Sebastian Schildt

IBR-DTN: A lightweight, modular and highly portable Bundle Protocol implementation

In this paper we present IBR-DTN, a lightweight, modular and portable Bundle Protocol implementation and DTN daemon. IBR-DTN is especially suited for embedded platforms, which allows to leverage the benefits of a fully compliant Bundle Protocol daemon in cost sensitive distributed sensing applications. We line out IBR-DTNs extensible software architecture and introduce the modules included in the standard IBR-DTN distribution. To give an impression of the performance that can be expected when using IBR-DTN, we perform a series of benchmarks and compare the outcome with DTN2 performance, the reference implementation of the Bundle Protocol.

DroidCluster: Towards Smartphone Cluster Computing -- The Streets are Paved with Potential Computer Clusters

What is the processing-power of an omnibus? Can a train compute a climate model? Todays smart phones are becoming more and more powerful and have a performance similar to former high-end workstations. This power can also be used in a joint and cooperative way by building local and mobile ad-hoc clusters. In this paper we will show that setting up a smart phone cluster is not only possible, but it is also a reasonable thing to do, considering the sheer amount of mobile devices and the applications that could benefit from it.

Detecting blackhole and greyhole attacks in vehicular Delay Tolerant Networks

Blackhole and greyhole attacks can cause severe problems in Delay- and Disruption-Tolerant Networks (DTNs), where connectivity is intermittent and long delays are actually the norm. Traditional security protocols cannot completely address such problems in DTNs, hence an efficient algorithm to detect malicious nodes in DTNs is imperative. In this paper, we propose a misbehavior detection system to defend against blackhole and greyhole attacks. By collecting and securely exchanging data of previous encounters, a node can assess the trustworthiness of other nodes in order to detect blackhole and greyhole attacks. We evaluate our method through extensive simulations using different DTN routing protocols. Our simulation results show that even when the drop probability of greyhole attacks varies in a wide range, our approach can still efficiently detect evil nodes with a high detection rate and a low false positive rate while maintaining a low energy consumption.

Performance comparison of DTN bundle protocol implementations

In recent years, Delay Tolerant Networking (DTN) has received a lot of interest from the networking community. Today the Bundle Protocol (RFC 5050) is the standard communication protocol in DTNs and several implementations for various platforms are available. As of now, no quantitative analysis of the different implementations performance or a structured evaluation of interoperability has been undertaken. We performed interoperability checks and an extensive quantitative performance analysis of three Bundle Protocol implementations for Linux systems. In this paper we summarize our main findings. While the overall results show, that all implementations provide some baseline compatibility with each other, the stability and achieved performance under stress situations varies widely between implementations.

A bundle protocol implementation for android devices

In this demo we present IBR-DTN for Android: IBR-DTN is a fully featured RFC5050 compliant Bundle Protocol implementation that can run on un-rooted Android devices starting from Android Version 2.3 (Gingerbread). IBR-DTN for Android supports all features of the IBR-DTN version for PCs and embedded systems. It is available in the Google Play Store for free. In addition to the protocol stack we provide two simple real world applications: a text messaging system and a push-to-talk application. They can serve as an example how to build DTN applications for mobile phones as both applications as well as the protocol implementation itself are open sourced.

Undervolting in Real World WSN Applications: A Long-Term Study

The fault-tolerant character of WSN protocols and applications that do not assume completely reliable systems legitimize undervolting - a highly efficient energy management technique where the supply voltage is set below the minimum specifications. As has been shown in earlier work, by using thereliable IdealVolting undervolting scheme the lifetime of WSN applications can be increased significantly while keeping the node in a safe state even under rough environmental conditions. To show the usability of undervolting in a real world WSN deployment, we performed a long-term study of IdealVolting in a Smart Farming application. All measurements were performed on a generic outdoor testbed for WSNs (PotatoNet) which is also presented within this paper. We collected a long-term dataset of a WSN running for one farming season on a potato fieldto compare the reliability and performance characteristics of IdealVolting against a regular powered WSN.

Demo: PotatoNet -- Robust Outdoor Testbed for WSNs: Experiment like on your desk. Outside.

We present PotatoNet, an outdoor testbed for Wireless Sensor Networks (WSNs). Its primary focus is robustness, reliability and flexibility. PotatoNet is designed to operate without on-site maintenance for extended periods of time. It can withstand heat, dust and rain and has already been tested running outside for several months.

Piggy-Backing Link Quality Measurements to IEEE 802.15.4 Acknowledgements

In this paper we present an approach to piggyback link quality measurements to IEEE 802.15.4 acknowledgement frames by generating acknowledgements in software instead of relying on hardware support. We show that the software-generated ACKs can be sent meeting the timing constraints of IEEE 802.15.4. This allows for a standard conforming, energy neutral dissemination of link quality related information in IEEE 802.15.4 networks. This information is available at no cost when transmitting data and can be used as input for various schemes for adaptive transmission power control and to assess the current channel quality.

HYDRA: virtualized distributed testbed for DTN simulations

We present and evaluate HYDRA, a virtualized testbed for realistic large-scale network simulations. While classic simulation tools only provide approximations of the protocol stack, HYDRA virtualizes nodes running a complete Linux system. Mobility models and connection management integrated into HYDRA allow for the simulation of various wireless networking scenarios. Our distributed virtualization approach achieves excellent scalability and the automated node setup makes it easy to deploy large setups with hundreds of nodes. Hardware-in-the-loop simulations are possible, using HYDRA to augment a testbed of real devices. The ability to boot a HYDRA node completely from an USB flash drive enables the user to convert temporarily unused computer resources into a testbed without the need for any complex setup.

Mitigating Blackhole attacks in a hybrid VDTN

In the past we presented a delay tolerant network that used public buses and trams in the city of Braunschweig to monitor air pollution. Today, as smartphones are becoming computationally more powerful and offer a variety of communication interfaces, it becomes attractive to investigate whether smartphones and vehicular nodes can cooperate with each other, forming a network that can provide better quality of service to applications. In this paper, we evaluate the feasibility of creating an integrated Delay- and Disruption-Tolerant Network (DTN) consisting of smartphones and the public transportation system. Most importantly we propose a Misbehavior Detection System (MDS) to protect the security of the hybrid network. The evaluation results show that our MDS is able to efficiently detect attackers and defend the hybrid network against the interference of malicious nodes.