The European Rail Traffic Management System (ERTMS) is becoming a worldwide de facto standard for high-speed railway signaling. A major shortcoming of this system is that it is attached to a single radio-bearer technology, the Global System for Mobile Communications-Railway (GSM-R). The migration of ERTMS toward Internet Protocol (IP) provides the opportunity to make ERTMS unaware of the underlying communication technology by establishing train-to-ground connectivity via multiple bearers. In this article, we evaluate Multipath Transmission Control Protocol (MPTCP) integration in the ERTMS protocol stack in a test bed as a way to use heterogeneous radio bearers seamlessly and simultaneously. We validate this strategy by comparing our obtained results to the European Integrated Radio Enhanced Network (EIRENE) requirements and demonstrate its functionality as a seamless fail recovery strategy.

The evolution of the railway sector depends, to a great extent, on the deployment of advanced railway signalling systems. These signalling systems are based on communication architectures that must cope with complex electromagnetical environments. This paper is outlined in the context of developing the necessary tools to allow the quick deployment of these signalling systems by contributing to an easier analysis of their behaviour under the effect of electromagnetical interferences. Specifically, this paper presents the modelling of the Eurobalise-train communication flow in a general purpose simulation tool. It is critical to guarantee this communication link since any lack of communication may lead to a stop of the train and availability problems. In order to model precisely this communication link we used real measurements done in a laboratory equipped with elements defined in the suitable subsets. Through the simulation study carried out, we obtained performance indicators of the physical layer such as the received power, SNR and BER. The modelling presented in this paper is a required step to be able to provide quality of service indicators related to perturbed scenarios.

The deployment of wireless networks in critical industrial environments must ensure the availability of monitoring and control applications, for which it is essential to exploit redundancy techniques. In order to reduce to zero the failover time, in this paper, the Parallel Redundancy Protocol (PRP) is used in Wireless Local Area Networks (WLAN) which are implemented under the Software-Defined Networking (SDN) paradigm. It is discussed how the OpenFlow protocol allows an external controller to configure redundant paths between dual-homed devices. As a result, critical services can be protected in interference and mobility situations. The improvement in availability has been obtained by using both emulation and simulation.

The telecommunications landscape has been undergoing a major shift in recent years. Initially Software Defined Networking (SDN), and then Network Function Virtualization (NFV) have opened up new ways of looking at the increasingly demanding service provider scenario. The description of the service to be provided will be a key point determining the success in the integration and interoperability of the different proposals. However, the refined understanding of the future scenario and its requirements has recently introduced unique challenges in the path to fully achieve the benefits of the NFV vision. In this paper we review the proposals of service description in the main initiatives related to the NFV arena. Then we elaborate on key novel challenges and evaluate how the different proposals solve them. Finally, we propose a straw man model of service and resource description addressing these challenges and defining the features that would serve as design directions for future initiatives and updates in this topic.

The High-availability Seamless Redundancy (HSR) protocol guarantees zero recovery time in case of failure in ethernet networks. However, the management of HSR networks is static and inflexible. This, added to the bandwidth reduction due to data duplication, makes it difficult to efficiently control the network resources. An integration of HSR and OpenFlow technologies is proposed to provide redundancy control and traffic prioritization. As a result, a node can distinguish between critical and noncritical flows, protecting them according to their needs. The effectiveness of the priority-aware network is assessed in terms of throughput efficiency.

The cyber-security of several industrial plants has been compromised for last years by some worms and viruses, such as Stuxnet, which was able to take control of the Supervisory Control And Data Acquisition (SCADA) system of a nuclear plant in Iran. The research community and the international standardization committees raised their awareness about protecting information in Substation Automation Systems (SAS). IEC 61850-5 and IEC 62351-6 standards respectively describe communication models and the security mechanisms to be deployed in current substations, but they present some inconsistencies. On the one hand, this standard mandates that RSA cryptosystem must be used to provide source authenticity of GOOSE and SV messages. However, despite expensive processors with crypto accelerators were utilized, execution times would exceed the maximum transfer times stated in the standard for most time critical applications. On the other hand, the recommended synchronization solution is the Precision Time Protocol (PTP), as defined in IEEE 1588-2008, which introduced an optional security extension based on old keyed hash algorithms that has also been demonstrated to be suboptimal due to latency times and required resources. The aim of this paper is to explore current available security solutions and study their applicability to the substation environment. Furthermore, as part of the future security framework, a MACsec-based security approach that allows different communication services with diverse performance and security requirements to live together within the substation network is proposed.

Over the last few years, Software-Defined Networking (SDN) has emerged as one of the most disruptive and profitable novelties in networking. SDN was originally conceived to improve performance and reduce costs in Ethernet-based networks and it has been widely adopted in data center and campus networks. Similarly, thanks to the introduction of SDN concepts, access networks will benefit from the higher control, the lower maintenance costs and the better remote access to devices of SDN. However, its application to access networks is not straightforward and imposes great challenges to vendors and network operators, since current SDN technologies are not prepared to handle the provisioning of user equipment, specific port management or QoS requirements of common access networks. Most recent trends dealing with the SDN-ization of access networks advocate for the use of simple devices at the customer premises and the virtualization of the networking functionalities, requiring the provisioning of Layer 2 services in many cases. In such a scenario, this paper presents an architecture that brings SDN to common access networks using legacy equipment. In a nutshell, the architecture is based on the abstraction of the access network as a wide area OpenFlow switch where QoS-enabled pipes are dynamically created leveraging the high granularity of the OpenFlow protocol for packet classification. Furthermore, the OpenFlow protocol itself has been extended in order to support the advanced QoS requirements that are common to most access networks. The architecture has been implemented for DOCSIS access networks and it has been validated and evaluated using a real testbed deployed at our laboratory. The obtained results show that the architecture remains compliant with the ITU-T QoS recommendations and that the cost of introducing the elements required by the architecture in terms of service performance is negligible.