Virtual path long-term bandwidth allocation algorithm for ATMnetworks using simulated annealing

The long-term virtual path (VP) bandwidth allocation process requires the use of heuristics or artificial intelligence to find the number of virtual circuits that can multiplex by each VP to maximise the quality of service, which is defined here in terms of the call blocking probabilities. The authors propose a new technique, based on simulated annealing, for performing the allocation process. It substantially improves upon previous proposals     

Design of a fair bandwidth allocation policy for VBR traffic in ATMnetworks

Since real-time variable bit rate (VBR) traffic is inherently bursty, dynamic bandwidth allocation is necessary for ATM streams that carry VBR traffic. In order to provide quality-of-services (QoS) guarantees and to reduce the computational complexity, an hybrid of guaranteed and dynamic adaptive allocation scheme requires to be implemented. Typical dynamic allocations to competing streams are done in the form of linear proportions to the bandwidth requirements. We show that during temporary link congestion such proportional arrangements can give rise to unequal queue growth and, subsequently, degraded QoS. This is found to be true even for streams that belong to the same VBR class and share identical long term traffic characteristics and QoS requirements. In this paper, four allocation algorithms are presented and analyzed in terms of their fairness and QoS potential for real-time VBR traffic. We propose and show that a novel allocation strategy, termed Minmax, solves the mentioned problem of unfairness within a class. By maintaining a fair distribution of buffer length across the streams of a class, the proposed policy can achieve better and fairer QoS performance compared to the traditional methods. We present analytical results, proofs and a simulation study of the described algorithms. Four allocation policies for handling MPEG VBR video streams are simulated in the context of a wireless ATM (WATM) medium access control. The results show that in certain scenarios, the Minmax strategy can reduce losses by an order of magnitude, while decreasing delays substantially     

Applications of neurocomputing in traffic management of ATMnetworks

In the near future, high speed integrated networks, employing asynchronous transfer mode (ATM) cell switching and multiplexing technique, will be used to provide new and diverse mixture of services and applications. Multimedia teleconferencing, video-on-demand, television broadcasting, and distant learning are some examples of these emerging services. The ATM technique is based on the principle of statistical multiplexing, which is flexible enough to support different types of traffic while providing efficient utilization of the network's resources. New classes of techniques such as neural networks and fuzzy logic have many adaptive, learning and computational capabilities that can be utilized to design effective traffic management algorithms. The subject of this paper is to demonstrate how such neurocomputing techniques can be used to address ATM traffic management issues such as traffic characterization, call admission control, usage parameters control and feedback congestion control     

Diffusion approximation modeling for Markov modulated burstytraffic and its applications to bandwidth allocation in ATMnetworks

We consider a statistical multiplexer model, in which each of the K sources is a Markov modulated rate process (MMRP). This formulation allows a more general source model than the well studied “on-off” source model in characterizing variable bit rate (VBR) sources such as compressed video. In our model we allow an arbitrary distribution for the duration of each of the M states (or levels) that the source can take on. We formulate Markov modulated sources as a closed queueing network with M infinite-server nodes. By extending our earlier results we introduce an M-dimensional diffusion process to approximate the aggregate traffic of such Markov modulated sources. Under a set of reasonable assumptions we then show that this diffusion process can be expressed as an M-dimensional Ornstein-Uhlenbeck (O-U) process. The queueing behavior of the buffer content is analyzed by applying a diffusion process approximation to the aggregate arrival process. We show some numerical examples which illustrate typical sample paths, and autocorrelation functions of the aggregate traffic and its diffusion process representation. Simulation results validate our proposed approximation model, showing good fits for distributions and autocorrelation functions of the aggregate rate process and the asymptotic queueing behavior. We also discuss how the analytical formulas derived from the diffusion approximation can be applied to compute the equivalent bandwidth for real-time call admission control, and how the model can be modified to characterize traffic sources with long-range dependence     

Bandwidth allocation and connection admission control in ATMnetworks

Asynchronous transfer mode (ATM) is the transmission format for almost all future communication networks, including broadband integrated services digital networks (B-ISDN). The key feature of ATM is its high flexibility in bandwidth allocation. Instead of reserving capacity for each connection, the bandwidth is allocated on demand. As a consequence, packets (called cells in ATM terminology) might be lost. To guarantee a given quality of service (QoS), some kind of control is needed to decide whether to accept or to reject an incoming connection. A connection is accepted only if the network has sufficient resources to achieve the QoS required by the user without affecting the QoS of the existing connections. In ATM networks, connection admission control (CAC) is responsible for this decision. It is a very complex function because the traffic may vary greatly and have poorly known characteristics. This paper describes CAC procedures proposed in the literature and discusses issues related to bandwidth allocation in ATM networks. It shows that CAC and statistical multiplexing are only needed for certain connections     

一种APON上行带宽分配方案

文中介绍了APOW（ATM无源光网络）,在此基础上提出了APON上行带宽动态分配的一种方案--“最小分配”方案：即光线路终端（OLT）在分配上行带宽时,首先满足各光网络单元（ONU）的基本带宽需求,以保证电话等实时业务的传输;同时又以特定的算法使ONU中的上行发送缓冲队列最短。最后,使用仿真手段对本方案与“平均分配”方案进行了性能比较。“最小分配”方案的平均信元接入时延、ONU上发缓冲区尺寸、上行带宽使用效率和信元丢失率等性能指标均优于“平均分配”方案。     

Optimal bit allocation for coding of video signals over ATMnetworks

We consider optimal encoding of video sequences for ATM networks. Two cases are investigated. In one, the video units are coded independently (e.g., motion JPEG), while in the other, the coding quality of a later picture may depend on that of an earlier picture (e.g., H.26x and MPEGx). The aggregate distortion-rate relationship for the latter case exhibits a tree structure, and its solution commands a higher degree of complexity than the former. For independent coding, we develop an algorithm which employs multiple Lagrange multipliers to find the constrained bit allocation. This algorithm is optimal up to a convex-hull approximation of the distortion-rate relations in the case of CBR (constant bit-rate) transmission. It is suboptimal in the case of VBR (variable bit-rate) transmission by the use of a suboptimal transmission rate control mechanism for simplicity. For dependent coding, the Lagrange-multiplier approach becomes rather unwieldy, and a constrained tree search method is used. The solution is optimal for both CBR and VBR transmission if the full constrained tree is searched. Simulation results are presented which confirm the superiority in coding quality of the encoding algorithms. We also compare the coded video quality and other characteristics of VBR and CBR transmission     

A dynamic bandwidth allocation scheme for differentiated services in EPONs

Passive optical networks bring high-speed broadband access via fiber to the business, curb and home. Among various types of PONs, Ethernet PONs are gaining more and more attention since they are built on widely used Ethernet technology and can offer high bandwidth, low cost and broad services. EPONs use a point-to-multipoint topology, in which multiple optical network units share one uplink channel to transmit multimedia traffic to a control element, the optical line terminal. To avoid data collision on the shared uplink channel, a key issue in EPONs is a contention-free MAC protocol for the OLT to schedule the transmission order of different ONUs. In this article we first review some DBA schemes available in the literature, then propose a two-layer bandwidth allocation scheme that implements weight based priority for this need. To maximally satisfy the requests of all ONUs and provide differentiated services, an ONU is allowed to request bandwidth for all its available traffic, and all traffic classes proportionally share the bandwidth based on their instantaneous demands. The weight set for each class not only prevents high-priority traffic from monopolizing the bandwidth under heavy load but also ensures a minimum bandwidth allocated to each traffic class.     

A tabu search heuristic for bandwidth allocation in fixed WiMAX

In this paper, we propose a mathematical model with the aim to give guidelines for the dimensioning of fixed WiMAX bandwidth provisioning service to residential customers. Our proposal relies on the modeling of a CAC policy associated to a priority-based bandwidth sharing strategy. Both mechanisms aim to satisfy Quality of Service constraints while maximizing the gain of the system. But unlike in Khemiri et al. (Optimal call admission control for an IEEE 802.16 wireless metropolitan area network. In: International Conference on Network Control and Optimization, 2007, accepted), we do not necessarily seek here for an optimal CAC policy. We rather consider a coordinate convex CAC policy, whose mathematical modeling leads to a tractable analytical resolution. We chose the Guaranteed Minima (GM) policy, which consists in reserving a specified amount of bandwidth for each traffic class. The remaining bandwidth is shared between all traffic classes. The purpose of the paper is to determine, using an analytical model and a heuristic approach, the nearly-optimal sizes of the GM reservation thresholds associated to each type of connection. The main concern here is to propose simple and robust computational methods, which can be easily and efficiently used to dimension a realistic WiMAX network.     

一种带阈值的EPON动态带宽分配算法

文章提出一种适用于千兆以太网无源光网络(EPON)的支持多业务的动态带宽分配(DBA)算法,该算法采用单阈值整帧上报和阈值动态调整解决了EPON中存在的时隙碎片和队头阻塞问题.同时,文章对算法中的关键参数--设定周期的大小与算法性能的关系进行了深入的研究分析,以指导算法设定周期的确定.     

A bandwidth allocation strategy for a FDM multichannel modem

Implementing a frequency division multiplexing (FDM)-based modem for a multichannel application requires a bandwidth allocation strategy. That is, one must decide how to allocate total bandwidth to individual channels such that (a) the desired aggregate rate can be achieved and (b) the desired individual channel bit rates can be achieved. An optimal strategy for bandwidth allocation is proposed. The multitone channel result is used to specify a scheme to allocate four separate channels. The allocation strategy assigns to each subchannel a constellation that is equal in size to that of an equivalent single-band modem operating at the aggregate rate. In this manner, bandwidth is allocated proportional to the desired bit rate on a particular subchannel. Power allocation will be done to maintain a constant probability of error between all channels. This technique will allow the user to split total bandwidth to meet error performance objectives, provided that the desired aggregate rate does not exceed the maximum bit rate allowed by channel conditions     

EPON中一种动态带宽分配算法

以太无源光网络(EPON)被认为是下一代宽带接入的最有效的解决方案。文章提出了一种新的基于EOPN提供多种服务的动态带宽分配算法。为了能够应用这种算法还给出了协助带宽分配多点控制协议(MPCP)的控制消息的格式。     

一种公平的EPON动态带宽分配算法

提出一种EPON上行链路动态带宽分配算法一周期比例DBA。ONU基于多门限周期地上报带宽请求，OLT根据ONU的带宽请求及其合约带宽进行动态带宽分配。当多个ONU竞争系统带宽时，OLT按照ONU合约带宽的比例进行带宽分配。仿真结果表明：周期比例DBA算法在实现高带宽利用率的同时又具有良好的公平性。     

Dynamic bandwidth allocation for interactive applications

The transmission of stored video across an ATM network is considered for interactive applications with bounded reaction times. The performance of the services renegotiated VBR (RVBR) and renegotiated CBR (RCBR) is investigated for this class of applications by trace-driven simulations. The goal is to determine the most efficient service for interactive applications. Here we present three basic results. First, for delay sensitive applications smoothing the video stream in advance is much more efficient than adding smoothing buffers to the network switches. Second, services with renegotiation (RCBR, RVBR) are better suited for interactive applications than the static services CBR and VBR. Third, the RVBR service with a deterministic call admission control scheme is the best choice for interactive applications that require small reaction times.     

GPON中的动态带宽分配

首先介绍了吉比特无源光网络(GPON)的复用结构和所承载的业务,随后就GPON的关键技术之一——动态带宽分配作了详细论述,分别从带宽分配的功能、对象和过程这几个方面作了介绍,最后比较了GPON和宽带无源光网络(BPON)在动态带宽分配方面的不同。     

A game-based algorithm for fair bandwidth allocation in Fibre-Wireless access networks

Fibre-Wireless (FiWi) access networks have been proposed as flexible and cost-effective solutions for future access networks. At the wireless mesh section, wireless routers have to forward both local traffic from directly connected users and foreign traffic from neighbour wireless routers. How to allocate resources to local and foreign traffic at each router in a balanced way, while avoiding starvation of routers requiring less resources, is a fundamental issue that must be solved so that new services emerge. Here, we develop a repeated game framework for bandwidth allocation and propose an algorithm that allocates bandwidth in a fair manner. The algorithm is able to detect over claiming routers and avoid possible denial of service that these may cause to others. Moreover, unfruitful use of resource is prevented, avoiding the forwarding of packets that would be dropped at some point later in the path, and queueing delay conditions are kept similar among local and foreign traffic. These fair network conditions open way for QoS support since it is easier to ensure the operationality of services.     

一种新的支持ONU睡眠模式的EPON带宽分配算法

在支持ONU睡眠模式的带宽分配机制基础上,结合可变周期的间插轮询算法和周期性轮询动态带宽分配算法的优点,提出了一种新的带宽分配算法。上行方向,新算法既保证数据包延时和平均队列长度较小,又避免了前两算法所存在的缺陷;下行方向,新算法的平均包延时小于轮询周期Tcycle,平均队列长度小于周期Tcycle与下行最大链路速率之积。     

A novel bandwidth allocation scheme for OTSS-enabled flex-grid intra-datacenter networks

Photonic Network Communications - Optical circuit switching networks have been recognized as a promising solution for inter-datacenter networks. However, for intra-datacenter networks, they may...     

A low-state packet marking framework for approximate fair bandwidth allocation

Misbehaving, non-congestion-reactive traffic is on the rise in the Internet. One way to control misbehaving traffic is to enforce local fairness among flows. Locally fair policies, such as fair-queueing and other fair AQM schemes, are inadequate to simultaneously control misbehaving traffic and provide high network utilization. We thus need to enforce globally fair bandwidth allocations. However, such schemes have typically been stateful and complex to implement and deploy. In this letter, we present a low state, lightweight scheme based on stateless fair packet marking at network edges followed by RIO queueing at core nodes, to control misbehaving flows with more efficient utilization of network bandwidth. Additionally, with low-state feedback from bottleneck routers, we show that, in practice, we can approximate global max-min fairness within an island of routers. We show, using simulations, that we can indeed control misbehaving flows and provide more globally fair bandwidth allocation.     

一种用于EPON的新型DBA算法

分析了经典轮询算法的优缺点,提出一种保证QoS的新型DBA算法--DGPRA(Divided-period Grant Partly Reaving Arithmetic,分周期授权部分抢占算法).该算法基于轮询的思想,从实用的角度为业务进行了分类,对三种不同的业务提出了新型处理策略:对语音业务预留带宽,对视频和数据业务细分循环周期,分级循环.同时,这种算法中还引入了新的抢占机制.仿真结果表明:该算法有良好的时延特性,特别有利于保证高级业务的QoS.