Because of the arrival of local 5G, real-time services using videos through wireless networks, such as remote surveillance and teleoperation, have attracted considerable attention. However, drastic ...changes in available bandwidth (AB) that are caused by moving obstacles or rapid changes in radio traffic pose challenges in providing a guaranteed quality of video streams. Robust video streams without disconnection over wireless networks necessitate an estimation of the AB reflected by the changing wireless environment and controlling of the video quality by the AB. For conventional studies, the AB is rapidly calculated using a table that maps an indicator of wireless-link quality to the AB. However, because the fixed table does not reflect changes in radio traffic, there are discrepancies between the estimated and real AB. Therefore, to precisely estimate the AB that reflects the changing wireless environment, we propose a hybrid calibration method, comprising long-term and short-term calibrations in this study. The long-term calibration determines invariant parameters of the table, which map the received signal strength indicator (RSSI) to the AB (RSSI-AB table). The short-term calibration enables a variant parameter to follow changes in traffic from other terminals. For experimentally evaluating the proposed method, a real Wi-Fi network scenario with a video transmission connection was implemented and traffic from another terminal connected via the same access point was added. Based on the mean absolute logarithmic deviation, the results showed that the proposed method was 1.23 times more accurate than the conventional method.
Estimation of available bandwidth for ad hoc networks has always been open and active challenge for the researchers. A lot of literature is proposed in the last 20 years to evaluate the residual ...bandwidth. The main objective of the work being admission of new flow in the network with the constraint that any existing current transmission is not affected. One of the prime factors affecting the estimation process is the collision among packets. These collisions trigger the backoff algorithm that leads to wastage of the usable bandwidth. Although a lot of state of art solutions were proposed, but they suffer from various flaws and shortcoming. Other factor contributing to the inaccuracy in existing solution is the mobility of nodes. Node mobility leads to instability of links leading to data losses and delay which impact the bandwidth. The current paper proposes an analytical approach named Analytical Available Bandwidth Estimation Including Mobility (AABWM) to estimate ABW on a link. The major contributions of the proposed work are: i) it uses mathematical models based on renewal theory to calculate the collision probability of data packets which makes the process simple and accurate, ii) consideration of mobility under 3-D space to predict the link failure and provides an accurate admission control. Extensive simulations in NS-2 are carried out to compare the performance of the proposed model against the existing solutions.
Quality of Service provisioning for real-time multimedia applications is largely determined by a network’s available bandwidth. Until now, there is no standard method for estimating bandwidth on ...wireless networks. Therefore, in this study, a mathematical model called Modified Passive Available Bandwidth Estimation (MPABE) was developed to estimate the available bandwidth passively on a Distributed Coordination Function (DCF) wireless network on the IEEE 802.11 protocol. The mathematical model developed was a modification of three existing mathematical models, namely Available Bandwidth Estimation (ABE), Cognitive Passive Estimation of Available Bandwidth V2 (cPEAB-V2), and Passive Available Bandwidth Estimation (PABE). The proposed mathematical model gave emphasis on what will be faced to estimate available bandwidth and will help in building strategies to estimate available bandwidth on IEEE 802.11. The developed mathematical model consisted of idle period synchronisation between sender and receiver, the overhead probability occurring in the Medium Access Control (MAC) layer, as well as the successful packet transmission probability. Successful packet transmission was influenced by three variables, namely the packet collision probability caused by a number of neighbouring nodes, the packet collision probability caused by traffic from hidden nodes, and the packet error probability. The proposed mathematical model was tested by comparing it with other relevant mathematical models. The performance of the four mathematical models was compared with the actual bandwidth. Using a series of experiments that have been performed, it was found that the proposed mathematical model is approximately 26% more accurate than ABE, 36% more accurate than cPEABV2, and 32% more accurate than PABE.
In the field of network monitoring and measurement, the efficiency and accuracy of the adopted tools is strongly dependent on (i) structural and dynamic characteristics of the network scenario under ...measurement and (ii) on manual fine tuning of the involved parameters. This is, for example, the case of the end-to-end available bandwidth estimation, in which the constraints of the measurement stage vary according to the use of the final results. In this work, we present UANM (unified architecture for network measurement), a novel measurement infrastructure for the automatic management of measurement stages, tailored to the end-to-end available bandwidth estimation tools. We describe in detail its architecture, illustrating the features we introduced to mitigate the problems affecting available bandwidth estimation in heterogeneous scenarios. To provide evidences of UANM benefits, we present an experimental validation in three selected scenarios deployed over a real network testbed to (i) quantify the overhead introduced by the use of UANM, (ii) show how UANM is able to alleviate the interferences among concurrent measurements, and (iii) illustrate how UANM is capable to provide more accurate results thanks to the knowledge of the network environment. Finally, for the first time in literature, we provide a “fair comparison” of eight available bandwidth estimations tools in terms of accuracy, probing time, and intrusiveness.
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This paper presents a unique probing scheme, a rate adjustment algorithm, and a modified excursion detection algorithm (EDA) for estimating the available bandwidth (ABW) of an end-to-end network path ...more accurately and less intrusively. The proposed algorithm is based on the well-known concept of self-induced congestion and it features a unique probing train structure in which there is a region where packets are sampled more frequently than in other regions. This high-density region enables our algorithm to find the turning point more accurately. When the dynamic ABW is outside of this region, we readjust the lower rate and upper rate of the packet stream to fit the dynamic ABW into that region. We appropriately adjust the range between the lower rate and the upper rate using spread factors, which enables us to keep the number of packets low, and we are thus able to measure the ABW less intrusively. Finally, to detect the ABW from the one-way queuing delay, we present a modified EDA from PathChirps' original EDA to better deal with sudden increase and decrease in queuing delays due to cross traffic burstiness. For the experiments, an Android OS-based device was used to measure the ABW over a commercial 4G/LTE mobile network of a Japanese mobile operator, as well, as real testbed measurements were conducted over fixed and WLAN network. Simulations and experimental results show that our algorithm can achieve ABW estimations in real time and outperforms other stat-of-the-art measurement algorithms in terms of accuracy, intrusiveness, and convergence time.
Available Bandwidth Estimation (ABE) has been the subject of several studies in recent years. ABE tools based on the PRM approach have been the primary choice for production environments since they ...are more suitable for applications that are far from users (e.g., Cloud applications). At the same time, the 802.11n wireless network standard has been increasingly used in companies and homes. However, the 802.11n introduced significant changes to improve efficiency such as Frame Aggregation (FA) and the Channel Bonding (CB), which directly influence the accuracy of ABE techniques. Therefore, this work aims to provide a solution that reduces the impact of the new 802.11n arrangements in ABE. For this, we initially performed experiments on a testbed to assess how much these 802.11n MAC layer factors influence the estimates of four ABE tools: ASSOLO, PTR, PathChirp, and YAZ. Results showed that YAZ achieved the best efficiency. Nevertheless, its accuracy is significantly affected in FA-enabled scenarios. Then, we performed an indepth analysis of YAZ aiming to identify the causes of that problem. Finally, we proposed and evaluated the YAZ++, a tool that implements a new technique to improve ABE accuracy in FA scenarios. Results showed an improvement in the estimated values.
Available Bandwidth Estimation Techniques and Tools (ABETTs) have recently been envisioned as a supporting mechanism in areas such as compliance of service level agreements, network management, ...traffic engineering and real-time resource provisioning, flow and congestion control, construction of overlay networks, fast detection of failures and network attacks, and admission control. However, it is unknown whether current ABETTs can run efficiently in any type of network, under different network conditions, and whether they can provide available bandwidth estimates at the timescales needed by these applications. This article includes a performance evaluation of Pathload, Pathchirp, Spruce, IGI, and Abing in a low cost and flexible test bed. The evaluation includes scenarios and conditions not evaluated before, such as varying the packet loss rate and the propagation delays of the links, the amount of cross-traffic, the capacity of the links, and the cross-traffic packet size. The results demonstrate that ABETTs are far from being ready to be applied in all these applications and scenarios. In addition, the article clearly indicates those aspects that need further research and which ABETTs are the best candidates for specific applications and environments.
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In 802.11 wireless network, a large number of multimedia applications are emerging. Accurate end-to-end bandwidth estimation techniques can help these applications adjust their behavior accordingly, ...such as stream’s bitrate adaptation, to improve quality of service. However, most current bandwidth estimation techniques are designed for wired networks that have high intrusiveness and consume long convergence time, which cannot be applied in resource-limited wireless network. In this article, we present a novel bandwidth estimation tool for IEEE 802.11 wireless network, which only needs to be deployed in one end of the end-to-end path and estimate available bandwidth based on round-trip-time measurements with low intrusiveness and short convergence time. We compare our tool with another state-of-the-art tool on an IEEE 802.11 wireless testbed, and the experimental results show that our tool has higher accuracy.
PurposeQuality communication is a big challenge in mobile ad hoc networks because of a restricted environment for mobile devices, bandwidth-constrained radio connections, random mobility of connected ...devices, etc. High-quality communication through wireless links mainly depends on available bandwidth, link stability, energy of nodes, etc. Many researchers proposed stability and link quality methods to improve these issues, but they still require optimization. This study aims to contribute towards better quality communication in temporarily formed networks. The authors propose the stable and bandwidth aware dynamic routing (SBADR) protocol with the aim to provide an efficient, stable path with sufficient bandwidth and enough energy hold nodes for all types of quality of service (QoS) data communication.Design/methodology/approachThe proposal made in this work used received signal strength from the media access control (MAC) layer to estimate the stability of the radio connection. The proposed path stability model combines the stability of the individual link to compute path stability. The amount of bandwidth available for communication at a specific time on a link is defined as the available link bandwidth that is understood as the maximum throughput of that link. Bandwidth as a QoS parameter ensures high-quality communication for every application in such a network. One other improvement, towards quality data transmission, is made by incorporating residual energies of communicating and receiving nodes in the calculation of available link bandwidth.FindingsCommunication quality in mobile ad hoc network (MANET) does not depend on a single parameter such as bandwidth, energy, path stability, etc. To address and enhance quality communication, this paper focused on high impact factors, such as path stability, available link bandwidth and energy of nodes. The performance of SBADR is evaluated on the network simulator and compared with that of other routing protocols, i.e. route stability based QoS routing (RSQR), route stability based ad-hoc on-demand distance vector (RSAODV) and Ad-hoc on-demand distance vector (AODV). Experimental outcomes show that SBADR significantly enhanced network performance in terms of throughput, packet delivery ratio (PDR) and normalized control overhead (NCO). Performance shows that SBADR is suitable for any application of MANET having random and high mobility.Research limitations/implicationsQoS in MANET is a challenging task. To achieve high-quality communication, the authors worked on multiple network parameters, i.e. path stability, available link bandwidth and energy of mobile nodes. The performance of the proposed routing protocol named SBADR is evaluated by a network simulator and compared with that of other routing protocols. Statistical analysis done on results proves significant enhancement in network performance. SBADR is suitable for applications of MANET having random and high mobility. It is also efficient for applications having a requirement of high throughput.Practical implicationsSBADR shows a significant enhancement in received data bytes, which are 1,709, 788 and 326 more in comparison of AODV, RSAODV and RSQR, respectively. PDR increased by 21.27%, 12.1%, 4.15%, and NCO decreased by 9.67%, 5.93%, 2.8% in comparison of AODV, RSAODV and RSQR, respectively.Social implicationsOutcomes show SBADR will perform better with applications of MANET such as disaster recovery, city tours, university or hospital networks, etc. SBADR is suitable for every application of MANET having random and high mobility.Originality/valueThis is to certify that the reported work in the paper entitled “SBADR: stable and bandwidth aware dynamic routing protocol for mobile ad hoc network” is an original one and has not been submitted for publication elsewhere. The authors further certify that proper citations to the previously reported work have been given and no data/tables/figures have been quoted verbatim from the other publications without giving due acknowledgment and without permission of the author(s).
Service prioritization among different traffic classes is an important goal for the Internet. Conventional approaches to solving this problem consider the existing best-effort class as the ...low-priority class, and attempt to develop mechanisms that provide "better-than-best-effort" service. In this paper, we explore the opposite approach, and devise a new distributed algorithm to realize a low-priority service (as compared to the existing best effort) from the network endpoints. To this end, we develop TCP Low Priority (TCP-LP), a distributed algorithm whose goal is to utilize only the excess network bandwidth as compared to the "fair share" of bandwidth as targeted by TCP. The key mechanisms unique to TCP-LP congestion control are the use of one-way packet delays for early congestion indications and a TCP-transparent congestion avoidance policy. The results of our simulation and Internet experiments show that: 1) TCP-LP is largely non-intrusive to TCP traffic; 2) both single and aggregate TCP-LP flows are able to successfully utilize excess network bandwidth; moreover, multiple TCP-LP flows share excess bandwidth fairly; 3) substantial amounts of excess bandwidth are available to the low-priority class, even in the presence of "greedy" TCP flows; 4) the response times of web connections in the best-effort class decrease by up to 90% when long-lived bulk data transfers use TCP-LP rather than TCP; 5) despite their low-priority nature, TCP-LP flows are able to utilize significant amounts of available bandwidth in a wide-area network environment
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