A Lesson in Scaling 6LoWPAN -- Minimal Fragment Forwarding in Lossy Networks

This paper evaluates two forwarding strategies for fragmented datagrams in the IoT: hop-wise reassembly and a minimal approach to directly forward fragments. Minimal fragment forwarding is challenged by the lack of forwarding information at subsequent fragments in 6LoWPAN and thus requires additional data at nodes. We compared the two approaches in extensive experiments evaluating reliability, end-to-end latency, and memory consumption. In contrast to previous work and due to our alternate setup, we obtained different results and conclusions. Our findings indicate that direct fragment forwarding should be deployed only with care, since higher packet transmission rates on the link-layer can significantly reduce its reliability, which in turn can even further reduce end-to-end latency because of highly increased link-layer retransmissions.Comment: If you cite this paper, please use the LCN reference: M. S. Lenders, T. C. Schmidt, M. W\"ahlisch. "A Lesson in Scaling 6LoWPAN - Minimal Fragment Forwarding in Lossy Networks." in Proc. of IEEE LCN, 201

Old Wine in New Skins? Revisiting the Software Architecture for IP Network Stacks on Constrained IoT Devices

In this paper, we argue that existing concepts for the design and implementation of network stacks for constrained devices do not comply with the requirements of current and upcoming Internet of Things (IoT) use cases. The IoT requires not only a lightweight but also a modular network stack, based on standards. We discuss functional and non-functional requirements for the software architecture of the network stack on constrained IoT devices. Then, revisiting concepts from the early Internet as well as current implementations, we propose a future-proof alternative to existing IoT network stack architectures, and provide an initial evaluation of this proposal based on its implementation running on top of state-of-the-art IoT operating system and hardware.Comment: 6 pages, 2 figures and table

Connecting the World of Embedded Mobiles: The RIOT Approach to Ubiquitous Networking for the Internet of Things

The Internet of Things (IoT) is rapidly evolving based on low-power compliant protocol standards that extend the Internet into the embedded world. Pioneering implementations have proven it is feasible to inter-network very constrained devices, but had to rely on peculiar cross-layered designs and offer a minimalistic set of features. In the long run, however, professional use and massive deployment of IoT devices require full-featured, cleanly composed, and flexible network stacks. This paper introduces the networking architecture that turns RIOT into a powerful IoT system, to enable low-power wireless scenarios. RIOT networking offers (i) a modular architecture with generic interfaces for plugging in drivers, protocols, or entire stacks, (ii) support for multiple heterogeneous interfaces and stacks that can concurrently operate, and (iii) GNRC, its cleanly layered, recursively composed default network stack. We contribute an in-depth analysis of the communication performance and resource efficiency of RIOT, both on a micro-benchmarking level as well as by comparing IoT communication across different platforms. Our findings show that, though it is based on significantly different design trade-offs, the networking subsystem of RIOT achieves a performance equivalent to that of Contiki and TinyOS, the two operating systems which pioneered IoT software platforms

Security for the Industrial IoT: The Case for Information-Centric Networking

Industrial production plants traditionally include sensors for monitoring or documenting processes, and actuators for enabling corrective actions in cases of misconfigurations, failures, or dangerous events. With the advent of the IoT, embedded controllers link these `things' to local networks that often are of low power wireless kind, and are interconnected via gateways to some cloud from the global Internet. Inter-networked sensors and actuators in the industrial IoT form a critical subsystem while frequently operating under harsh conditions. It is currently under debate how to approach inter-networking of critical industrial components in a safe and secure manner. In this paper, we analyze the potentials of ICN for providing a secure and robust networking solution for constrained controllers in industrial safety systems. We showcase hazardous gas sensing in widespread industrial environments, such as refineries, and compare with IP-based approaches such as CoAP and MQTT. Our findings indicate that the content-centric security model, as well as enhanced DoS resistance are important arguments for deploying Information Centric Networking in a safety-critical industrial IoT. Evaluation of the crypto efforts on the RIOT operating system for content security reveal its feasibility for common deployment scenarios.Comment: To be published at IEEE WF-IoT 201

Securing name resolution in the IoT: DNS over CoAP

In this paper, we present the design, implementation, and analysis of DNS over CoAP (DoC), a new proposal for secure and privacy-friendly name resolution of constrained IoT devices. We implement different design choices of DoC in RIOT, an open-source operating system for the IoT, evaluate performance measures in a testbed, compare with DNS over UDP and DNS over DTLS, and validate our protocol design based on empirical DNS IoT data. Our findings indicate that plain DoC is on par with common DNS solutions for the constrained IoT but significantly outperforms when additional, CoAP standard features are used such as block-wise transfer or caching. With OSCORE for end-to-end security, we can save more than 10 kBytes of code memory compared to DTLS while enabling group communication without compromising the trust chain when using intermediate proxies or caches. We also discuss a scheme for very restricted links that compresses redundant or excessive information by up to 70%.Comment: 12 pages, 13 figures, 4 table

Fragment Forwarding in Lossy Networks

This paper evaluates four forwarding strategies for fragmented datagrams in the Internet of Things (IoT). We focus on classic end-to-end fragmentation, hop-wise reassembly, a minimal approach to direct forwarding of fragments, and direct forwarding utilizing selective fragment recovery. To fully analyze the potentials of selective fragment recovery, we include four common congestion control mechanisms. We compare all fragmentation strategies comprehensively in extensive experiments to assess reliability, end-to-end latency, and memory consumption on top of IEEE 802.15.4 and its common CSMA/CA MAC implementation. Our key findings include three takeaways. First, direct fragment forwarding should be deployed with care since higher packet transmission rates on the link layer can significantly reduce reliability, which can even further increase end-to-end latency because of highly increased link layer retransmissions. Second, selective fragment recovery can mitigate the problems underneath. Third, congestion control for selective fragment recovery should be chosen such that small congestion windows grow together with fragment pacing. In case of fewer fragments per datagram, pacing is less of a concern but the congestion window is limited by an upper bound

Betriebssysteme für Eingebettete Systeme im Internet der Dinge: Freie Fahrt für Experimentierfreudige

National audienceDie Betriebssystem-Welt im Internet der Dinge ist deutlich vielfältiger als die auf dem Desktop. „Everything is connected“ lautet hier das Schlagwort. Was Entwickler dazu wissen müssen.Les systèmes d'exploitations utilisés dans le domaine de l'Internet des Objets sont beaucoup plus divers que ceux utilisés dans le domaine des autres machines connectées (telles que desktops, laptops, tablettes et smartphones). Cet article donne un bref aperçu de ce qu'un développeur doit savoir à ce propos

Connecting the Dots : Selective Fragment Recovery in ICNLoWPAN

In this paper, we analyze the benefits of integrating 6LoWPAN Selective Fragment Recovery (SFR) in ICNLoWPAN. We present a solution that allows for immediate fragment forwarding - -a key feature of SFR - -in combination with ICN caching. Our proposal introduces a Virtual Reassembling Endpoint (VREP), which acts transparently as an SFR fragment forwarder while simultaneously collecting fragments. Once a datagram is complete, it is exposed to the content cache, effectively making the VREP the new fragmenting endpoint. Our solution complies with current specs defined in the IETF/IRTF. Furthermore, we combine the reverse path forwarding schemes of both SFR and ICNLoWPAN and assess drawbacks and benefits in a testbed. Our evaluation shows that SFR with VREP performs similar to hop-wise reassembly, details depend on the topology, but both outperform SFR without VREP in all scenarios

DNS Queries over CoAP (DoC)

This document defines a protocol for sending DNS messages over the Constrained Application Protocol (CoAP). These CoAP messages are protected by DTLS-Secured CoAP (CoAPS) or Object Security for Constrained RESTful Environments (OSCORE) to provide encrypted DNS message exchange for constrained devices in the Internet of Things (IoT)