Search

The demands on mobile networks are constantly evolving, but designing and integrating new high-speed packet processing remains a challenge due to the complexity of requirements and opacity of protocol specifications. 5G data planes should be implemented in programmable hardware for both speed and flexibility, and extending or replacing these data planes should be painless. In this paper we implement the 5G data plane using two P4 programs: one that acts as a open-source model data plane to simplify the interface with the control plane, and one to run efficiently on hardware switches to minimize latency and maximize bandwidth. The model data plane enables testing changes made to the control plane before integrating with a performant data plane, and vice versa. The hardware data plane implements the fast path for device traffic, and makes use of microservices to implement functions that highspeed switch hardware cannot do. Our data plane implementation is currently in limited deployment on three university campuses where it is enabling new research on mobile networks.

With the dramatic increase in data traffic envisioned for the next years, operator’s network will be requested to sustain a large amount of data traffic, while at the same time being more flexible easily upgradable and having a lower total cost ownership (TCO). The industry at large is shifting towards SDN architectures, with white-box devices and open source software as building blocks. Such trend allows for further optimization across network layers, packet and optical as an example, with shared infrastructure and control. In this paper, we demonstrate a full end-to-end multi-stage data-center solution, combining leaf-spine control from Trellis, dedicated optical link provisioning by ODTN, and switches and packet optical programmable devices managed by Stratum.Unifying optical and Ethernet capabilities, the Cassini packet-optical transponder acts as a spine in the intra data-center Trellis leaf spine topology, and as the transponder for the DCI inter data-center links.We will describe the implemented architecture, the overall topology, the changes required to achieve the end to end solution and the challenges faced. We then outline the benefits of the proposed solution in terms of resource consumption, end to end optimisation, reliability and resiliency based upon data collected in a physical setup at ONF. Finally, we conclude this paper with future work and proposed optimisations.

The pandemic diffusion of the SARS-CoV-2 infection throughout the world required measures to prevent and strategies to control the infection, as well as the reallocation of the hospital structures in order to take care of an increased number of infected patients. Endoscopy Units should be able to perform endoscopic procedures on COVID-19 infected as well as on noninfected patients. The aim of this manuscript is to propose a model for a fast reorganization of the endoscopy department environment in order to safely perform endoscopic procedures in this Pandemic COVID-19 scenario, according to the current advices given by the Scientific Societies.

Stratum is an open source network operating system (NOS)that provides a common implementation of P4Runtime and OpenConfig interfaces for white box switches. This demonstration will show an SDN leaf-spine fabric of Stratum-enabled white box switches managed by the ONOS SDN controller. The switching chips (ASICs)and platforms will come from different vendors, but they will share a common P4-defined pipeline and set of OpenConfig models.

When medical therapy is unable to achieve biochemical control of secondary hyperparathyroidism, parathyroidectomy (PTX) is indicated, fortunately in a minority of patients. Thus, data on PTX prevalence and biochemical control are limited and, in particular in Italy, date back to 1999. We designed a prospective, observational and multicenter study to collect data from dialysis units distributed throughout the Italian regions. Clinical data were collected with a dedicated data sheet. From January to December 2010, 149 Centers serving a total of 12,515 patients provided data on 528 living PTX cases (PTX prevalence = 4.2%). Prevalence was higher in hemo- than in peritoneal dialysis (4.5 vs. 1.9%, X2 = 21.52; p

We tackle the problem of a network switch enforcing fair bandwidth sharing of the same link among many TCP-like senders. Most of the mechanisms to solve this problem are based on complex scheduling algorithms, whose feasibility becomes very expensive with today's line rate requirements, i.e. 10–100 Gbit/s per port. We propose a new scheme called FDPA in which we do not modify the scheduler, but instead we use an array of rate estimators to dynamically assign traffic flows to an existing strict priority scheduler serving only few queues. FDPA is inspired by recent advances in programmable stateful data planes. We propose a design that uses primitives common in data plane abstractions such as P4 and OpenFlow. We conducted experiments on a physical 10 Gbit/s testbed, we present preliminary results showing that FDPA produces fairness comparable to approaches based on scheduling.

Software Defined Networking envisions smart centralized controllers governing the forwarding behavior of dumb low-cost switches. But are "dumb" switches an actual strategic choice, or (at least to some extent) are they a consequence of the lack of viable alternatives to OpenFlow as programmatic data plane forwarding interface? Indeed, some level of (programmable) control logic in the switches might be beneficial to offload logically centralized controllers (de facto complex distributed systems) from decisions just based on local states (versus network-wide knowledge), which could be handled at wire speed inside the device itself. Also, it would reduce the amount of flow processing tasks currently delegated to specialized middleboxes. The underlying challenge is: can we devise a stateful data plane programming abstraction (versus the stateless OpenFlow match/action table) which still entails high performance and remains consistent with the vendors' preference for closed platforms? We posit that a promising answer revolves around the usage of extended finite state machines, as an extension (super-set) of the OpenFlow match/action abstraction. We concretely turn our proposed abstraction into an actual table-based API, and, perhaps surprisingly, we show how it can be supported by (mostly) reusing core primitives already implemented in OpenFlow devices.

Supporting the programming of stateful packet forwarding functions in hardware has recently attracted the interest of the research community. When designing such switching chips, the challenge is to guarantee the ability to program functions that can read and modify data plane's state, while keeping line rate performance and state consistency. Current state-of-the-art designs are based on a very conservative all-or-nothing model: programmability is limited only to those functions that are guaranteed to sustain line rate, with any traffic workload. In effect, this limits the maximum time to execute state update operations. In this paper, we explore possible options to relax these constraints by using simulations on real traffic traces. We then propose a model in which functions can be executed in a larger but bounded time, while preventing data hazards with memory locking. We present results showing that such flexibility can be supported with little or no throughput degradation., Comment: 6 pages

Background. Automatic systems for stabilizing blood pressure (BP) during dialysis are few and only control those variables indirectly related to BP. Due to complex BP regulation under dynamic dialysis conditions, BP itself appears to be the most consistent input parameter for a device addressed to preventing dialysis hypotension (DH). Methods. An automatic system (ABPS, automatic blood pressure stabilization) for BP control by fluid removal feedback regulation is implemented on a dialysis machine (Dialog Advanced, Braun). A fuzzy logic (FL) control runs in the system, using instantaneous BP as the input variable governing the ultrafiltration rate (UFR) according to the BP trend. The system is user-friendly and just requires the input of two data: critical BP (individually defined as the possible level of DH risk) and the highest UFR applicable (percentage of the mean UFR). We evaluated this system’s capacity to prevent DH in 55 RDT hypotension-prone patients. Sessions with (treatment A) and without (treatment B) ABPS were alternated one-by-one for 30 dialysis sessions per patient (674 with ABPS vs 698 without). Results. Despite comparable treatment times and UF volumes, severe DH appeared in 8.3% of sessions in treatment A vs 13.8% in treatment B (� 39%, P ¼ 0.01). Mild DH fell non-significantly (� 12.3%). There was a similar percentage of sessions in which the planned body weight loss was not achieved and dialysis time was prolonged. Conclusions. In conclusion, FL may be suited to interpreting and controlling the trend of a determined multi-variable parameter like BP. The medical knowledge of the patient and the consequent updating of input parameters depending on the patient’s clinical conditions seem to be the main factors for obtaining optimal results.

When dealing with node or link failures in Software Defined Networking (SDN), the network capability to establish an alternative path depends on controller reachability and on the round trip times (RTTs) between controller and involved switches. Moreover, current SDN data plane abstractions for failure detection (e.g. OpenFlow "Fast-failover") do not allow programmers to tweak switches' detection mechanism, thus leaving SDN operators still relying on proprietary management interfaces (when available) to achieve guaranteed detection and recovery delays. We propose SPIDER, an OpenFlow-like pipeline design that provides i) a detection mechanism based on switches' periodic link probing and ii) fast reroute of traffic flows even in case of distant failures, regardless of controller availability. SPIDER can be implemented using stateful data plane abstractions such as OpenState or Open vSwitch, and it offers guaranteed short (i.e. ms) failure detection and recovery delays, with a configurable trade off between overhead and failover responsiveness. We present here the SPIDER pipeline design, behavioral model, and analysis on flow tables' memory impact. We also implemented and experimentally validated SPIDER using OpenState (an OpenFlow 1.3 extension for stateful packet processing), showing numerical results on its performance in terms of recovery latency and packet losses., 8 pages

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., 6 pages, 9 figures

This paper presents a hardware implementation of Openstate, an extension of OpenFlow that allows performing stateful control functionalities directly inside the switch, without requiring the intervention of an external controller. The paper shows how, with a minimal reworking of the OpenFlow's basic architecture, and reusing the same building blocks, it is possible to greatly extend the intelligence of an OpenFlow switch allowing the offload of many control task directly in the switch. An FPGA based implementation of an Openstate prototype is here presented, the different architectural design choices are discussed, and the performance and limitations of the developed prototype are examinated. Finally, the paper proposes a discussion on the performance achievable by using an ASIC implementation of the OpenState switch1.

Dent’s disease (DD) involves nephrocalcinosis, urolithiasis, hypercalciuria, LMW proteinuria, and renal failure in various combinations. Males are affected. It is caused by mutations in the chloride channel CLCN5 gene. It has been suggested that DD is underdiagnosed, occurring in less overt forms, apparently without family history. A possible approach to this problem is to search for CLCN5 mutations in patients who may have a high prevalence of mutations: end-stage renal disease (ESRD) patients with previous calcium, struvite, or radio-opaque (CSR) stones. We looked for CLCN5 mutations in 25 males with ESRD–CSR stones selected from all of the patients (1,901 individuals, of which 1,179 were males) of 15 dialysis units in the Veneto region. One DD patient had a new DD mutation (1070 G>T) in exon 7. The new polymorphism IVS11–67 C>T was detected in intron 11 in one patient and one control. We also found 28 females with ESRD and stone history, and seven more males with ESRD and non-CSR stones. The prevalence of stone formers among dialysis patients in our region was 3.2%, much lower than the prevalence observed in older studies. Struvite stones continue to play a major role in causing stone-associated ESRD .

Equivalence of information from single versus multiple frequency bioimpedance vector analysis in hemodialysis. Background In suspended cells, low-frequency current only passes through extracellular fluids, while current at higher frequencies passes through extra- and intracellular fluids. Cells in soft tissues are in contact with each other, which causes tissue anisotropy, meaning that impedance changes along different cell directions, with part of low-frequency current also passing through cells. Hence, equivalent information on body impedance change is expected at all frequencies, which we proved in a dynamic condition of fluid removal with hemodialysis. Methods We performed whole-body impedance spectroscopy (496 frequencies from 4 to 1024kHz, SEAC SFB3 analyzer; Brisbane, Australia) before and during fluid removal (0, 60, 120, 180min, 2.5kg) in 67 hemodialysis patients. With increasing current frequency, resistance (R) decreases and reactance (Xc) moves along the Cole's semicircle on the R-Xc plane. Results The Cole's semicircles progressively enlarged and moved to the right on the R-Xc plane following fluid removal (increase in both R and Xc values at any given frequency). Xc values at 5kHz (expected values close to 0 Ohm) were 70% of the maximun Xc, indicating an intracellular current flows at low frequencies. The correlation coefficient between R at 50kHz (standard frequency) and R at other frequencies ranged from 0.96 to 0.99, and the correlation coefficient between Xc at 50kHz and Xc at other frequencies at any time point ranged from 0.65 to 0.99. Conclusion From high Xc values at low frequency, tissue anisotropy is inferred. Intra- and extracellular current flow causes equivalence of information based on functions of R and Xc measurements made at 50kHz versus other frequencies.

A reliable and scalable mechanism to provide protection against a link or node failure has additional requirements in the context of SDN and OpenFlow. Not only it has to minimize the load on the controller, but it must be able to react even when the controller is unreachable. In this paper we present a protection scheme based on precomputed backup paths and inspired by MPLS crankback routing, that guarantees instantaneous recovery times and aims at zero packet-loss after failure detection, regardless of controller reachability, even when OpenFlow's "fast-failover" feature cannot be used. The proposed mechanism is based on OpenState, an OpenFlow extension that allows a programmer to specify how forwarding rules should autonomously adapt in a stateful fashion, reducing the need to rely on remote controllers. We present the scheme as well as two different formulations for the computation of backup paths., 8 pages, pre-print, Design of Reliable Communication Networks (DRCN), 2015 11th International Conference on the

SUMMARY When dealing with node or link failures in software-defined networking (SDN), the network capability to establish an alternative path depends on controller reachability and on the round-trip times between controller and involved switches. Moreover, current SDN data plane abstractions for failure detection, such as OpenFlow “Fast-failover,” do not allow programmers to tweak switches' detection mechanism, thus leaving SDN operators relying on proprietary management interfaces (when available) to achieve guaranteed detection and recovery delays. We propose SPIDER, an OpenFlow-like pipeline design that provides (i) a detection mechanism based on switches' periodic link probing and (ii) fast reroute of traffic flows even in the case of distant failures, regardless of controller availability. SPIDER is based on stateful data plane abstractions such as OpenState or P4, and it offers guaranteed short (few milliseconds or less) failure detection and recovery delays, with a configurable trade-off between overhead and failover responsiveness. We present here the SPIDER pipeline design, behavioral model, and analysis on flow tables' memory impact. We also implemented and experimentally validated SPIDER using OpenState (an OpenFlow 1.3 extension for stateful packet processing) and P4, showing numerical results on its performance in terms of recovery latency and packet loss.

Calcitriol therapy is effective in the treatment of secondary hyperparathyroidism both during intravenous and oral administration, but there are doubts about the length of therapy and the duration of results. There are conflicting reports about results in size and activity of enlarged glands studied by ultrasound and double-tracer-subtraction-scintigraphy (DTSS). In 12 patients, 1 microgram of calcitriol was administered three times a week, intravenously and orally in alternate modes, for 46 weeks (therapy period) and orally for 46 weeks (follow-up period). During therapy, parathyroid hormone levels decreased in all patients, and in eight decreased by about 50% and were maintained at low levels during follow-up in five patients. Nine enlarged glands were detected by ultrasonography at the start of the study, and four hotspots were detected by DTSS; ultrasonography and DTSS were repeated at the end of the therapy and at the end of the follow-up: ultrasonography did not yield any significant variation in size, while one hot spot disappeared on DTSS. Basing their judgment on the lower cost of oral rather than intravenous administration, and on the good results of oral therapy, the authors stress the advisability of taking into account clinical and financial considerations before choosing the route of administration.

Cardiovascular disease represents the most common cause for the excess of morbidity and mortality found in end-stage renal disease (ESRD) and has prompted the exploration of multiple approaches to improve outcomes in these patients. Cardiovascular risk factors such as increased oxidative stress (OxSt) and inflammation are found in ESRD patients. A vitamin E-coated dialyzer using polysulfone membranes has been suggested to have positive effects on these factors. This 1-year study evaluated in 25 ESRD patients under chronic dialysis, the effects of a vitamin E-coated membrane (VitabranE ViE) "ex vivo" on mononuclear cells, OxSt, and inflammation-related biochemical and molecular biology markers using a molecular biology approach. p22(phox), heme oxygenase (HO)-1, plasminogen activator inhibitor (PAI)-1 protein level, and phosphorylated extracellular signal-regulated kinase (pERK)1/2 status were evaluated at the beginning of the study, after 6 months and after 12 months by Western blot analysis and oxidized low-density lipoprotein (OxLDL) plasma level by enzyme-linked immunosorbent assay, alongside vascular remodeling assessment as measured by carotid intima-media thickness (IMT) in a subgroup of nine randomly selected patients. p22(phox), PAI-1, OxLDL, and pERK all decreased with VitabranE use, while HO-1 increased. Carotid IMT did not increase. Treatment with VitabranE significantly decreases the expression of proteins and markers relevant to OxSt and inflammation tightly associated with cardiovascular disease, and it appears highly likely that VitabranE use will provide a benefit in terms of cardiovascular protection.

Cardiovascular disease represents the most common cause for the excess of morbidity and mortality found in end-stage renal disease (ESRD) and has prompted the exploration of multiple approaches to improve outcomes in these patients. Cardiovascular risk factors such as increased oxidative stress (OxSt) and inflammation are found in ESRD patients. A vitamin E-coated dialyzer using polysulfone membranes has been suggested to have positive effects on these factors. This 1-year study evaluated in 25 ESRD patients under chronic dialysis, the effects of a vitamin E-coated membrane (VitabranE ViE) "ex vivo" on mononuclear cells, OxSt, and inflammation-related biochemical and molecular biology markers using a molecular biology approach. p22(phox), heme oxygenase (HO)-1, plasminogen activator inhibitor (PAI)-1 protein level, and phosphorylated extracellular signal-regulated kinase (pERK)1/2 status were evaluated at the beginning of the study, after 6 months and after 12 months by Western blot analysis and oxidized low-density lipoprotein (OxLDL) plasma level by enzyme-linked immunosorbent assay, alongside vascular remodeling assessment as measured by carotid intima-media thickness (IMT) in a subgroup of nine randomly selected patients. p22(phox), PAI-1, OxLDL, and pERK all decreased with VitabranE use, while HO-1 increased. Carotid IMT did not increase. Treatment with VitabranE significantly decreases the expression of proteins and markers relevant to OxSt and inflammation tightly associated with cardiovascular disease, and it appears highly likely that VitabranE use will provide a benefit in terms of cardiovascular protection.

Introduction: Vitamin D receptor activator (VDRA) therapy has been shown to be associated with reduced mortality rates in chronic kidney disease (CKD) patients with secondary hyperparathyroidism (SHPT). However, differences between VDRAs in their ability to reduce both all-cause and cardiovascular-related mortality rates are not yet fully elucidated. Methods: The objective of the current analysis was to determine the effect of VDRA therapy on mortality in an Italian dialysis population, observed prospectively every 6 months for 18 months. Patients were investigated for all-cause and cardiovascular-related mortality risk adjusted for various demographic, clinical, and/or SHPT treatment variables. Results: The cumulative probabilities of all-cause and cardiovascular-related mortality were lower for patients who received any VDRA treatment compared with those who did not (p < 0.001) regardless of all measured variables. Additionally, patients who received paricalcitol and/or cinacalcet (with or without VDRAs) compared with calcitriol showed a significant improvement in both all-cause and cardiovascular-related mortality (p < 0.001). Cinacalcet with or without VDRAs was not associated with a further decrease of mortality hazard ratios compared with paricalcitol monotherapy. Conclusions: VDRA therapy (associated or not with cinacalcet) was associated with improved survival in dialysis patients, independent of demographic and clinical variables.

The first reports of interstitial fibrosis leading to rapidly progressing chronic renal failure (CRF) in young women undergoing slimming treatment appeared at the beginning of the 1990s in Belgium. These slimming pills erroneously contained powdered roots of plants - picked in China - belonging to the Aristolochia instead of Stephania tetranda family. In the following years, after new cases had occurred worldwide, the term aristolochic acid nephropathy (AAN) came into use. Despite numerous warnings from various post-marketing surveillance institutes, products containing aristolochic acid are still widely used by Asiatic herbal practitioners and easily available on the Internet, where they are marketed without being subject to any regulations. In 2002 the IARC (International Agency for Research on Cancer) conclusively recognized the urothelial carcinogenicity of aristolochic acid. Because of the globalization and the growing use of phytotherapy worldwide, nephrologists should take into account AAN as a possible cause of CRF. In addition to assessing the direct kidney toxicity caused by some products used in phytotherapy, the authors conclude that it is necessary to research more closely possible drug interactions and side effects of commonly used herbs such as Echinacea, Gingko biloba, St. John's wort, ginseng, and garlic, which patients consider to be natural, non-toxic and self-prescribed remedies and whose use they therefore seldom disclose to their doctors.

Background. Increased oxidative stress (OxSt) as well as inflammation are risk factors for cardiovascular events and determinant of cardiovascular disease which remains the most common cause of excess morbidity and mortality for end-stage renal disease ESRD patients. Haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) has been shown to have a positive impact on markers of inflammation while its effect on OxSt is not known. Methods. This study evaluates in haemodialysis patients the effect of HFR on the plasma level of oxidized LDL (OxLDL), a marker of OxSt, and mononuclear cell gene and protein expression of OxSt-related proteins such as p22 phox (subunit of NAD(P)H oxidase), PAI-1 (induced by OxSt and atherothrombogenetic) and haeme-oxygenase-1 (HO-1) (induced by OxSt). Fourteen patients were randomized into two groups in a crossover design, treated for 6 month periods with HFR (SG8 Plus-Bellco, Mirandola, Italy) or low-flux bicarbonate dialysis (HD) using a polysulphone dialyser 1.8 m 2 . Blood samples were collected at the beginning of the study, after 6 months (crossover) and after 12 months. Results. ANOVA analysis of the data performed to rule out any crossover effect in either sequence was not significant and thus data from both sequences were combined and then analysed further statistically. HFR reduced mRNA production and protein expression of p22 phox and PAI-1 compared with HD (� 9 � 5 vs 2 � 6 %, P < 0.0001 and � 15 � 20 vs 3 � 17 %, P < 0.05 for p22 phox ; � 19 � 6 vs � 5 � 5 %, P < 0.0001 and � 24 � 12 vs 9 � 15 %, P < 0.0001 for PAI-1). HO-1 was unchanged (� 12 � 8 vs � 10 � 8 % and � 21 � 12 vs � 14 � 8 %) while plasma OxLDL was reduced (� 14 � 19 vs 1 � 14 %, P < 0.01). Conclusions. The results of our study indicate that HFR treatment, compared with standard dialysis, has a lower impact on OxSt. Given, the strong relationship between OxSt and inflammation and their impact on the long-term cardiovascular complications in endstage renal disease patients, HFR might have a more beneficial impact in reducing the risk of atherosclerotic cardiovascular disease in dialysis patients.