SEcure data-centric application eXtension (SeDAX) is a publish/subscribe information-centric networking architecture, where publishers send messages to the appropriate message broker over a Delaunay-triangulated overlay network. Resilient data forwarding and data redundancy enable a high level of reliability. Overlay nodes and topics are addressed via geo-coordinates. A topic is stored on primary and secondary nodes, those nodes closest and second-closest to the topic’s coordinate, respectively. The overlay automatically reroutes a topic’s messages to its secondary node should its primary node fail. In the original proposal, SeDAX determines the coordinate of a topic by hashing its name. This kind of topic allocation is static, which can lead to unintended load imbalances. We propose a topic delegation mechanism to make the assignment of topics to nodes dynamic. Our proposed mechanism is the only existing method to improve the flexibility and resource management of the SeDAX architecture so far. We define three resilience levels that allow information on the SeDAX overlay to survive 0, 1, or 2 node failures, imposing different loads on SeDAX nodes. For this elaborated SeDAX approach, we suggest a distributed resource management system that detects traffic imbalances among SeDAX nodes and re-assigns topics to other coordinates for load balancing purposes. We evaluate the load imbalance for the different resilience levels, for different topic characteristics, and in particular for topics with storage requirements growing over time. The proposed algorithm leads to well balanced load on SeDAX nodes while keeping load redistribution at a reasonable level.

C-DAX is a cyber-secure publish/subscribe middleware tailored to the needs of smart grids, offering end-to-end security, and scalable and resilient communication among participants in a smart grid. While C-DAX' broker-based publish/subscribe mechanisms are well-suited for scalable information dissemination with regard to high numbers of publishers and subscribers, (1) additional transmission delays are inherent to the design because of multi-hop application layer forwarding, and (2) interactive (probably legacy) applications are prohibited due to the one-way publish/subscribe paradigm and potential dependencies on IP communication. This work presents two advanced communication modes for the C-DAX architecture, addressing those issues: (1) broker-less publish/subscribe for delay-sensitive applications, and (2) transparent IP-tunneling over publish/subscribe for legacy applications. Those modes further improve C-DAX' suitability for smart grid applications, including enhanced real-time application support, and transparent support for legacy smart grid communication protocols.

Smart meter gateways are the core component of the advanced metering infrastructure in Germany, and provide a unified interface for metering data retrieval to third parties. Different standards and communication protocols exist for smart metering, ranging from transmission protocols to architectural recommendations. This work briefly presents the concept of the German BSI TR-03109 smart metering architecture, reviews implementations of smart metering protocols and architectures, and provides a Java-based open-source smart meter gateway experimentation framework (jOSEF). The proposed framework combines and extends established protocol frameworks to provide a flexible tool for the validation of smart metering communication use cases involving smart meter gateways.

IEEE C37.118 is the current standard for synchrophasor measurements in power systems.It defines the measurement method and communication protocols for the entities in a synchrophasor network.The standard offers two different modes for client-server communication, but cannot be used unchanged over publish/subscribe communication architectures, whose major advantage is simplified and incremental integration of new applications.This work reviews the communication part of IEEE C37.118, and provides an adapter-based solution to easily connect and integrate entities in a synchrophasor network over a publish/subscribe communication architecture.The proposed adapters offer standard-compliant communication between the synchrophasor measurement network entities to facilitate the exchange of measurement data.

The limited scalability, reliability, and security of today's utility communication infrastructures are main obstacles for the deployment of smart grid applications. The C-DAX project aims at providing a cyber-secure publish/subscribe middleware tailored to the needs of smart grids. C-DAX provides end-to-end security, and scalable and resilient communication among participants in a smart grid. This work presents the C-DAX security architecture, and proposes different key distribution mechanisms. Security properties are defined for control plane and data plane communication, and their underlying mechanisms are explained. The presented work is partially implemented in the C-DAX prototype and will be deployed in a field trial.

The electrical grid is changing from a centralized system with predictable and controllable power generation to a system integrating large numbers of distributed energy resources including weather-dependent renewables. As a consequence, the future retail energy market for electrical energy will have many more participants and see more volatile prices than today, creating the need for new communication and trading infrastructures facilitating. In this paper, we briefly review PowerMatcher as a possible approach for such an infrastructure, and analytically evaluate its communication characteristics. PowerMatcher is a multiagent based smart grid communication framework developed by TNO which enables market integration of distributed energy resources and automatic demand supply matching. While the trading side of the framework is well understood, there is no study that considers the communication side. Our results show that PowerMatcher enables scalable retail energy transactions with millions of participants requiring only moderate resources on the communication's side.

The evolution toward emerging active distribution networks (ADNs) can be realized via a real-time state estimation (RTSE) application facilitated by the use of phasor measurement units (PMUs). A critical challenge in deploying PMU-based RTSE applications at large scale is the lack of a scalable and flexible communication infrastructure for the timely (i.e., sub-second) delivery of the high volume of synchronized and continuous synchrophasor measurements. We address this challenge by introducing a communication platform called C-DAX based on the information-centric networking (ICN) concept. With a topic-based publish-subscribe engine that decouples data producers and consumers in time and space, C-DAX enables efficient synchrophasor measurement delivery, as well as flexible and scalable (re)configuration of PMU data communication for seamless full observability of power conditions in complex and dynamic scenarios. Based on the derived set of requirements for supporting PMU-based RTSE in ADNs, we design the ICN-based C-DAX communication platform, together with a joint optimized physical network resource provisioning strategy, in order to enable the agile PMU data communications in near real-time. In this paper, C-DAX is validated via a field trial implementation deployed over a sample feeder in a real-distribution network; it is also evaluated through simulation-based experiments using a large set of real medium voltage grid topologies currently operating live in The Netherlands. This is the first work that applies emerging communication paradigms, such as ICN, to smart grids while maintaining the required hard real-time data delivery as demonstrated through field trials at national scale. As such, it aims to become a blueprint for the application of ICN-based general purpose communication platforms to ADNs.

Limited scalability, reliability, and security of todays utility communication infrastructures are main obstacles to the deployment of smart grid applications. The C-DAX project aims at providing and investigating a communication middleware for smart grids to address these problems, applying the information-centric networking and publish/subscribe paradigm. We briefly describe the C-DAX architecture, and extend it with a flexible resilience concept, based on resilient data forwarding and data redundancy. Different levels of resilience support are defined, and their underlying mechanisms are described. Experiments show fast and reliable performance of the resilience mechanism.

SeDAX is a publish/subscribe information-centric networking architecture where publishers send messages to the appropriate message broker over a Delaunay-triangulated overlay network. Resilient data forwarding and data redundancy enable a high level of reliability. Overlay nodes and topics are addressed via geo-coordinates. A topic is stored on primary and secondary nodes, those nodes closest and second-closest to the topic's coordinate, respectively. The overlay automatically reroutes a topic's messages to its secondary node should its primary node fail. Currently, SeDAX determines the coordinate of a topic by hashing its name. This kind of topic allocation is static, which can lead to unintended load imbalances. In this paper, we propose a topic delegation mechanism to make the assignment of topics to nodes dynamic. Our proposed mechanism is the only existing method to improve the flexibility and resource management of the SeDAX architecture so far. We define the load of SeDAX nodes and coordinates at different levels of resilience. On this basis, we develop distributed algorithms for load balancing. Simulations show that significant load imbalance can occur with static topic assignment and that the proposed algorithms achieve very good load balancing results.

We develop and analyze algorithms that reduce the storage capacity required by SeDAX (Secure Data-centric Application eXtensible) in the presence of simultaneous node failures. The SeDAX infrastructure for smart grids uses data redundancy for a high level of reliability. It is an information-centric approach using resilient data forwarding in a Delaunay triangulated overlay. While SeDAX's data forwarding scheme is well understood, there is no study that considers the SeDAX storage capacity necessary to survive multiple node failures. Our results are compared with the theoretical lower bound of SeDAX and the lower bound of an idealized storage system. The presented algorithms can be used to reduce storage requirements of SeDAX in practice.

The locator/identifier split is a core principle of many recently proposed routing architectures for a scalable future Internet. It splits the function of today's IP addresses into two separate pieces. End-hosts are addressed using identifiers which are not globally routable while network attachment points have globally routable locators assigned. In most architectures, either the sending host or an intermediate node has to query a mapping system to obtain locators for identifiers. Such a mapping system must be fast, reliable, secure, and may be able to relay data packets. In this paper, we propose requirements and a general taxonomy for mapping systems and use it to provide a survey on recent proposals. We address general aspects of mapping systems and point out remaining research opportunities.

In this paper, we describe the C-DAX project. The main objective of the C-DAX project is to define and implement a novel and scalable information platform for implementing a cyber-secure data and control cloud for power grids, called CDAX. It will be validated to support various smart grid use cases and deployed for a trial in a live electricity network with realworld settings.

In this paper, we present a tool for performance measurement of InfiniBand networks. Our tool analyzes the network and presents a comprehensible visualization of the performance and health of the network. InfiniBand network operators can use the tool to detect potential bottlenecks and optimize the overall performance of their network.

The Locator/Identifier Separation Protocol (LISP) is a new naming and addressing architecture which is currently standardized in the IETF and which is deemed to improve the scalability and flexibility of the current routing architecture. LISP mobile node (LISP-MN) is an extension to the basic LISP architecture and enables mobile nodes to roam into LISP and non-LISP domains. The basic LISP architecture is currently deployed in a beta-network which can be used to test the protocol behavior on a smaller scale. However, a realistic simulation model for the LISP architecture and its various extensions is still missing. Such a simulation model could be used by researchers to quickly test new extensions on a larger scale for different load and network scenarios. In this paper, we describe the implementation of our model of the LISP architecture and its various extensions in the INET framework for OMNeT++. We present performance results to show the correctness of our model. As a first application, we used the simulation model to assess proposed improvements to LISP-MN and to verify our proposed NAT traversal mechanism for LISP-MN.