Sebastian Meiling

A scalable communication infrastructure for smart grid applications using multicast over public networks

The transition to regenerative energy resources paves the path from a small number of large power plants to a grid of highly distributed, heterogeneous small generators. To establish a Smart Grid it requires a scalable machine-to-machine communication that allows to control and coordinate millions of energy producing and consuming devices. In this work we contribute a future deployment concept of a scalable communication infrastructure for Smart Grids. Our proposal is based on group communication utilizing hybrid multicast over public networks. We show by real-world measurements that our approach achieves high scalability while also limiting end-to-end communication delay.

System-assisted service evolution for a future Internet — The H∀Mcast approach to pervasive multicast

The Internet has been successful in providing a uniformly available IPv4 unicast service, accessible via the socket API which eased application deployment. However, this tightly shaped concept failed to promote a heterogeneous network layer (including IPv6) or additional services like multicast. In this paper, we propose methods for diversifying the Internet service capabilities with the help of enhanced end system intelligence and an API abstraction towards the applications. We provide a general architecture for the example of hybrid adaptive mobile multicast (H∀Mcast) which allows for various realizations and pluralistic deployments. The achievement of our contribution is a universal, robust service access that allows group applications to run everywhere, no matter what the status of regional technological deployment will be.

Consumer-oriented integration of smart homes and smart grids: A case for multicast-enabled Home Gateways?

Smart Home automation is pushing into the consumer market for several years, while at the same time energy companies are working on the deployment of Smart Grids. Although, a key idea of the energy transition is to integrate small energy devices at the consumers site, the potential benefits of Smart Home technologies for Smart Grids remain unused at large until now. In this work we present a concept for consumer-oriented integration of Smart Home devices into Smart Grid applications using multicast-enabled Home Gateways. An evaluation using standard consumer hardware confirms general feasibility and performance of our approach. Further, we deployed a measurement testbed in the metropolitan area of Hamburg to analyze typical end-to-end Internet connectivity of consumer households.

Large-scale measurement and analysis of one-way delay in hybrid multicast networks

Group communication plays an important role in the distribution of real-time data for IPTV, multimedia conferencing, or online multiplayer games, but IP multicast remains unsupported in todays global Internet. Hybrid solutions that bridge between overlay and underlay multicast are a promising escape from the deployment dilemma of multicast. In this paper, we examine the real-time capabilities of hybrid multicast in a globally distributed environment based on our adaptive architecture H8Mcast within the Planet-Lab testbed. We present a large-scale measurement study and analysis of one-way packet delay distributions in several realistic group scenarios. The unique results in global traces of hybrid multicast data have been achieved by carefully tracking packets and continuously correcting clock offsets. Companion measurements of unicast-based distribution are part of our analysis, as well as the comparative discussion of our results with previous findings from theory and simulation. Our measurements reveal that about 50% of global group members experience a real-time compliant service within the conversational time bounds of 150 ms.

On name-based group communication: Challenges, concepts, and transparent deployment

Name-oriented networks introduce the vision of an information-centric, secure, globally available publish-subscribe infrastructure. Current approaches concentrate on unicast-based pull mechanisms and thereby fall short in automatically updating content at receivers. In this paper, we argue that an inclusion of multicast will grant additional benefits to the network layer, namely efficient distribution of real-time data, a manyto-many communication model, and simplified rendezvous pro cesses. These aspects are comprehensively reflected by a gro uporiented naming concept that integrates the various availa ble group schemes and introduces new use cases. A first draft of this name-oriented multicast access has been implemented i n the H∀Mcast middleware.

A middleware for transparent group communication of globally distributed actors

Actors have been designed for loosely coupled concurrent systems based on asynchronous message passing. This model is of particular relevance for Internet-wide distribution, but cannot unfold its full potential due to the lack of a globally available messaging service for groups. We present a message-oriented publish/subscribe middleware that enables global group communication at near-IP performance. Based on this transparent group layer, we build libcppa, an Actor library with modular support for group semantics that is compliant to the new C++ standard.

On performance and robustness of internet-based smart grid communication: A case study for Germany

Emerging Smart Grid solutions require an out-of-band communication channel to enable services such as advanced metering, demand side management, and virtual power plants. The Internet is able to host these highly distributed communication demands, leading the Smart Grid to become an Internet-dependent critical national infrastructure. In this work, we introduce a nation-centric perspective and methodology to shed light on performance and robustness of Internet-based Smart Grid communication. By presenting a case study for Germany, our contributions are: (a) we apply new methods to identify all stakeholders of the energy sector within a national Internet topology, (b) we analyze vulnerabilities of the corresponding communication (sub-)system as part of the current Internet, and (c) we extend our analysis to include Internet access networks of consumer households, where most Smart Grid applications will be implemented. Our findings indicate that the energy-related Internet subsystems are up to 2 times more robust to network failures than the national average. Further, Internet connectivity of consumers households achieves availability of > 99 % and is therefore suitable for most Smart Grid applications.

Towards a nation-centric understanding of the internet

Data communication in the Internet is based on the borderless interplay of Autonomous Systems (ASes). An AS abstracts one or multiple IP networks, which may be globally distributed, but is owned by an organization located in a country. Current research on the Internet structure mainly focuses on a global perspective or considers local, intra-domain properties. In this paper, we analyze nation-centric subsets of the Internet taken from the AS-level graph of Germany. Each subset reflects a public or industrial sector. Based on a classified set of relevant German ASes, we are able to perform detailed investigations of structural dependencies for the critical Internet infrastructure. We identify and visualize the importance of dedicated ASes within specific sectors, and quantify robustness of the communication communities. Our preliminary results indicate that members of sectoral groups tend to avoid direct peering, but connect via a small group of common ISPs. This results in an enhanced dependence (betweenness) on selected hubs as compared to the characteristics of larger networks.

Dynamic cross-domain group communication in hybrid multicast networks

Group communication based on multicast enables efficient one-to-many and many-to-many distribution of real-time data. Multicast communication would therefore be beneficial to popular Internet applications such as IPTV, on-line multiplayer games and audio/video conferencing, and is considered as an important network service for future CCN/ICN architectures. However, multicast exists in many flavors and technologies, and on different network layers with incompatible application interfaces and divergent states of deployment. Due to these challenges of multicast plurality, there is no multicast service available on the Internet today. In this paper, we present a dynamic and technology-transparent group communication scheme by names. We extend H∀Mcast - a hybrid multicast architecture - with a mapping service between technology dependent addressing and an abstract naming. Therefore we show in detail the required components and discuss possible solutions.

A monitoring framework for hybrid multicast networks

Many popular Internet applications like IPTV, video or voice chat, social networks and massive multiplayer online games communicate in groups. While IP layer multicast remains hesitant in global deployment, applications implement their own group distribution techniques at the price of higher complexity and lower efficiency. Emerging hybrid multicast approaches become a promising alternative to fill that gap. Hybrid multicast networks bridge between application and IP-layer multicast and gain multicast deployment at a system level throughout the Internet. In this paper, we present a monitoring framework for such hybrid multicast networks based on a common API in the process of standardization. Monitoring tools are useful to identify network failures and to improve the performance. The target of our monitoring framework is to collect, analyze and visualize node and routing information, thereby making the complexity of hybrid networks accessible to network administrators for the first time.