link characteristics between the space and ground stations. Komnios introduces the SPICE testbed for researching space and satellite communication. Thus, QOMB lacks a monitoring system the experimental fidelity cannot be guaranteed especially in the large-scale scene. QOMB has a good support for emulating a large-scale mobile networks, but it wastes lots of hardware resources since none of virtual computing technology is employed. Based on the generic-purpose wireless network bench, Beuran designs a testbed named QOMB. The DTN testbed can support about ten nodes experimental topology. Koutsogiannis implements a testbed to evaluate space-suitable DTN architectures and protocols with many deep space communication scenarios. In order to further study DTN architecture, many experimental platforms have been designed. However, many problems such as security and contact plan design have not been resolved yet. In DTN areas, related research works such as routing and congestion control strategies have obtained many achievements along with a number of DTN implementations such as DTN2, ION, and IBRDTN. DTN was initially invented for the deep space communication, while currently it has been gradually applied in wireless sensor networks, ad hoc networks, and even satellite networks. The key idea of DTN is custody transfer which adopts the hop-by-hop reliable delivery to guarantee the end-to-end reliability.
In particular, in order to adapt Internet to these challenging environments, Fall proposes Delay Tolerant Networks (DTN). Excited enough, there have been increasing efforts to support these challenging networks on some special delay and interrupt scenes. However, many challenging networks (such as sensor/actuator networks and ad hoc networks) cannot satisfy one or more of those assumptions. The current Internet is based on a number of key assumptions on communication system, including a long-term and stable end-to-end path, small packet loss probability, and short round-trip time. EmuStack environment would bring qualitative change in network research works. Finally, experiences with our initial implementation suggest the ability to run and debug experimental network protocol in real time. In addition, EmuStack integrates the Linux Traffic Control (TC) tools with OpenStack for managing and emulating the virtual link characteristics which include variable bandwidth, delay, loss, jitter, reordering, and duplication. Meanwhile, the lightweight approach of using Docker container technology and network namespaces allows EmuStack to support a (up to hundreds of nodes) large-scale topology with only several physical nodes. Based on OpenStack, distributed synchronous emulation modules are developed to enable EmuStack to implement synchronous and dynamic, precise, and real-time network emulation. EmuStack aims at empowering network emulation to become as simple as network simulation. In this paper, EmuStack, a large-scale real-time emulation platform for Delay Tolerant Network (DTN), is proposed. Compared with network simulation, network emulation can provide more relevant and comprehensive details. With the advancement of computing and network virtualization technology, the networking research community shows great interest in network emulation.