Unconvinced, Unreconstructed, and Unrepentant: A Reply to Professor Friedman’s Response

Software defined networks are poised to dramatically simplify deployment and management of networks. OpenFlow, in particular, is becoming popular and starts being deployed. While the definition of the “northbound” API that can be used by the new services to interact with an OpenFlow controller is receiving considerable attention, the traditional, “southbound”, API that is used to program OpenFlow switches is far from perfect. In this paper, we analyze the current OpenFlow API and its usage in several controllers and show semantic differences between the intended and actual use. Thus, we argue for making the OpenFlow API clean and simple. In particular, we propose to mimic the process that exists in the Python community for deriving changes that result in a preferably only one, obvious way of performing a task. Toward this end, we propose three OpenFlow Enhancement Proposals: i) providing positive acknowledgment, ii) informing the controller about “silent” modifications, and iii) providing a partial order synchronization primitive.QC 20150704</p

The United Nations and the Human Rights Issue

This paper demonstrates a new class of bugs that is likely to occur in enterprise OpenFlow deployments. In particular, step-by-step, reactive establishment of paths can cause network-wide inconsistencies or performance- and space-related inefficiencies. The cause for this behavior is inconsistent packet processing: as the packets travel through the network they do not encounter consistent state at the OpenFlow controller. To mitigate this problem, we propose to use transactional semantics at the controller to achieve consistent packet processing. We detail the challenges in achieving this goal (including the inability to directly apply database techniques), as well as a potentially promising approach. In particular, we envision the use of multi-commit transactions that could provide the necessary serialization and isolation properties without excessively reducing network performance.QC 20140707</p

Is the Network Turing-Complete?

Ensuring correct network behavior is hard. This is the case even for simple networks, and adding middleboxes only complicates this task. In this paper, we demonstrate a fundamental property of networks. Namely, we show a way of using a network to emulate the Rule 110 cellular automaton. We do so using just a set of network devices with simple features such as packet matching, header rewriting and round-robin loadbalancing. Therefore, we show that a network can emulate any Turing machine. This ultimately means that analyzing dynamic network behavior can be as hard as analyzing an arbitrary program. Analyzing a network containing middleboxes is already understood to be hard. Our result shows that using even only statically configured switches can make the problem intractable

Role of innate signalling pathways in the immunogenicity of alphaviral replicon-based vaccines

<p>Abstract</p> <p>Background</p> <p>Alphaviral replicon-based vectors induce potent immune responses both when given as viral particles (VREP) or as DNA (DREP). It has been suggested that the strong immune stimulatory effect induced by these types of vectors is mediated by induction of danger signals and activation of innate signalling pathways due to the replicase activity. To investigate the innate signalling pathways involved, mice deficient in either toll-like receptors or downstream innate signalling molecules were immunized with DREP or VREP.</p> <p>Results</p> <p>We show that the induction of a CD8⁺T cell response did not require functional TLR3 or MyD88 signalling. However, IRF3, converging several innate signalling pathways and important for generation of pro-inflammatory cytokines and type I IFNs, was needed for obtaining a robust primary immune response. Interestingly, type I interferon (IFN), induced by most innate signalling pathways, had a suppressing effect on both the primary and memory T cell responses after DREP and VREP immunization.</p> <p>Conclusions</p> <p>We show that alphaviral replicon-based vectors activate multiple innate signalling pathways, which both activate and restrict the induced immune response. These results further show that there is a delicate balance in the strength of innate signalling and induction of adaptive immune responses that should be taken into consideration when innate signalling molecules, such as type I IFNs, are used as vaccine adjuvant.</p

Mass surveillance and technological policy options: Improving security of private communications

The 2013 Snowden revelations ignited a vehement debate on the legitimacy and breadth of intelligence operations that monitor the Internet and telecommunications worldwide. The ongoing invasion of the private sphere of individuals around the world by governments and companies is an issue that is handled inadequately using current technological and organizational measures. This article(1) argues that in order to retain a vital and vibrant Internet, its basic infrastructure needs to be strengthened considerably. We propose a number of technical and political options, which would contribute to improving the security of the Internet. It focuses on the debates around end-to-end encryption and anonymization, as well as on policies addressing software and hardware vulnerabilities and weaknesses of the Internet architectureThis work has been partially funded by the European Parliament, under the following contract number: 03210-02-00/5127/9840

Consistent Packet Processing - Because Consistent Updates Are Not Enough

In this poster and demo, we showcase a new class of problems that can occur due to inconsistent packet processing at an OpenFlow controller. We proceed to outline a potential solution

Developing an input-output based method to estimate a national-level energy return on investment (EROI)

Concerns have been raised that declining energy return on energy investment (EROI) from fossil fuels, and low levels of EROI for alternative energy sources, could constrain the ability of national economies to continue to deliver economic growth and improvements in social wellbeing while undertaking a low-carbon transition. However, in order to test these concerns on a national scale, there is a conceptual and methodological gap in relation to calculating a national-level EROI and analysing its policy implications. We address this by developing a novel application of an Input-Output methodology to calculate a national-level indirect energy investment, one of the components needed for calculating a national-level EROI. This is a mixed physical and monetary approach using Multi-Regional Input-Output data and an energy extension. We discuss some conceptual and methodological issues relating to defining EROI for a national economy, and describe in detail the methodology and data requirements for the approach. We obtain initial results for the UK for the period 1997–2012, which show that the country’s EROI has been declining since the beginning of the 21st Century. We discuss the policy relevance of measuring national-level EROI and propose avenues for future research

5-deazaflavin derivatives as inhibitors of p53 ubiquitination by HDM2

Based on previous reports of certain 5-deazaflavin derivatives being capable of activating the tumour suppressor p53 in cancer cells through inhibition of the p53-specific ubiquitin E3 ligase HDM2, we have conducted an structure–activity relationship (SAR) analysis through systematic modification of the 5-deazaflavin template. This analysis shows that HDM2-inhibitory activity depends on a combination of factors. The most active compounds (e.g., 15) contain a trifluoromethyl or chloro substituent at the deazaflavin C9 position and this activity depends to a large extent on the presence of at least one additional halogen or methyl substituent of the phenyl group at N10. Our SAR results, in combination with the HDM2 RING domain receptor recognition model we present, form the basis for the design of drug-like and potent activators of p53 for potential cancer therapy