This work considers modern electric power grids, i.e. cyber-physical power systems, as networked, multi-converter power systems. From such a viewpoint, this paper presents a software and hardware platform for the integrated study of both the underlying communication network and the interaction of multiple, power converters within a single electric power microgrid. In particular, a microgrid energy management system was established that collects and provides data to a network simulator. The resulting platform allows for delays in both power control actuation and power data communication to be jointly studied. The inclusion of hardware resulted in data collection that intrinsically includes uncertainty. Subsequently, this platform can be used in both deterministic and stochastic analysis and control studies of cyber-physical power systems.

It is our great pleasure to welcome you to the 5th edition of the successful workshop on the Internet of Things: Smart Objects and Services (IoT-SoS), which is organized this year in conjunction with WoWMoM 2016. The main focus of this wokshop is to bring together experts from the research community, the industry and standardisation bodies and discuss in the context of heterogeneous networking technologies for the Internet of Things (IoT), aiming to identify solutions for addressing the key challenges that IoT brings to the networking domain.

The goal of this article is to develop a principled understanding of when it is beneficial to bundle technologies or services whose value is heavily dependent on the size of their user base, that is, exhibits positive exernalities. Of interest is how the joint distribution, and in particular the correlation, of the values users assign to components of a bundle affect its odds of success. The results offer insight and guidelines for deciding when bundling new Internet technologies or services can help improve their overall adoption. In particular, successful outcomes appear to require a minimum level of value correlation. Categories and Subject Descriptors (2012): Networks -- Network Algorithms -- Network economics; Networks -- Network properties -- Network dynamics; Information systems -- Information systems applications -- Collaborative and social computing systems and tools; Security and privacy -- Human and societal aspects of security and privacy; Human-centered computing -- Collaborative and social computing theory, concepts and paradigms

In this paper, we review why BGP is a poor candidate to facilitate the next generation of Software Defined Networks (SDN) and propose the Interdomain Management Layer (IML) architecture, a framework for facilitating interdomain resource sharing between these networks. IML uses a concept we call horizontal slicing, that allows SDN networks to become autonomous peers with other ASes, while maintaining centralized, operator-facing policy control and end-to- end flow control across interdomain boundaries.

It is a great pleasure to welcome you to the first edition of the IEEE Workshop on the Internet of Things: Smart Objects and Services.

In this paper, a quantitative study of the benefits and shortcomings of IP and MPLS traffic engineering techniques under realistic traffic variation scenarios is presented. While both techniques can achieve similar degree of optimization under steady state conditions, our simulation results show the impact on each when realistic traffic variations are induced in the network. A detailed simulator has been developed to facilitate the study, and several new metrics of interest are analyzed to present a novel point of view.

In this article, a new technique for grooming low-speed traffic demands into high-speed optical routes is proposed. This enhancement allows a transparent wavelength-routing switch (WRS) to aggregate traffic en route over existing optical routes without incurring expensive optical-electrical-optical (OEO) conversions. This implies that: a) an optical route may be considered as having more than one ingress node (all inline) and, b) traffic demands can partially use optical routes to reach their destination. The proposed optical routes are named "lighttours" since the traffic originating from different sources can be forwarded together in a single optical route, i.e., as taking a "tour" over different sources towards the same destination. The possibility of creating lighttours is the consequence of a novel WRS architecture proposed in this article, named "enhanced grooming" (G+). The ability to groom more traffic in the middle of a lighttour is achieved with the support of a simple optical device named lambda-monitor (previously introduced in the RingO project). In this article, we present the new WRS architecture and its advantages. To compare the advantages of lighttours with respect to classical lightpaths, an integer linear programming (ILP) model is proposed for the well-known multilayer problem: traffic grooming, routing and wavelength assignment The ILP model may be used for several objectives. However, this article focuses on two objectives: maximizing the network throughput, and minimizing the number of optical-electro-optical conversions used. Experiments show that G+can route all the traffic using only half of the total OEO conversions needed by classical grooming. An heuristic is also proposed, aiming at achieving near optimal results in polynomial time

Bandwidth constraint models have been a topic of intense discussions at the IETF meetings. Three conventional methods have been described in informational IETF RFCs and their performance on a single link has been analyzed and discussed in the literature. In this article, we take a further step into analyzing their performance and optimal bandwidth constraint setting for a real network scenario. A new model is proposed and compared to existing ones when failure events may cause preemption of traffic trunks in a network. Our simulations results provide great insight on the benefits of the methods.

Preemption and adaptation are two common techniques for controlling inelastic traffic such as streaming media. Adaptation policies dynamically increase or decrease the transmission rate of the stream in response to the presence or absence of network congestion. On the other hand, preemption policies select streams to be removed from the congested route. The removed streams may be rerouted through less favorable paths in the network. Adaptation causes a "virtual increase in network capacity" at the cost of reducing the client perceived stream quality (since rate reduction is achieved through lossy compression). Preemption permits improved blocking probabilities and traffic alignment on shortest paths for high priority traffic at the expense of performance degradation for low priority traffic. In this paper, we demonstrate the aforementioned performance trade-offs and the increased efficacy of control achievable through the combined use of preemption and adaptation policies.

The combined use of the differentiated services (DiffServ) and multiprotocol label switching (MPLS) technologies is envisioned to provide guaranteed quality of service (QoS) for multimedia traffic in IP networks, while effectively using network resources. These networks need to be managed adaptively to cope with the changing network conditions and provide satisfactory QoS. An efficient strategy is to map the traffic from different DiffServ classes of service on separate label switched paths (LSPs), which leads to distinct layers of MPLS networks corresponding to each DiffServ class. In this paper, three aspects of the management of such a layered MPLS network are discussed. In particular, an optimal technique for the setup of LSPs, capacity allocation of the LSPs and LSP routing are presented. The presented techniques are based on measurement of the network state to adapt the network configuration to changing traffic conditions.

An approach to dimensioning DiffServ/MPLS networks taking into account the per-class bandwidth reservation and fault tolerance cushion weights is proposed. Our dimensioning algorithm is based on Lagrange relaxation and it uses a bandwidth constraint model in order to provide per-class bandwidth reservation, and link costs which translate to backup LSP cushion weights. We propose an optimization formulation for our policy and also a polynomial time heuristic capable of approximating the optimal results. Besides a-priori dimensioning, a modified version of our dimensioning policy can also be run weekly/monthly in order to redimension LSPs according to the stored traffic history. Both the proposed heuristics have polynomial complexity and provides bounds on the value of the optimal objective function, which can be used to evaluate the accuracy of the results.

The preemption policy currently in use in MPLS-enabled commercial routers selects LSPs for preemption based only on their priority and holding time. This can lead to waste of resources and excessive number of rerouting decisions. In this paper, a new preemption policy is proposed and complemented with an adaptive scheme that aims to minimize rerouting. The new policy combines the three main preemption optimization criteria: number of LSPs to be preempted, priority of the LSPs, and preempted bandwidth. Weights can be configured to stress the desired criteria. The new policy is complemented by an adaptive scheme that selects lower priority LSPs that can afford to have their rate reduced. The selected LSPs will fairly reduce their rate in order to accommodate the new high-priority LSP setup request. Performance comparisons of a nonpreemptive approach, a policy currently in use by commercial routers, and our policies are also investigated.

A new algorithm for dynamic routing of LSPs is proposed. While off-line algorithms are not suitable due to the necessary a priori knowledge of future LSP setup requests, our proposed algorithm, SPeCRA (stochastic performance comparison routing algorithm), does not assume any specific stochastic traffic model and does not require any knowledge of future demands. Both features are a must for the new Internet traffic. In order to analyze SPeCRA's performance, we compare the ISP rejection ratios of SPeCRA and MIRA (Kar, K. et al., IEEE J. on Selected Areas in Commun., vol.18, no.12, p.2566-79, 2000). SPeCRA is easy to implement. It can be implemented using only simple shortest-hop or shortest-cost algorithms, which are interesting solutions for vendors, and not as computationally heavy as other routing algorithms.

In this paper, a new preemption policy is proposed and complemented with an adaptive scheme that aims to minimize rerouting. The preemption policy combines the three main optimization criteria: number of LSP to be preempted, priority of LSP to be preempted, and amount of bandwidth to be preempted. The preemption policy is complemented by an adaptive scheme that selects LSP with lower priority and reduces their rate in order to accommodate the new high-priority LSP setup request. Heuristics for both preemption and adaptive preemption policies are derived. Simulation results show the heuristics' accuracy. Performance comparisons of a non-preemptive approach, our preemption policy, the adaptive rate policy, and the policy in use by commercial routers are included.