scholarly journals Hybrid SDN Performance: Switching between Centralized and Distributed Modes under Unreliable Control Communication Channels

2021 ◽  
Vol 10 (3) ◽  
pp. 57
Author(s):  
Mohammed Osman ◽  
Josep Mangues-Bafalluy
Keyword(s):  
Packet Loss ◽  
Network Performance ◽  
Communication Channels ◽  
Cost Effective ◽  
Packet Losses ◽  
Control Packet ◽  
Network Operation ◽  
Channel Packet ◽  
The Impact ◽  
Hybrid Sdn

Software-defined networking generally assumes ideal control channels between controller and network nodes. This may not be the case in challenged environments that are becoming more common due to dense and reduced-coverage 5G deployments and use cases requiring cost-effective wireless transport networks. In this paper, we evaluate the impact on network performance of unreliable controller-to-node communication channels, propose a hybrid SDN (hSDN) solution that switches between centralized and distributed operational modes depending on network conditions, and evaluate this solution under a variety of network scenarios (e.g., link impairments or packet loss ratios) designed to assess its operational limits. The results show that the proposed solution substantially improved the aggregated throughput, particularly when control channel packet loss ratios increased, while only showing a slight increase in average latency (e.g., 28% throughput improvement for 20% control packet losses). This enables network operation in hard conditions under which a canonical centralized SDN control would result in a nonoperational network.

scholarly journals Performance Analysis on Multiple Device Connections of Small Office Home Office Network

2021 ◽  
Vol 18 (4(Suppl.)) ◽  
pp. 1457
Author(s):  
Muhamad Nur Ashaari ◽  
Murizah Kassim ◽  
Ruhani Ab. Rahman ◽  
Abd Razak Mahmud
Keyword(s):  
Performance Analysis ◽  
Packet Loss ◽  
High Speed ◽  
Network Performance ◽  
Network Services ◽  
Quality Of Services ◽  
Home Office ◽  
Internet Connections ◽  
The Impact

Malaysia has been supported by one of the high-speed fiber internet connections called TM UniFi. TM UniFi is very familiar to be used as a medium to apply Small Office Home Office (SOHO) concept due to the COVID-19 pandemic. Most of the communication vendors offer varieties of network services to fulfill customers' needs and satisfaction during the pandemic. Quality of Services is queried by most users by the fact of increased on users from time to time. Therefore, it is crucial to know the network performance contrary to the number of devices connected to the TM UniFi network. The main objective of this research is to analyze TM UniFi performance with the impact of multiple device connections or users' services. The study was conducted to analyze the QoS on its traffic, packets transfer, RTT, latency, and throughput. Wireshark simulation program has been used as a network traffic capture where PCAP files have been analyzed by using PCAP Analyzer for Splunk. Traffic filtering has been enabled to capture selected traffic to measure network performance. The result shows that better network performance can be achieved if a smaller number of devices are connected at the same time.  The percentage of packet loss, RTT, latency is increased when more users connected at the same time. The throughput also shows a decrease for multi-device connections. Based on the analysis it can be concluded that TM UniFi still can provide good network services for the SOHO network environment and sufficient bandwidth despite the rapid user growth in Malaysia.

Path Reconstruction and Effective Routing with Advanced Congestion Diversity in Wireless Adhoc Networks

2018 ◽  
Vol 6 (9) ◽  
pp. 125
Author(s):  
O. Srinivasa Rao ◽  
K. Madhuri
Keyword(s):  
Packet Loss ◽  
Network Performance ◽  
Ad Hoc ◽  
Detection Accuracy ◽  
Malicious Nodes ◽  
Packet Losses ◽  
Packet Dropping ◽  
Insider Attack ◽  
Wireless Adhoc Networks ◽  
Block Based

Link error and malicious packet dropping are two sources for packet losses in multi-hop wireless ad hoc network. In this paper, while observing a sequence of packet losses in the network, we are interested in determining whether the losses are caused by link errors only, or by the combined effect of link errors and malicious drop. We are especially interested in the insider-attack case, whereby malicious nodes that are part of the route exploit their knowledge of the communication context to selectively drop a small amount of packets critical to the network performance. Because the packet dropping rate in this case is comparable to the channel error rate, conventional algorithms that are based on detecting the packet loss rate cannot achieve satisfactory detection accuracy. To improve the detection accuracy, we propose to exploit the correlations between lost packets. Furthermore, to ensure truthful calculation of these correlations, we develop a homomorphic linear authenticator (HLA) based public auditing architecture that allows the detector to verify the truthfulness of the packet loss information reported by nodes. This construction is privacy preserving, collusion proof, and incurs low communication and storage overheads. To reduce the computation overhead of the baseline scheme, a packet-block based mechanism is also proposed, which allows one to trade detection accuracy for lower computation complexity. Through extensive simulations, we verify that the proposed mechanisms achieve significantly better detection accuracy than conventional methods such as a maximum-likelihood based detection.

scholarly journals Latency-Based Dynamic Controller Assignment in Hybrid SDNs: Considering the Impact of Legacy Routers

2019 ◽  
Vol 11 (8) ◽  
pp. 168
Author(s):  
Jie Yuan ◽  
Erxia Li ◽  
Chaoqun Kang ◽  
Fangyuan Chang ◽  
Tingting Yuan ◽  
...  
Keyword(s):  
Packet Loss ◽  
Network Architecture ◽  
Loss Rate ◽  
Packet Loss Rate ◽  
Network Control ◽  
Dynamic Controller ◽  
Pass Through ◽  
The Impact ◽  
Assignment Scheme ◽  
Hybrid Sdn

Software-defined networking (SDN) is a modern network architecture, which separates the network control plane from the data plane. Considering the gradual migration from traditional networks to SDNs, the hybrid SDN, which consists of SDN-enabled devices and legacy devices, is an intermediate state. For wide-area hybrid SDNs, to guarantee the control performance, such as low latency, multi SDN controllers are usually needed to be deployed at different places. How to assign them to switches and partition the network into several control domains is a critical problem. For this problem, the control latency and the packet loss rate of control messages are important metrics, which have been considered in a lot of previous works. However, hybrid SDNs have their unique characters, which can affect the assignment scheme and have been ignored by previous studies. For example, control messages pass through Legacy Forwarding Devices (LFDs) in hybrid SDNs and cause more latency and packet loss rate for queuing compared with SDN-enabled Forwarding Devices (SFDs). In this paper, we propose a dynamic controller assignment scheme in hybrid SDNs, which is called the Legacy Based Assignment (LBA). This scheme can dynamically delegate each controller with a subset of SFDs in the hybrid SDNs, whose objective is to minimize average SFD-to-control latency. We performed some experiments compared with other schemes, which show that our scheme has a better performance in terms of the latency and the packet loss rate.

Self-Organization Activities in LTE-Advanced Networks

2014 ◽  
pp. 67-98
Author(s):  
Ali Diab ◽  
Andreas Mitschele-Thiel
Keyword(s):  
Network Performance ◽  
Cost Effective ◽  
Use Cases ◽  
Lte Networks ◽  
Lte Advanced ◽  
Network Operation ◽  
Research Questions ◽  
Effective Network ◽  
Essential Contribution ◽  
State Of Art

A major challenge in the context of LTE networks is a cost-effective network operation, which can be done by carefully controlling the network Operational Expenses (OPEX). Therefore, to minimize OPEX costs while optimizing network performance, Self-Organizing Network (SON) principles were proposed. These networks are the main focus of this chapter, which highlights the state of art and provides a comprehensive investigation of current research efforts in the field of SONs. A major contribution of the chapter is the handling of SON use cases, going through their challenges, solutions. and open research questions. The chapter also presents efforts to provide coordination frameworks between SON use cases and routines. An additional essential contribution of the chapter is the description of SON activities within 3GPP.

scholarly journals The Impact of Traffic Type and Node Mobility on an 802.16 Mobile WiMAX for Varying Network Sizes

2013 ◽  
Vol 5 (4) ◽  
pp. 63-80
Author(s):  
James K. Byeon ◽  
Nurul I. Sarkar ◽  
Jairo A. Gutiérrez
Keyword(s):  
Packet Loss ◽  
Response Times ◽  
Video Conferencing ◽  
Network Size ◽  
Mobile Wimax ◽  
Node Mobility ◽  
Large Network ◽  
Packet Losses ◽  
Type Node ◽  
The Impact

While WiMAX handoff characteristics and quality of service (QoS) provisioning have been explored by many network researchers, the effect of traffic type, node mobility and network size on WiMAX has not been fully explored yet. This paper therefore reports on a study of the impact of traffic type and node mobility on the performance of a typical mobile 802.16 WiMAX for varying network sizes. The authors consider small, medium and large network scenarios under four different traffic types (FTP, HTTP, VoIP and Videoconferencing) with node speeds of up to 90 km/hour. The authors developed an extensive simulation model using OPNET Modeler to measure network throughputs, FTP response times, HTTP object and page response times, VoIP jitter, and Video conferencing end-to-end delays. Results obtained show that packet delays of less than one second are maintained regardless of increased node speeds. Packet loss ratios for VoIP and video conferencing are irregularly high and increase with network traffic. Another observation is that the average throughput of video conferencing and m-VoIP is decreased and packet loss ratio is irregularly increased causing loss of connection. As expected, both FTP and HTTP traffic are transmitted well over WiMAX because they can tolerate a certain amount of delays. However, the transmission of both m-VoIP and video conferencing packets suffered high packet losses. The results reported in this paper provide some insights into the performance of 802.16 WiMAX with respect to the traffic type, network size and node mobility on system performance.

scholarly journals Man-In-The-Middle Attacks in Vehicular Ad-Hoc Networks: Evaluating the Impact of Attackers’ Strategies

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4040 ◽  
Author(s):  
Farhan Ahmad ◽  
Asma Adnane ◽  
Virginia Franqueira ◽  
Fatih Kurugollu ◽  
Lu Liu
Keyword(s):  
Intelligent Transportation Systems ◽  
Network Performance ◽  
Traffic Accidents ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Transportation Systems ◽  
Packet Losses ◽  
Traffic Efficiency ◽  
Man In The Middle ◽  
The Impact

Vehicular Ad-Hoc Network (VANET), a vital component of Intelligent Transportation Systems (ITS) technology, relies on communication between dynamically connected vehicles and static Road Side Units (RSU) to offer various applications (e.g., collision avoidance alerts, steep-curve warnings and infotainment). VANET has a massive potential to improve traffic efficiency, and road safety by exchanging critical information between nodes (vehicles and RSU), thus reducing the likelihood of traffic accidents. However, this communication between nodes is subject to a variety of attacks, such as Man-In-The-Middle (MITM) attacks which represent a major risk in VANET. It happens when a malicious node intercepts or tampers with messages exchanged between legitimate nodes. In this paper, we studied the impact on network performance of different strategies which attackers can adopt to launch MITM attacks in VANET, such as fleet or random strategies. In particular, we focus on three goals of MITM attacks—message delayed, message dropped and message tampered. The simulation results indicate that these attacks have a severe influence on the legitimate nodes in VANET as the network experience high number of compromised messages, high end-to-end delays and preeminent packet losses.

scholarly journals Modelling and Performance Analysis of OpenFlow Switches in Software-Defined Networking

2021 ◽  
Author(s):  
◽  
Deepak Singh
Keyword(s):  
Packet Loss ◽  
Network Performance ◽  
Queueing Model ◽  
Buffer Dimensioning ◽  
Buffer Sharing ◽  
And Performance ◽  
The Impact ◽  
Internal Buffer ◽  
Shared Buffer ◽  
Selection Of

<p>Software-Defined-Networking (SDN) simplifies the configuration complexity in the computer communication network by decoupling the control plane from the data plane in a switch. In SDN, the switch has the data plane only and is configured by the logically centralised controller which simplifies the forwarding of packets in the network. However, an SDN switch is sensitive to delay and loss of packets which significantly affects the network performance.  This thesis uses queueing theory to conduct modelling and performance analysis of OpenFlow-based SDN switches. OpenFlow is the de-facto protocol for communication between an SDN switch and the controller. Using queueing theory, three aspects of packet processing in an SDN switch are explored. First, the existing research has primarily modelled the output buffer of an SDN switch using two buffer sharing mechanisms: the single shared buffer and the priority buffer. However, the effect of buffer dimensioning in these buffer sharing mechanisms has not been investigated. Buffer dimensioning helps in determining the minimum buffer capacity for a desired loss probability. The research in this thesis shows that the use of priority buffer in an SDN switch reduces the time to update flow tables than the shared buffer but at the cost of a higher buffer capacity.  Second, much of the existing research has not investigated the impact of internal buffering of data packets whereby a fraction of a data packet header is sent to the controller instead of an entire data packet. To investigate the impact of internal buffering, the queueing model for an SDN switch with the internal buffer is developed. The investigation shows that at the time of congestion, the internal buffer in an SDN switch improves the network performance with lower delay and lower packet loss.  Finally, existing research has focused on a software switch in SDN and very little research has studied the performance of a hardware switch. To characterise the performance of SDN-based hardware and software switches and identify the tradeoffs between them, a unified queueing model has been developed. The unified queueing model is an analytical tool for network engineers to predict delay and packet loss in their SDN deployments. The analysis shows the benefits of a hardware switch over a software switch. These benefits are lower delay and lower packet loss. However, the increasing involvement of the controller reduces the benefit of using a hardware switch, i.e. forwarding packets at the line speed rate.  This research guides network designers and analysts in the selection of the shared or buffer model for an SDN switch for their desired Quality of Service (QoS). Furthermore, the developed queueing model for an SDN switch with the internal buffer studies the impact of internal buffering in an SDN switch. Finally, the unified queueing model helps in the selection of a software or hardware switch in SDN.</p>

scholarly journals Modelling and Performance Analysis of OpenFlow Switches in Software-Defined Networking

2021 ◽  
Author(s):  
◽  
Deepak Singh
Keyword(s):  
Packet Loss ◽  
Network Performance ◽  
Queueing Model ◽  
Buffer Dimensioning ◽  
Buffer Sharing ◽  
And Performance ◽  
The Impact ◽  
Internal Buffer ◽  
Shared Buffer ◽  
Selection Of

<p>Software-Defined-Networking (SDN) simplifies the configuration complexity in the computer communication network by decoupling the control plane from the data plane in a switch. In SDN, the switch has the data plane only and is configured by the logically centralised controller which simplifies the forwarding of packets in the network. However, an SDN switch is sensitive to delay and loss of packets which significantly affects the network performance.  This thesis uses queueing theory to conduct modelling and performance analysis of OpenFlow-based SDN switches. OpenFlow is the de-facto protocol for communication between an SDN switch and the controller. Using queueing theory, three aspects of packet processing in an SDN switch are explored. First, the existing research has primarily modelled the output buffer of an SDN switch using two buffer sharing mechanisms: the single shared buffer and the priority buffer. However, the effect of buffer dimensioning in these buffer sharing mechanisms has not been investigated. Buffer dimensioning helps in determining the minimum buffer capacity for a desired loss probability. The research in this thesis shows that the use of priority buffer in an SDN switch reduces the time to update flow tables than the shared buffer but at the cost of a higher buffer capacity.  Second, much of the existing research has not investigated the impact of internal buffering of data packets whereby a fraction of a data packet header is sent to the controller instead of an entire data packet. To investigate the impact of internal buffering, the queueing model for an SDN switch with the internal buffer is developed. The investigation shows that at the time of congestion, the internal buffer in an SDN switch improves the network performance with lower delay and lower packet loss.  Finally, existing research has focused on a software switch in SDN and very little research has studied the performance of a hardware switch. To characterise the performance of SDN-based hardware and software switches and identify the tradeoffs between them, a unified queueing model has been developed. The unified queueing model is an analytical tool for network engineers to predict delay and packet loss in their SDN deployments. The analysis shows the benefits of a hardware switch over a software switch. These benefits are lower delay and lower packet loss. However, the increasing involvement of the controller reduces the benefit of using a hardware switch, i.e. forwarding packets at the line speed rate.  This research guides network designers and analysts in the selection of the shared or buffer model for an SDN switch for their desired Quality of Service (QoS). Furthermore, the developed queueing model for an SDN switch with the internal buffer studies the impact of internal buffering in an SDN switch. Finally, the unified queueing model helps in the selection of a software or hardware switch in SDN.</p>

scholarly journals Network Performance Evaluation of Abis Interface over DVB-S2 in the GSM over Satellite Network

2010 ◽  
Vol 2010 ◽  
pp. 1-8
Author(s):  
S. B. Musabekov ◽  
P. K. Srinivasan ◽  
A. S. Durai ◽  
R. R. Ibraimov
Keyword(s):  
Network Performance ◽  
Cost Effective ◽  
Base Station ◽  
Satellite Network ◽  
Channel Network ◽  
Network Availability ◽  
Link Budget ◽  
Base Transceiver Station ◽  
Gsm Network ◽  
The Impact

This paper deals with establishing a GSM link over Satellite. Abis interface, which is defined between Base Transceiver Station (BTS) and Base Station Controller (BSC), in a GSM network is considered here to be routed over the Satellite. The satellite link enables a quick and cost-effective GSM link in meagerly populated areas. A different scenario comparison was done to understand the impact of Satellite environment on network availability comparing to terrestrial scenario. We have implemented an Abis interface over DVB S2 in NS2 and evaluated the performance over the high delay and loss satellite channel. Network performance was evaluated with respect to Satellite channel delay and DVB S2 encapsulation efficiency under different amount of user traffic and compared with the terrestrial scenario. The results clearly showed an increased amount of SDCCH and TCH channels required in the case of satellite scenario for the same amount of traffic in comparison to conventional terrestrial scenario. We have optimized the parameters based on the simulation results. Link budget estimation considering DVB-S2 platform was done to find satellite bandwidth and cost requirements for different network setups.

Regulatory and sustainability initiatives lead to improved polyaminopolyamide epichlorohydrin (PAE) wet-strength resins and paper products

TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 519-532 ◽  
Author(s):  
Mark Crisp ◽  
Richard Riehle
Keyword(s):  
Health And Safety ◽  
Cost Effective ◽  
Worker Safety ◽  
Regulatory Requirements ◽  
Wet Strength ◽  
The Past ◽  
Consumer Safety ◽  
Federal Institute ◽  
Sustainability Initiatives ◽  
The Impact

Polyaminopolyamide-epichlorohydrin (PAE) resins are the predominant commercial products used to manufacture wet-strengthened paper products for grades requiring wet-strength permanence. Since their development in the late 1950s, the first generation (G1) resins have proven to be one of the most cost-effective technologies available to provide wet strength to paper. Throughout the past three decades, regulatory directives and sustainability initiatives from various organizations have driven the development of cleaner and safer PAE resins and paper products. Early efforts in this area focused on improving worker safety and reducing the impact of PAE resins on the environment. These efforts led to the development of resins containing significantly reduced levels of 1,3-dichloro-2-propanol (1,3-DCP) and 3-monochloropropane-1,2-diol (3-MCPD), potentially carcinogenic byproducts formed during the manufacturing process of PAE resins. As the levels of these byproducts decreased, the environmental, health, and safety (EH&S) profile of PAE resins and paper products improved. Recent initiatives from major retailers are focusing on product ingredient transparency and quality, thus encouraging the development of safer product formulations while maintaining performance. PAE resin research over the past 20 years has been directed toward regulatory requirements to improve consumer safety and minimize exposure to potentially carcinogenic materials found in various paper products. One of the best known regulatory requirements is the recommendations of the German Federal Institute for Risk Assessment (BfR), which defines the levels of 1,3-DCP and 3-MCPD that can be extracted by water from various food contact grades of paper. These criteria led to the development of third generation (G3) products that contain very low levels of 1,3-DCP (typically <10 parts per million in the as-received/delivered resin). This paper outlines the PAE resin chemical contributors to adsorbable organic halogens and 3-MCPD in paper and provides recommendations for the use of each PAE resin product generation (G1, G1.5, G2, G2.5, and G3).

Sign in / Sign up

Export Citation Format

Share Document