scholarly journals On the Tradeoff between Performance and Programmability for Software Defined WiFi Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Tausif Zahid ◽  
Xiaojun Hei ◽  
Wenqing Cheng ◽  
Adeel Ahmad ◽  
Pasha Maruf
Keyword(s):  
Performance Optimization ◽  
Traffic Flows ◽  
Network Access ◽  
Performance Measurements ◽  
Throughput Performance ◽  
Wifi Networks ◽  
Traffic Loads ◽  
High Bandwidth ◽  
Potential Benefits ◽  
Sdn Controller

WiFi has become one of the major network access networks due to its simple technical implementation and high-bandwidth provisioning. In this paper, we studied software defined WiFi networks (SDWN) against traditional WiFi networks to understand the potential benefits, such as the ability of SDWN to effectively hide the handover delay between access points (AP) of the adoption of the SDWN architecture on WiFi networks and identify representative application scenarios where such SDWN approach could bring additional benefits. This study delineated the performance bottlenecks such as the throughput degradation by around 50% compared with the conventional WiFi networks. In addition, our study also shed some insights into performance optimization issues. All of the performance measurements were conducted on a network testbed consisting of a single basic service set (BSS) and an extended service set (ESS) managed by a single SDN controller deployed with various laboratory settings. Our evaluation included the throughput performance under different traffic loads with different number of nodes and packet sizes for both TCP and UDP traffic flows. Handover delays were measured during the roaming phase between different APs against the traditional WiFi networks. Our results have demonstrated the tradeoff between performance and programmability of software defined APs.

scholarly journals Proposed statistical-based approach for detecting distribute denial of service against the controller of software defined network (SADDCS)

2018 ◽  
Vol 218 ◽  
pp. 02012 ◽  
Author(s):  
Mohammad A. AL-Adaileh ◽  
Mohammed Anbar ◽  
Yung-Wey Chong ◽  
Ahmed Al-Ani
Keyword(s):  
Statistical Analysis ◽  
Denial Of Service ◽  
Attack Detection ◽  
Detection Accuracy ◽  
Ddos Attacks ◽  
Large Area ◽  
Network Resources ◽  
Network Resource ◽  
High Bandwidth ◽  
Sdn Controller

Software-defined networkings (SDNs) have grown rapidly in recent years be-cause of SDNs are widely used in managing large area networks and securing networks from Distributed Denial of Services (DDoS) attacks. SDNs allow net-works to be monitored and managed through centralized controller. Therefore, SDN controllers are considered as the brain of networks and are considerably vulnerable to DDoS attacks. Thus, SDN controller suffer from several challenges that exhaust network resources. For SDN controller, the main target of DDoS attacks is to prevent legitimate users from using a network resource or receiving their services. Nevertheless, some approaches have been proposed to detect DDoS attacks through the examination of the traffic behavior of networks. How-ever, these approaches take too long to process all incoming packets, thereby leading to high bandwidth consumption and delays in the detection of DDoS at-tacks. In addition, most existing approaches for the detection of DDoS attacks suffer from high positive/negative false rates and low detection accuracy. This study proposes a new approach to detecting DDoS attacks. The approach is called the statistical-based approach for detecting DDoS against the controllers of software-defined networks. The proposed approach is designed to detect the presence of DDoS attacks accurately, reduce false positive/negative flow rates, and minimize the complexity of targeting SDN controllers according to a statistical analysis of packet features. The proposed approach passively captures net-work traffic, filters traffic, and selects the most significant features that contribute to DDoS attack detection. The general stages of the proposed approach are (i) da-ta preprocessing, (ii) statistical analysis, (iii) correlation identification between two vectors, and (iv) rule-based DDoS detection.

scholarly journals Performance Optimization of Visible Light Communication

2021 ◽  
Vol 9 ◽  
Author(s):  
Agha Yasir Ali ◽  
◽  
Lubna Farhi ◽  
Usama Ahmed ◽  
Asad Subhan ◽  
...  
Keyword(s):  
Visible Light ◽  
Bit Error Rate ◽  
Performance Optimization ◽  
Visible Light Communication ◽  
Data Rate ◽  
Modulation Scheme ◽  
Performance Parameters ◽  
Trade Off ◽  
High Bandwidth ◽  
Ber Performance

This paper focuses to analyze the data rate, bit error rate (BER), flickering & bandwidth of visible light communication (VLC) system. The existing modulation scheme ON-OFF Keying (OOK) is modified and produces the trade-off between these parameters. The modified ON-OFF Keying (MOOK) is proposed in which the variation in the transmitted pulses is investigated. Therefore, the square and rectangular pulses are used to transmit zero and one bits respectively. The duty cycle of square pulse is increased to improve the flickering performance. Moreover, it utilized the bandwidth and deteriorates the BER performance. The differential MOOK (DMOOK) modulation scheme is also proposed in which the ON period of square pulse (zero bits) is removed. Therefore, the data rate of DMOOK is increased because the duration of zero bit pulse is decreased. Similarly, the high bandwidth is utilized and BER performance deteriorates. All performance parameters are evaluated on Arduino based hardware VLC system. We conclude that the BER performance deteriorates by improving flickering performance and data rate of the VLC system.

Throughput Performance Optimization of Super Dense Wireless Networks With the Renewal Access Protocol

2016 ◽  
Vol 15 (5) ◽  
pp. 3440-3452 ◽  
Author(s):  
Yunbae Kim ◽  
Ganguk Hwang ◽  
Jungsun Um ◽  
Sungjin Yoo ◽  
Hoiyoon Jung ◽  
...  
Keyword(s):  
Wireless Networks ◽  
Performance Optimization ◽  
Throughput Performance ◽  
Access Protocol ◽  
Dense Wireless Networks

scholarly journals A strategy of quick hierarchization of road bridge maintenance activities

2020 ◽  
Vol 80 (ET.2020) ◽  
pp. 1-18
Author(s):  
Giovanni Andriulo
Keyword(s):  
Degradation Process ◽  
Economic Resources ◽  
Traffic Flows ◽  
Crucial Aspect ◽  
Traffic Loads ◽  
Bridge Maintenance ◽  
Environmental Actions ◽  
Structure State ◽  
Logical Tool ◽  
Maintenance Activities

The control and maintenance of infrastructures is a crucial aspect for the sustainability and development of the economic and social activities of a country. The managing authorities, in order to preserve the efficiency and safety of the traffic flows, have to deal with a rather old infrastructure asset that is often in a non-optimal conservation state with an increasing degradation process induced by the increment of the traffic loads and by the environmental actions. The situation is exacerbated by the limited economic resources and reduced workforces at disposal with the consequence that an order of priority in the maintenance plain is anavoidable. This work provides a logical tool to define the hierarchy of the maintenance plain of the infrastructural heritage based on one hand on the structure state of conservation and on the other hand on the context in which the construction is integrated

scholarly journals Efficient Concurrent Execution of Smart Contracts in Blockchain Sharding

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yan Wang ◽  
Jixin Li ◽  
Wansheng Liu ◽  
Aiping Tan
Keyword(s):  
Performance Optimization ◽  
Concurrency Control ◽  
Critical Issue ◽  
Smart Contracts ◽  
Throughput Performance ◽  
Concurrent Execution ◽  
Blockchain Technology ◽  
Smart Contract ◽  
Execution Strategy ◽  
Feature Information

Throughput performance is a critical issue in blockchain technology, especially in blockchain sharding systems. Although sharding proposals can improve transaction throughput by parallel processing, the essence of each shard is still a small blockchain. Using serial execution of smart contract transactions, performance has not significantly improved, and there is still room for improvement. A smart contract concurrent execution strategy based on concurrency degree optimization is proposed for performance optimization within a single shard. This strategy is applied to each shard. First, it characterizes the conflicting contract feature information by executing a smart contract, analyzing the factors that affect the concurrent execution of the smart contracts, and clustering the contract transaction. Second, in shards with high transaction frequency, considering the execution time, conflict rate, and available resources of contract transactions, finding a serializable schedule of contract transactions by redundant computation and a Variable Shadow Speculative Concurrency Control (SCC-VS) algorithm for smart contract scheduling is proposed. Finally, experimental results show that the strategy increases the concurrency of smart contract execution by 39% on average and the transaction throughput of the whole system by 21% on average.

scholarly journals Network Slicing on 5G Vehicular Cloud Computing Systems

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1474
Author(s):  
Emmanouil Skondras ◽  
Angelos Michalas ◽  
Dimitrios J. Vergados ◽  
Emmanouel T. Michailidis ◽  
Nikolaos I. Miridakis ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Cloud Computing ◽  
Energy Consumption ◽  
Multiple Input Multiple Output ◽  
Access Network ◽  
Network Access ◽  
Network Slicing ◽  
Vehicular Cloud Computing ◽  
Vehicular Cloud ◽  
Sdn Controller

Fifth generation Vehicular Cloud Computing (5G-VCC) systems support various services with strict Quality of Service (QoS) constraints. Network access technologies such as Long-Term Evolution Advanced Pro with Full Dimensional Multiple-Input Multiple-Output (LTE-A Pro FD-MIMO) and LTE Vehicle to Everything (LTE-V2X) undertake the service of an increasing number of vehicular users, since each vehicle could serve multiple passenger with multiple services. Therefore, the design of efficient resource allocation schemes for 5G-VCC infrastructures is needed. This paper describes a network slicing scheme for 5G-VCC systems that aims to improve the performance of modern vehicular services. The QoS that each user perceives for his services as well as the energy consumption that each access network causes to user equipment are considered. Subsequently, the satisfactory grade of the user services is estimated by taking into consideration both the perceived QoS and the energy consumption. If the estimated satisfactory grade is above a predefined service threshold, then the necessary Resource Blocks (RBs) from the current Point of Access (PoA) are allocated to support the user’s services. On the contrary, if the estimated satisfactory grade is lower than the aforementioned threshold, additional RBs from a Virtual Resource Pool (VRP) located at the Software Defined Network (SDN) controller are committed by the PoA in order to satisfy the required services. The proposed scheme uses a Management and Orchestration (MANO) entity implemented by a SDN controller, orchestrating the entire procedure avoiding situations of interference from RBs of neighboring PoAs. Performance evaluation shows that the suggested method improves the resource allocation and enhances the performance of the offered services in terms of packet transfer delay, jitter, throughput and packet loss ratio.

scholarly journals Detection of Misconfigured Wi-Fi Tethering in Managed Networks

2020 ◽  
Author(s):  
Jaehyuk Choi
Keyword(s):  
Operating Systems ◽  
Throughput Performance ◽  
Selfish Behavior ◽  
Detection Scheme ◽  
Unfair Advantage ◽  
Clear Channel Assessment ◽  
Throughput Gain ◽  
Potential Benefits ◽  
Google Android ◽  
Clear Channel

Wi-Fi tethering using a mobile device (e.g., a smartphone or a tablet) as a hotspot for other devices has become a common practice. Despite the potential benefits of Wi-Fi tethering, the open source nature of mobile operating systems (e.g., Google Android) can be abused by a selfish device to manipulate channel-access parameters to gain an unfair advantage in throughput performance. This can cause serious performance problems within a well-planned Wi-Fi network due to an unauthorized selfish or misconfigured tethering device interfering with nearby well-planned access points (APs). In this paper, we demonstrate that the selfish behavior of a tethering node that adjusts the clear channel assessment (CCA) threshold has strong adverse effects in a multi-AP network, while providing the selfish node a high throughput gain. To mitigate this problem, we present a passive online detection scheme that identifies the network condition and detects selfish tethering nodes with high accuracy by exploiting the packet loss information of on-going transmissions. To the best of our knowledge, this is the first research to consider the problem of detecting a selfish tethering node in managed Wi-Fi networks.

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