Traffic Management Applications for Stateful SDN Data Plane

The successful OpenFlow approach to Software Defined Networking (SDN) allows network programmability through a central controller able to orchestrate a set of dumb switches. However, the simple match/action abstraction of OpenFlow switches constrains the evolution of the forwarding rules to be fully managed by the controller. This can be particularly limiting for a number of applications that are affected by the delay of the slow control path, like traffic management applications. Some recent proposals are pushing toward an evolution of the OpenFlow abstraction to enable the evolution of forwarding policies directly in the data plane based on state machines and local events. In this paper, we present two traffic management applications that exploit a stateful data plane and their prototype implementation based on OpenState, an OpenFlow evolution that we recently proposed.Comment: 6 pages, 9 figure

Economic health-aware LPV-MPC based on system reliability assessment for water transport network

This paper proposes a health-aware control approach for drinking water transport networks. This approach is based on an economic model predictive control (MPC) that considers an additional goal with the aim of extending the components and system reliability. The components and system reliability are incorporated into the MPC model using a Linear Parameter Varying (LPV) modeling approach. The MPC controller uses additionally an economic objective function that determines the optimal filling/emptying sequence of the tanks considering that electricity price varies between day and night and that the demand also follows a 24-h repetitive pattern. The proposed LPV-MPC control approach allows considering the model nonlinearities by embedding them in the parameters. The values of these varying parameters are updated at each iteration taking into account the new values of the scheduling variables. In this way, the optimization problem associated with the MPC problem is solved by means of Quadratic Programming (QP) to avoid the use of nonlinear programming. This iterative approach reduces the computational load compared to the solution of a nonlinear optimization problem. A case study based on the Barcelona water transport network is used for assessing the proposed approach performance.Peer ReviewedPostprint (published version

Self-Healing Protocols for Connectivity Maintenance in Unstructured Overlays

In this paper, we discuss on the use of self-organizing protocols to improve the reliability of dynamic Peer-to-Peer (P2P) overlay networks. Two similar approaches are studied, which are based on local knowledge of the nodes' 2nd neighborhood. The first scheme is a simple protocol requiring interactions among nodes and their direct neighbors. The second scheme adds a check on the Edge Clustering Coefficient (ECC), a local measure that allows determining edges connecting different clusters in the network. The performed simulation assessment evaluates these protocols over uniform networks, clustered networks and scale-free networks. Different failure modes are considered. Results demonstrate the effectiveness of the proposal.Comment: The paper has been accepted to the journal Peer-to-Peer Networking and Applications. The final publication is available at Springer via http://dx.doi.org/10.1007/s12083-015-0384-

The Bankruptcy-Law Safe Harbor for Derivatives: A Path-Dependence Analysis

U.S. bankruptcy law grants special rights and immunities to creditors in derivatives transactions, including virtually unlimited enforcement rights. This article argues that these rights and immunities result from a form of path dependence, a sequence of industry-lobbied legislative steps, each incremental and in turn serving as apparent justification for the next step, without a rigorous and systematic vetting of the consequences. Because the resulting “safe harbor” has not been fully vetted, its significance and utility should not be taken for granted; and thus regulators, legislators, and other policymakers—whether in the United States or abroad—should not automatically assume, based on its existence, that the safe harbor necessarily reflects the most appropriate treatment of derivatives transactions under bankruptcy and insolvency law or the treatment most likely to minimize systemic risk

Fault management and service provisioning process model of next generation access networks

Network operators are nowadays upgrading their access networks to cope with the increasing number of users and the increasing bandwidth required by services. However, cost plays a crucial factor. In order to decide which next generation access network will be implemented, an accurate cost evaluation should be performed. This evaluation requires a total cost of ownership model including a detailed model of the most costly operational processes: fault management and customer provisioning. These models help identifying the most costly sub-processes, where network providers should improve their cost efficiency. This paper presents detailed models for these operational processes and gives an approach to use them for estimating future operational costs

The Bankruptcy-Law Safe Harbor for Derivatives: A Path-Dependence Analysis

U.S. bankruptcy law grants special rights and immunities to creditors in derivatives transactions, including virtually unlimited enforcement rights. This article argues that these rights and immunities result from a form of path dependence, a sequence of industry-lobbied legislative steps, each incremental and in turn serving as apparent justification for the next step, without a rigorous and systematic vetting of the consequences. Because the resulting “safe harbor” has not been fully vetted, its significance and utility should not be taken for granted; and thus regulators, legislators, and other policymakers—whether in the United States or abroad—should not automatically assume, based on its existence, that the safe harbor necessarily reflects the most appropriate treatment of derivatives transactions under bankruptcy and insolvency law or the treatment most likely to minimize systemic risk

Air Traffic Safety: continued evolution or a new Paradigm.

The context here is Transport Risk Management. Is the philosophy of Air Traffic Safety different from other modes of transport? – yes, in many ways, it is. The focus is on Air Traffic Management (ATM), covering (eg) air traffic control and airspace structures, which is the part of the aviation system that is most likely to be developed through new paradigms. The primary goal of the ATM system is to control accident risk. ATM safety has improved over the decades for many reasons, from better equipment to additional safety defences. But ATM safety targets, improving on current performance, are now extremely demanding. What are the past and current methodologies for ATM risk assessment; and will they work effectively for the kinds of future systems that people are now imagining and planning? The title contrasts ‘Continued Evolution’ and a ‘New Paradigm’. How will system designers/operators assure safety with traffic growth and operational/technical changes that are more than continued evolution from the current system? What are the design implications for ‘new paradigms’, such as the USA’s ‘Next Generation Air Transportation System’ (NextGen) and Europe’s Single European Sky ATM Research Programme (SESAR)? Achieving and proving safety for NextGen and SESAR is an enormously tough challenge. For example, it will need to cover system resilience, human/automation issues, software/hardware performance/ground/air protection systems. There will be a need for confidence building programmes regarding system design/resilience, eg Human-in-the-Loop simulations with ‘seeded errors’