Thomas C. Schmidt

RIOT OS: Towards an OS for the Internet of Things

The Internet of Things (IoT) is characterized by heterogeneous devices. They range from very lightweight sensors powered by 8-bit microcontrollers (MCUs) to devices equipped with more powerful, but energy-efficient 32-bit processors. Neither a traditional operating system (OS) currently running on Internet hosts, nor typical OS for sensor networks are capable to fulfill the diverse requirements of such a wide range of devices. To leverage the IoT, redundant development should be avoided and maintenance costs should be reduced. In this paper we revisit the requirements for an OS in the IoT. We introduce RIOT OS, an OS that explicitly considers devices with minimal resources but eases development across a wide range of devices. RIOT OS allows for standard C and C++ programming, provides multi-threading as well as real-time capabilities, and needs only a minimum of 1.5 kB of RAM.

Information centric networking in the IoT: experiments with NDN in the wild

This paper explores the feasibility, advantages, and challenges of an ICN-based approach in the Internet of Things. We report on the first NDN experiments in a life-size IoT deployment, spread over tens of rooms on several floors of a building. Based on the insights gained with these experiments, the paper analyses the shortcomings of CCN applied to IoT. Several interoperable CCN enhancements are then proposed and evaluated. We significantly decreased control traffic (i.e., interest messages) and leverage data path and caching to match IoT requirements in terms of energy and bandwidth constraints. Our optimizations increase content availability in case of IoT nodes with intermittent activity. This paper also provides the first experimental comparison of CCN with the common IoT standards 6LoWPAN/RPL/UDP.

Backscatter from the data plane - Threats to stability and security in information-centric network infrastructure

Information-centric networking (ICN) raises data objects to first class routable entities in the network and changes the Internet paradigm from host-centric connectivity to data-oriented delivery. However, current approaches to content routing heavily rely on data-driven protocol events and thereby introduce a strong coupling of the control to the data plane in the underlying routing infrastructure. In this paper, threats to the stability and security of the content distribution system are analyzed in theory, simulations, and practical experiments. We derive relations between state resources and the performance of routers, and demonstrate how this coupling can be misused in practice. We further show how state-based forwarding tends to degrade by decorrelating resources. We identify intrinsic attack vectors present in current content-centric routing, as well as possibilities and limitations to mitigate them. Our overall findings suggest that major architectural refinements are required prior to global ICN deployment in the real world.

Tomorrow's In-Car Interconnect? A Competitive Evaluation of IEEE 802.1 AVB and Time-Triggered Ethernet (AS6802)

Ethernet-based in-car communication is currently a hot topic in the automotive industry. Soon Ethernet will start to oust MOST bus in its domain of info- and entertainment applications. However, the full benefit of a technologically integrated in-car network will only become rewarding with the deployment of an Ethernet-based backbone that integrates all automotive domains on a single layer at increased bandwidth, reduced complexity and cost, while opening car intelligence for future innovations. Such backbone must transport critical control data in real-time. Standard Ethernet requires extensions to comply with the strict timing requirements of driver assistance and safety applications while simultaneously supporting broadband multimedia traffic. In this paper, we compare IEEE 802.1 AVB and Time-triggered Ethernet, two competing real-time approaches. While the first fosters over- provisioning and prioritisation, the second is based on a coordinated time-division-multiple-access (TDMA) policy for media access. By simulating a realistic in-car backbone design and traffic model, we reveal the strengths and weaknesses of both protocols and point to the diverging characteristics of event- and time-triggered policies. Our results show that in this in-car network scenario both protocols are able to meet the rigid timing requirements, while each has its unique benefits and disadvantages.

Comparing time-triggered Ethernet with FlexRay: An evaluation of competing approaches to real-time for in-vehicle networks

FlexRay is considered the next generation state-of-the-art technology for in-car networks, while time-triggered Ethernet emerges with the promise to integrate real-time and best-effort traffic into one homogeneous backbone. This paper contributes a competitive analysis of FlexRay and time-triggered Ethernet. By showing that it is possible to transfer a fully utilized FlexRay system to a system based on time-triggered Ethernet, it is demonstrated that time-triggered Ethernet is a suitable replacement of current in-vehicle bus-systems. Further it is shown that a switched system has advantages in bandwidth utilization over a shared bus, when using group communication.

Towards detecting BGP route hijacking using the RPKI

Prefix hijacking has always been a big concern in the Internet. Some events made it into the international world-news, but most of them remain unreported or even unnoticed. The scale of the problem can only be estimated. The Resource Publication Infrastructure (RPKI) is an effort by the IETF to secure the inter-domain routing system. It includes a formally verifiable way of identifying who owns legitimately which portion of the IP address space. The RPKI has been standardized and prototype implementations are tested by Internet Service Providers (ISPs). Currently the system holds already about 2% of the Internet routing table. Therefore, in theory, it should be easy to detect hijacking of prefixes within that address space. We take an early look at BGP update data and check those updates against the RPKI---in the same way a router would do, once the system goes operational. We find many interesting dynamics, not all can be easily explained as hijacking, but a significant number are likely operational testing or misconfigurations.

An exchange format for multimodal annotations

This paper presents the results of a joint effort of a group of multimodality researchers and tool developers to improve the interoperability between several tools used for the annotation and analysis of multimodality. Each of the tools has specific strengths so that a variety of different tools, working on the same data, can be desirable for project work. However this usually requires tedious conversion between formats. We propose a common exchange format for multimodal annotation, based on the annotation graph (AG) formalism, which is supported by import and export routines in the respective tools. In the current version of this format the common denominator information can be reliably exchanged between the tools, and additional information can be stored in a standardized way.

Leveraging WebRTC for P2P content distribution in web browsers

WebRTC enables web applications to establish a direct communication channel between two browsers without relaying the data through a web server. It consists of an API [1] defined by the W3C and a set of underlying protocols defined by the IETF Rtcweb Working Group [2]. The possibility of establishing peer-to-peer channels between two browsers and the expected broad deployment opens the opportunity for new use cases that were not possible until now.

Global serverless videoconferencing over IP

In recent years the capabilities of the common Internet infrastructure have increased to an extent where data intensive communication services may mature to become popular, reliable applications. Videoconferencing over IP can be seen as such a highly prominent candidate. However, heavy infrastructure and complicated call handling hinder acceptance of standard solutions.This paper presents a more lightweight framework--both communication scheme and conferencing software--to overcome these deficiencies. A simple, ready-to-use global location scheme for conference users is proposed. First practical experiences are reported.

A FAST WAVELET-BASED VIDEO CODEC AND ITS APPLICATION IN AN IP VERSION 6-READY SERVERLESS VIDEOCONFERENCING SYSTEM

The purpose of this paper is twofold: On the one hand, we propose a fast wavelet-based video codec which is implemented into a real-time video conferencing tool. The proposed codec uses temporal frame difference coding, a computationally low-complex 5/3 tap wavelet transform, and a fast entropy coding scheme based on Golomb–Rice codes. On the other hand, we present an application of the video conferencing tool in a serverless peer-to-peer IP-based communication framework. For mobile communication we propose a simple, ready-to-use location scheme for video conference users in a global network.