Performance Comparison of VPN Solutions

Virtual Private Networks (VPN) is the state-of-the-art method to build secure connections between remote hosts over public networks. In times of high-speed connections to the internet, a need for personal information security and business cases, like cloud computing, high data throughput and a stable connection are increasingly important. Benchmarks of VPN solutions have been discussed in related work, but the data is quite old or uses other setups. Furthermore, we noticed that the benchmarks from the WireGuard whitepaper seem unrealistic, even if we take protocol overhead into account. In this work, we have decided to conduct VPN benchmarks ourselves. In the following paragraphs we describe our setup and look at three heavily used VPN solutions: OpenVPN, IPsec and WireGuard

A Survey of Scheduling in Time-Sensitive Networking (TSN)

TSN is an enhancement of Ethernet which provides various mechanisms for real-time communication. Time-triggered (TT) traffic represents periodic data streams with strict real-time requirements. Amongst others, TSN supports scheduled transmission of TT streams, i.e., the transmission of their packets by edge nodes is coordinated in such a way that none or very little queuing delay occurs in intermediate nodes. TSN supports multiple priority queues per egress port. The TAS uses so-called gates to explicitly allow and block these queues for transmission on a short periodic timescale. The TAS is utilized to protect scheduled traffic from other traffic to minimize its queuing delay. In this work, we consider scheduling in TSN which comprises the computation of periodic transmission instants at edge nodes and the periodic opening and closing of queue gates. In this paper, we first give a brief overview of TSN features and standards. We state the TSN scheduling problem and explain common extensions which also include optimization problems. We review scheduling and optimization methods that have been used in this context. Then, the contribution of currently available research work is surveyed. We extract and compile optimization objectives, solved problem instances, and evaluation results. Research domains are identified, and specific contributions are analyzed. Finally, we discuss potential research directions and open problems.Comment: 34 pages, 19 figures, 9 tables 110 reference

Phrenic nerve palsy during ablation of atrial fibrillation using a 28-mm cryoballoon catheter: predictors and prevention

Purpose: The purposes of this study were to determine whether predictors of phrenic nerve palsy (PNP) exist and to test whether a standardized ablation protocol may prevent PNP during cryoballoon (CB) ablation using the 28mm CB. Methods: Three-dimensional (3D) geometry of the pulmonary veins (PV) and their relationship to the superior vena cava (SVC) was analyzed. Phrenic nerve (PN) stimulation was performed during ablation of the right-sided PVs with a 28-mm CB. The freezing cycle was immediately terminated in case of loss of PN capture. Results: Sixty-five patients (age, 58 ± 11years; ejection fraction, 0.59 ± 0.06; left atrial size, 40 ± 5mm) with paroxysmal atrial fibrillation were included. No persistent PNP was observed. Transient PNP occurred in 4 of 65 patients (6%). PN function normalized within 24h in all four patients. A short distance between the right superior PV and the SVC was significantly associated with PNP, but left atrial and 3D PV anatomy were not. Low temperature early during the freezing cycle (<−41°C at 30s) predicted PNP with a sensitivity and a specificity of 100 and 98%, respectively. Conclusion: The anatomical relationship between the right superior PV and the SVC is a preprocedural predictor for the development of transient PNP, and low temperature early during ablation at the right superior PV is a sensitive warning sign of impending PNP. Despite the use of the 28mm CB, transient PNP occurred in 6% of patients undergoing CB ablatio

High-sensitivity cardiac Troponin T delta concentration after repeat pulmonary vein isolation

Introduction: Difference between high-sensitivity cardiac troponin T concentrations (hs-cTnT) before and after ablation procedure (delta concentration) reflects the amount of myocardial injury. The aim of the study was to investigate hs-cTnT prognostic power for predicting atrial fibrillation (AF) recurrence after repeat pulmonary vein isolation (PVI) procedure. Materials and methods: Consecutive patients with paroxysmal AF undergoing repeat PVI using a focal radiofrequency catheter were included in the study. Hs-cTnT was measured before and 18-24 hours after the procedure. Standardized 3, 6 and 12-month follow-up was performed. Cox-regression analysis was used to identify predictors of AF recurrence. Results: A total of 105 patients undergoing repeat PVI were analysed (24% female, median age 61 years). Median (interquartile range) hs-cTnT delta after repeat PVI was 283 (127 - 489) ng/L. After a median follow-up of 12 months, AF recurred in 24 (23%) patients. A weak linear relationship between the total radiofrequency energy delivery time and delta hs-cTnT was observed (Pearson R2 = 0.31, P = 0.030). Delta Hs-cTnT was not identified as a significant long-term predictor of AF recurrence after repeated PVI (P = 0.920). Conclusion: This was the first study evaluating the prognostic power of delta hs-cTnT in predicting AF recurrence after repeat PVI. Delta hs-cTnT does not predict AF recurrence after repeat PVI procedures. Systematic measurement of hs-cTnT after repeat PVI does not add information relevant to outcome

Quantitative assessment of a second-generation cryoballoon ablation catheter with new cooling technology—a perspective on potential implications on outcome

Purpose: The purpose of this study was to assess the differences in cooling behavior between the first-generation cryoballoon (CB-1G) and the second-generation cryoballoon (CB-2G) quantitatively to understand the freezing capabilities and to benefit from the improved efficacy of the CB-2G in patients with atrial fibrillation. Methods: We analyzed quantitatively the ice formation of the CB-1G and CB-2G catheters in vitro in a 37°C warm water bath during freezing for 60, 120, 180, 240, and 300s, respectively. Results: The mean-covered surface area and the relative coverage of the ice spots on the CB-2G were significantly different from the spots on the CB-1G for the 28-mm CBs but not for the 23-mm CBs. Whereas for the CB-1G, the ice formation was discontiguous with four isolated ice spots; the CB-2G showed a contiguous ice cap covering the entire distal part including the pole of the balloon. No homogeneous cooling behavior could be observed at the equatorial level with both catheters. Temporal differences on the ice formation could be observed for the 28-mm CB-2G but not for the 23-mm CB-2G. Conclusion: The new-generation CB-2G showed more powerful and homogeneous cooling behavior, especially for the 28-mm CB. Whether this translates into higher long-term success rates is currently unknown. The impact of the more effective cooling and the longer dissolving duration of the ice cap of the new-generation CB-2G on procedural safety needs to be investigated

Effective reduction of fluoroscopy duration by using an advanced electroanatomic-mapping system and a standardized procedural protocol for ablation of atrial fibrillation: ‘the unleaded study'

Aims It is recommended to keep exposure to ionizing radiation as low as reasonably achievable. The aim of this study was to determine whether fluoroscopy-free mapping and ablation using a standardized procedural protocol is feasible in patients undergoing pulmonary vein isolation (PVI). Methods and results Sixty consecutive patients were analysed: Thirty consecutive patients undergoing PVI using Carto3 were treated using a standardized procedural fluoroscopy protocol with X-ray being disabled after transseptal puncture (Group 1) and compared with a set of previous 30 consecutive patients undergoing PVI without a specific recommendation regarding the use of fluoroscopy (Group 2). The main outcome measures were the feasibility of fluoroscopy-free mapping and ablation, total fluoroscopy time, total dose area product (DAP), and procedure time. Sixty patients (age 60 ± 10 years, 73% male, ejection fraction 0.55 ± 0.09, left atrium 42 ± 8 mm) were included. In Group 1, total fluoroscopy time was 4.2 (2.6-5.6) min and mapping and ablation during PVI without using fluoroscopy was feasible in 29 of 30 patients (97%). In Group 2, total fluoroscopy time was 9.3 (6.4-13.9) min (P < 0.001). Total DAP was 13.2 (6.2-22.2) Gy*cm2 in Group 1 compared with 17.5 (11.7-29.7) Gy*cm2 in Group 2 (P = 0.036). Total procedure time did not differ between Groups 1 (133 ± 37 min) and 2 (134 ± 37 min, P = 0.884). Conclusion Performing mapping and ablation guided by an electroanatomic-mapping system during PVI without using fluoroscopy after transseptal puncture using a standardized procedural protocol is feasible in almost all patients and is associated with markedly decreased total fluoroscopy duration and DA