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The IEEE Audio Video Bridging (AVB) technology is nowadays under consideration in several automation domains, such as, automotive, avionics, and industrial communications. AVB offers several benefits, such as open specifications, the existence of multiple providers of electronic components, and the real-time support, as AVB provides bounded latency to real-time traffic classes. In addition to the above mentioned properties, in the automotive domain, comparing with the existing in-vehicle networks, AVB offers significant advantages in terms of high bandwidth, significant reduction of cabling costs, thickness and weight, while meeting the challenging EMC/EMI requirements. Recently, an improvement of the AVB protocol, called the AVB ST, was proposed in the literature, which allows for supporting scheduled traffic, i.e., a class of time-sensitive traffic that requires time-driven transmission and low latency. In this paper, we present a schedulability analysis for the real-time traffic crossing through the AVB ST network. In addition, we formally prove that, if the bandwidth in the network is allocated according to the AVB standard, the schedulability test based on response time analysis will fail for most cases even if, in reality, these cases are schedulable. In order to provide guarantees based on analysis test a bandwidth over-reservation is required. In this paper, we propose a solution to obtain a minimized bandwidth over-reservation. To the best of our knowledge, this is the first attempt to formally spot the limitation and to propose a solution for overcoming it. The proposed analysis is applied to both the AVB standard and the AVB ST. The analysis results are compared with the results of several simulative assessments, obtained using OMNeT++, on both automotive and industrial case studies. The comparison between the results of the analysis and the simulation ones shows the effectiveness of the analysis proposed in this work.

In this paper we present the development experience of implementing a protocol supporting Quality of Service guarantees. We believe that this work is of interest to researchers and engineers who are interested in real-life experience with such a protocol on a high-performance commercial router. The emphasis of this paper is the study of queueing algorithms intended to support QoS guarantees in a mixed traffic environment. We present practical results that demonstrate the feasibility as well as some limitations of the idea of mixing real-time traffic with traditional data traffic in a commercial router.

Mobile Ad hoc networks (MANETs) are collections of wireless mobile nodes dynamically reconfiguring and collectively forming a temporary network. These types of networks assume existence of no fixed infrastructure and are often useful in battle-field tactical operations or emergency search-and-rescue type of operations where fixed infrastructure is neither feasible nor practical. They also find use in ad hoc conferences, campus networks and commercial recreational applications carrying multimedia traffic. All of the above applications of MANETs require guaranteed levels of performance as experienced by the end-user. This paper focuses on key challenges in provisioning predetermined levels of such Quality of Service (QoS). It also identifies functional areas where QoS models are currently defined and used. Evolving functional areas where performance and QoS provisioning may be applied are also identified and some suggestions are provided for further research in this area. Although each of the above functional areas have been discussed separately in recent research studies, since these QoS functional areas are highly correlated and interdependent, a comprehensive and comparative analysis of these areas and their interrelationships is desired. In this paper we have attempted to provide such an overview., {"references":["Abdrabou A, Zhuang W (2006) A position-based QoS routing scheme\nfor UWB mobile ad hoc networks. IEEE J. Select. Areas Commun.\n24:850-856.","Ahn G S, Campbell A T, Lee S B, Zhang X (1999) INSIGNIA. Internet\nDraft. comet. columbia.edujinsigniajdraft-ietf-manet-insignia-01.txt\nAccessed 18 March 2008.","Ahn G S, Campbell A T, Veres A, Sun L H (2002) Supporting service\ndifferentiation for real-time and best effort traffic in stateless Wireless\nAd Hoc Networks (SWAN), IEEE Transactions on Mobile Computing 1\n(3): 192-207.","Badis H, Agha K A (2005) QOLSR: QoS routing for ad hoc wireless\nnetworks using OLSR. 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In WMN, at the time of network consignment and bandwidth registration, the active network consignment method did not take into consideration the intrusion, congestion load and bandwidth necessities as a whole. The significance centred bandwidth registration methods result in famishment of slightest significance congestion. Hence in this paper, we propose a Joint Channel Assignment and Bandwidth Reservation using Improved FireFly Algorithm (IFA) in WMN. Initially the priority of each node is determined based on the channel usage, future interference and link congestion probability metrics. The bandwidth is allocated straight, comparative to the nodule significance and entire quantity of congestion movements incomplete on the demanded nodule. For channel assignment and path selection, the improved FireFly Algorithm (IFA) is used. The objective function of IFA is determined in terms of link capacity, interference and flow conservation constraints. Then the channels and the path which minimize the objective function are selected by applying IFA. By simulation results we show that the proposed technique minimizes the traffic and enhances the channel efficiency.

International audience; Hardware platforms for real-time embedded systems are evolving towards heterogeneous architectures comprising different types of processing cores and dedicated hardware accelerators, which can be implemented on silicon or dynamically deployed on FPGA fabric. Such accelerators typically access a shared memory to exchange a significant amount of data with other processing elements. Existing COTS solutions focus on maximizing the overall throughput of the system, rather than guaranteeing the timing constraints of individual hardware accelerators. This paper presents the AXI budgeting unit (ABU), a hardware-based solution to implement a bandwidth reservation mechanism on top of the AMBA AXI standard infrastructure for hardware accelerators deployed on FPGAs. An accurate and tractable model, as well as the corresponding analysis, are also proposed to bound the response time of hardware accelerators in the presence of ABUs, in order to verify whether they can complete before their deadlines. Finally, a set of experiments are reported to evaluate the proposed approach on a state-of-the-art platform, namely the Zynq-7020 by Xilinx. The resource consumption of the ABU has been quantified to be less than 1% of the total FPGA resources of the Zynq-7020.

With the emergency of more and more video applications, the problem of providing differentiated Quality of Service (QoS) for various kinds of streams should be solved. DiffServ was proposed to balance transmission guarantee of video and data streams. Existing studies focused on the promotion of video receiving quality by allocating excess resources. In this paper we propose an optimal bandwidth reservation mechanism, aiming at proper amount of bandwidth reservation and good video transmission performance. This mechanism tries to find a moderate reservation according to the video characteristics and buffer size of forwarding routers. Various video sequences and different buffer sizes are employed in the performance evaluation experiments and simulation results verify that (1) Proposed mechanism show its adaptability to data rate, data rate variation and continuous burst of the streaming video. (2) Proposed mechanism presents good performance under various buffer sizes. (3) The amount of bandwidth reservation, which is determined by the streaming video and buffer size of forwarding routers, is moderate to ensure video receiving quality.

International audience; To support mixed-criticality applications, the AFDXmay integrate multiple traffic classes: Safety-Critical Traffic (SCT) with hard real-time constraints, Rate-Constrained (RC) traffic requiring bounded latencies and Best Effort (BE) traffic with no delivery constraints. These traffic classes are managed based on a Non-Preemptive Strict Priority (NP-SP) Scheduler, where the highest priority traffic (SCT) is shaped with a Burst Limiting Shaper (BLS). The latter has been defined by the Time Sensitive Networking (TSN) task group to limit the impact of high priority flows on lower priority ones. This paper proposestwo bandwidth reservation methods for BLS shapers in AFDXnetworks. The proposed methods are evaluated on a realisticAFDX configuration. Results show their efficiency to noticeablyenhance the RC delay bounds and the SCT schedulability, incomparison to an intuitive method.

Call admission control (CAC) schemes play a critical role in providing quality-of-service (QoS) guarantees for various classes of traffic with diverse QoS requirements in IEEE 802.16e networks. The dynamic CAC and bandwidth reservation scheme is one of the current schemes that simultaneously provides efficient utilization of network resources and guarantees QoS for admitted connections. However, its admission criteria starved high and low service classes due to its linear adaptation policy to accommodate more users into the network under moderate-to-heavy traffic load conditions. Its adaptive threshold for handoff connections is adjusted based on the arrival of new and handoff connections, that results in a waste of resources when the new and handoff connection arrival rate occurs frequently. In this paper, a new CAC scheme for Mobile WiMAX networks is proposed to prevent starvation of service classes and enhance the efficient utilization of network resources. The scheme determines a new admission criteria based on a scheduling service class. In the admission criteria, bandwidth degradation policy is used to admit more users when there is no available bandwidth to admit a more users. The adaptive threshold has been introduced dynamically to adjust the quantity of reserved bandwidth for handoff connections based on the traffic intensity of handoff requests. In addition, an analytical model for the proposed scheme is also developed. Extensive simulation experiments have been conducted to evaluate the performance of our proposed approach. The simulation results illustrate that the proposed scheme significantly improves the network efficiency compared to other schemes in terms of accepting more connections into the network and assuring QoS for all service classes. The numerical results have shown similar performance to the simulation results.

Recently, cloud computing has become a promising distributed processing paradigm to deploy various kinds of non-trivial applications. In those applications, most of them are considered data-intensive and therefore require the cloud system to provide massive storage space as well as desirable I/O performance. As a result, virtual disk technique has been widely applied in many real-world platforms to meet the requirements of these applications. Therefore, how to efficiently allocate the virtual disk bandwidth has become an important issue that needs to be addressed. In this paper, we present a novel virtual disk bandwidth allocation framework, in which a set of virtual bandwidth brokers are introduced to make allocation decisions by playing two game models. Theoretical analysis and solution are presented to prove the effectiveness of the proposed game models. Extensive experiments are conducted on a real-world cloud platform, and the results indicate that the proposed framework can significantly improve the utilisation of virtual disk bandwidth comparing with other existing approaches.

In this paper, we study the performance of the Multiple Fractional Channel Reservation (MFCR) policy, which is a bandwidth reservation policy that allows the reservation of real (not integer) number of channels in order to favor calls of high channel (bandwidth) requirements. We consider a link of fixed capacity that accommodates Poisson arriving calls of different service-classes with different bandwidth-per-call requirements. Calls compete for the available bandwidth under the MFCR policy. To determine call blocking probabilities, we propose approximate but recursive formulas based on the notion of reserve transition rates. The accuracy of the proposed method is verified through simulation.

To meet the various requirements of cloud computing users, research on guaranteeing Quality of Service (QoS) is gaining widespread attention in the field of cloud computing. However, as cloud computing platforms adopt virtualization as an enabling technology, it becomes challenging to distribute system resources to each user according to the diverse requirements. Although ample research has been conducted in order to meet QoS requirements, the proposed solutions lack simultaneous support for multiple policies, degrade the aggregated throughput of network resources, and incur CPU overhead. In this paper, we propose a new mechanism, called ANCS (Advanced Network Credit Scheduler), to guarantee QoS through dynamic allocation of network resources in virtualization. To meet the various network demands of cloud users, ANCS aims to concurrently provide multiple performance policies; these include weight-based proportional sharing, minimum bandwidth reservation, and maximum bandwidth limitation. In addition, ANCS develops an efficient work-conserving scheduling method for maximizing network resource utilization. Finally, ANCS can achieve low CPU overhead via its lightweight design, which is important for practical deployment.

Cellular IP network deals with micro mobility of the mobile devices. An important challenge in wireless communication, especially in cellular IP based network, is to provide good Quality of Service (QoS) to the users in general and to the real-time users (users involved in the exchange of real-time packets) in particular. Reserving bandwidth for real time traffic to minimize the connection drop (an important parameter) is an activity often used in Cellular IP network. Particle Swarm Optimization (PSO) algorithm simulates the social behavior of a swarm or flock to optimize some characteristic parameter. PSO is effectively used to solve many hard optimization problems. The work, in this paper, proposes an on demand bandwidth reservation scheme to improve Connection Dropping Probability (CDP) in cellular IP network by employing PSO. The swarm, in the model, consists of the available bandwidth in the seven cells of the cellular IP network. The anytime bandwidth demand for real-time users is satisfied by the available bandwidth of the swarm. The algorithm, used in the model, searches for the availability of the bandwidth and reserves it in the central cell of the swarm. Eventually, it will allocate it on demand to the cell that requires it. Simulation experiments reveal the efficacy of the model.

This paper presents an advanced bandwidth reservation technique to improve Quality of Service (QoS) by reducing the forced call termination during handoff. One solution to ensure continuity of on-going calls and reduce the forced call termination during handoff is to predict Mobile Station (MS) trajectory and do resource reservation in advance. So, we propose a new scheme that uses an accurate mobility prediction algorithm to predict MS next location and uses this data in bandwidth reservation scheme to improve QoS. The performance of the algorithm is evaluated via simulations. The simulation results show that our algorithm reduces handoff call drop rate without over reserving the resources hence it improves bandwidth utilization and reduces new call blocking rate.

Media production generally requires many geographically distributed actors (e.g., production houses, broadcasters, advertisers) to exchange huge amounts of raw video and audio data. Traditional distribution techniques, such as dedicated point-to-point optical links, are highly inefficient in terms of installation time and cost. To improve efficiency, shared media production networks that connect all involved actors over a large geographical area, are currently being deployed. The traffic in such networks is often predictable, as the timing and bandwidth requirements of data transfers are generally known hours or even days in advance. As such, the use of advance bandwidth reservation (AR) can greatly increase resource utilization and cost efficiency. In this paper, we propose an Integer Linear Programming formulation of the bandwidth scheduling problem, which takes into account the specific characteristics of media production networks, is presented. Two novel optimization algorithms based on this model are thoroughly evaluated and compared by means of in-depth simulation results.

In this paper, delay/buffer control for mixed traffic (DBCM) using feedback control is proposed to provide quality of service (QoS) such as delay and packet loss for mixed traffic in high-speed communication networks. Mathematical models are suggested to describe networks including real-time traffic (RTT) and non-real-time traffic (NRT) sources. DBCM directly controls delay to meet strict delay requirement of RTT and controls the NRT buffer to prevent buffer overflow. DBCM is evaluated in terms of punctuality rate and packet loss ratio in the network with an example of mixed traffic. The simulation result shows that DBCM performs better than a scheme combining a bandwidth reservation for RTT and a rate-based heuristic approach for NRT.

This paper compares five different schemes ‐ called CHOI, NAG, AG, BHARG, and NCBF ‐ for reserving bandwidths for handoffs and admission control for new connection requests in QoS-sensitive cellular networks. CHOI and NAG are to keep the handoff dropping probability below a target value, AG is to guarantee no handoff drops through per-connection bandwidth reservation, and BHARG and NCBF use another type of per-connection bandwidth reservation. CHOI predicts the bandwidth required to handle handoffs by estimating possible handoffs from adjacent cells, then performs admission control for each newly-requested connection. On the other hand, NAG predicts the total required bandwidth in the current cell by estimating both incoming and outgoing handoffs at each cell. AG requires the set of cells to be traversed by the mobile with a newly-requested connection, and reserves bandwidth for each connection in each of these cells. The last two schemes reserve bandwidth for each connection in the predicted next cell of a mobile where the two schemes use different admission control policies. We adopt the history-based mobility estimation for the first two schemes. Using extensive simulations, the five schemes are compared quantitatively in terms of (1) handoff dropping probability, connection-blocking probability, and bandwidth utilization; (2) dependence on the design parameters; (3) dependence on the accuracy of mobility estimation; and (4) complexity. The simulation results indicate that CHOI is the most desirable in that it achieves good performance while requiring much less memory and computation than the other four schemes.

The wireless ad hoc networks are highly vulnerable to distributed denial of service(DDoS) attacks because of its unique characteristics such as open network architecture, shared wireless medium and stringent resource constraints. These attacks throttle the tcp throughput heavily and reduce the quality of service(QoS) to end systems gradually rather than refusing the clients from the services completely. In this paper, we discussed the DDoS attacks and proposed a defense scheme to improve the performance of the ad hoc networks. Our proposed defense mechanism uses the medium access control (MAC) layer information to detect the attackers. The status values from MAC layer that can be used for detection are Frequency of receiving RTS/CTS packets, Frequency of sensing a busy channel and the number of RTS/DATA retransmissions. Once the attackers are identified, all the packets from those nodes will be blocked. The network resources are made available to the legitimate users. We perform the simulation with Network Simulator NS2 and we proved that our proposed system improves the network performance. &nbsp

In the centralized polling mode in IEEE 802.16e, a base station (BS) polls mobile stations (MSs) for bandwidth reservation in one of three polling modes; unicast, multicast, or broadcast pollings. In unicast polling, the BS polls each individual MS to allow to transmit a bandwidth request packet. This paper presents an analytical model for the unicast polling of bandwidth request in IEEE 802.16e networks over Gilbert-Elliot error channel. We derive the probability distribution for the delay of bandwidth requests due to wireless transmission errors and find the loss probability of request packets due to finite retransmission attempts. By using the delay distribution and the loss probability, we optimize the number of polling slots within a frame and the maximum retransmission number while satisfying QoS on the total loss probability which combines two losses: packet loss due to the excess of maximum retransmission and delay outage loss due to the maximum tolerable delay bound. In addition, we obtain the utilization of polling slots, which is defined as the ratio of the number of polling slots used for the MS's successful transmission to the total number of polling slots used by the MS over a long run time. Analysis results are shown to well match with simulation results. Numerical results give examples of the optimal number of polling slots within a frame and the optimal maximum retransmission number depending on delay bounds, the number of MSs and the channel conditions. Copyright © 2009 The Institute of Electronics, Information and Communication Engineers.

In this paper we present time slot groups (TSG), a novel, efficient data structure for QoS-constrained advance bandwidth reservation and admission control. The data structure divides the time horizon into T equally sized time slots and can be used for serving efficiently complex bandwidth reservation requests specifying the duration of the reservation, the minimum required bandwidth, the earliest possible starting time and the latest possible finish time. The data structure supports reservation queries in time O(k+(T/k)* log(k)) and reservation updates in time O(k+(T/k)), where k is a user-defined parameter.

Adaptive admission control reserves bandwidth for handoff calls by distributing bandwidth reservation values for each call to the neighboring base stations. The series of bandwidth reservation values distributed after k-th handoff determines the bandwidth reservation policy. This paper analyzes relationship between bandwidth reservation policies and call level QoS when user mobility is changing. We define classes of non-aggressive and aggressive bandwidth reservation policies. We show that bounded call level QoS under heterogeneous user mobilities can be achieved only by using aggressive bandwidth reservation policies. Examples of non-aggressive and aggressive bandwidth reservation policies are shown.

Three reservation algorithms for the limited-availability system are proposed and compared in the paper. These algorithms can be used for call blocking equalisation in outgoing links of multiservice switching networks. Two approximate methods of equalised blocking probability calculation in the system with limited availability are proposed. Results of analytical calculations are compared with results of digital simulation of limited availability groups and switching networks with reservation. These researches have confirmed a great accuracy of the proposed calculation methods. The formulae derived by the authors can be useful for the analysis and design of ISDN and B-ISDN systems.

ATM based Virtual Private Networks(AVPNs) are embedded in public ATM network to provide an efficient transport service to a multisite customer using virtual levels of ATM. In this paper we propose a centralized protocol for resource allocation in AVPNs and compare its performance with that of the previously proposed strategies. We analyze the protocol to get average burst delay and burst loss probability in case of finite buffering at the customer sites.