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1.
《Lightwave Technology, Journal of》2008,26(14):2055-2063
2.
As broadband access is evolving from digital subscriber lines to optical access networks, Ethernet passive optical networks (EPONs) are considered a promising solution for next generation broadband access. The point‐to‐multipoint topology of EPONs requires a time‐division multiple access MAC protocol for upstream transmission. In this paper, we propose a new enhanced dynamic bandwidth allocation algorithm with fairness called EFDBA for multiple services over EPONs. The proposed algorithm is composed of a fairness counter controller and a fairness system buffer in the optical line terminal. The EFDBA algorithm with fairness can provide increased capability and efficient resource allocation in an EPON system. In the proposed EFDBA algorithm, the optical line termination allocates bandwidth to the optical network units in proportion to the fairness weighting counter number associated with their class and queue length. The proposed algorithm provides efficient resource utilization by reducing the unused remaining bandwidth made by idle state optical network units. 相似文献
3.
Medium access control is one of the crucial issues in the design of Ethernet passive optical networks. To ensure efficient transmission, an EPON system must employ a MAC mechanism to arbitrate access to the shared medium in order to avoid data collisions in the upstream direction and at the same time efficiently share the upstream transmission bandwidth among all ONUs. The purpose of this article is to provide a good understanding of the MAC issue, discuss the major problems involved (e.g., multiple access, bandwidth allocation, transmission scheduling, and quality of service support), and present an overview of the state-of-the-art solutions proposed thus far to the problems. It is also our purpose to motivate further studies on the problems described in this article 相似文献
4.
Jing Xie Shengming Jiang Yuming Jiang 《Communications Magazine, IEEE》2004,42(8):S32-S39
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. 相似文献
5.
Bandwidth allocation for multiservice access on EPONs 总被引:4,自引:0,他引:4
Ethernet passive optical networks are a low-cost high-speed solution to the bottleneck problem of the broadband access network. A major characteristic of EPONs is the shared upstream channel among end users, mandating efficient medium access control to facilitate statistical multiplexing and provision multiple services for different types of traffic. This article addresses and provides an overview of the upstream bandwidth allocation issue for multiservice access provisioning over EPONs, and proposes an algorithm for dynamic bandwidth allocation with service differentiation. Based on the multipoint control protocol (MPCP) and bursty traffic prediction, our algorithm enhances QoS metrics such as average frame delay, average queue length, and frame loss probability over other existing protocols 相似文献
6.
随着高清IPTV、在线游戏等业务的发展,用户对于带宽的需求日益增加,10G-EPON技术应运而生。与传统的EPON系统一样,10G-EPON系统的动态带宽分配问题仍然十分关键。带宽分配方式的选择对于如何避免传输冲突,提高系统的带宽利用率且保障服务质量都非常重要。在已有算法的基础之上,提出一种改进型动态带宽分配算法。该算法重点确保高优先级业务的服务要求,在一定程度上体现了不同等级ONU之间的公平性,提高了上行带宽利用率。 相似文献
7.
8.
提出一种新的基于国际标准和区分服务(Differentiated Service)的以太无源光网络(EPON)动态带宽分配(dynamic bandwidth allocation,DBA)方案,该方案不仅能够在上行方向为多个光网络单元(Optical Network Unit,ONU)高效并公平地分配有限的带宽,而且能够最大限度地保证不同ONU间及不同通信等级间的公平性以及高等级通信的服务质量(QoS)要求.仿真结果证明,与现有算法相比,本算法在延时和利用率方面均有改进,在重负荷情况下改进更明显. 相似文献
9.
This paper proposes a new dynamic bandwidth allocation system for Ethernet Passive Optical Networks (EPONs), subject to requirements of fairness, efficiency, and cost. An Optical Line Terminal (OLT)-centric bandwidth allocation model is proposed which employs a credit pooling technique combined with a weighted-share policy to partition the upstream bandwidth among different classes of service, and to prevent Optical Network Units (ONUs) from monopolizing the bandwidth. The OLT-centric model allows global optimization of network resources, a characteristic which is not found in many earlier proposals. Supported by the new bandwidth allocation, the paper proposes a joint-ONU interval-based packet scheduling algorithm, referred to herein as COPS (Class-of-service Oriented Packet Scheduling), that meets the requirements set out above. We compare COPS with another well-known scheduling algorithm which employed a standard priority-based bandwidth sharing. We show that COPS is superior in terms of network utilization and maximum packet delay, with the consequence of an increase in average packet delay for the premium traffic. This drawback is overcome by combining COPS with a rate-based optimization scheme. 相似文献
10.
I dynamic bandwidth allocation (DBA) scheme, an inter–optical network unit (ONU) bandwidth scheduling, is presented to provide quality of service (QoS) to different classes of packets in Ethernet passive optical networks (EPONs). This scheme, referred to as TADBA, is based on efficient threshold reporting from, and adaptive polling order rearranging of, ONUs. It has been shown that the network resources are efficiently allocated among the three traffic classes by guaranteeing the requested QoS, adaptively rearranging the polling orders, and avoiding nearly all fragmentation losses. Simulation results using an OPNET network simulator show that TADBA performs well in comparison to the available allocation scheme for the given parameters, such as packet delay and channel utilization. 相似文献
11.
EPON(Ethernet Passive Optical Networks)系统中有两个问题:一是EPON中最关键成分之一--动态带宽分配;二是EPON的上行(ONU到OLT)为多点到点的传输,不能与以太网标准设备兼容.结合这两个问题介绍一种优化的带宽分配方案,它由基于参数的访问权限控制(CAC)机制、平均分配算法(EDA)和带宽预留轮询算法(BGP)组成,并将算法信息加入EPON内部帧,根据网络用户的服务等级(SLA)分配带宽,为EPON与以太网标准设备兼容提供算法支持,优化EPON网络的性能. 相似文献
12.
Noemí Merayo Tamara Jiménez Ramón J. Durán Patricia Fernández Ignacio de Miguel Rubén M. Lorenzo Evaristo J. Abril 《Photonic Network Communications》2010,19(3):257-264
A novel interleaved polling algorithm for Long-Reach EPONs is proposed in order to simultaneously provide subscriber and class
of service differentiation. It is demonstrated that the new polling algorithm applied to a typical 100 km Long-Reach EPON
performs better than centralized methods, where bandwidth prediction is needed to overcome the higher round trip time in which
ONUs cannot transmit. As polling methods in Long-Reach EPONs do not require prediction, they are much simpler and show less
computational complexity than centralized schemes, avoiding the inaccuracy of bandwidth prediction. Simulation results show
that the new algorithm increases the achieved throughput when compared to centralized algorithms with traffic prediction,
obtaining a significant reduction of both mean packet delay and packet loss ratio for the highest priority service level profiles. 相似文献
13.
14.
Kyeong-Eun Han Won-Hyuk Yang Debasish Datta Young-Chon Kim 《Photonic Network Communications》2008,15(3):191-202
In this article, we examine a candidate architecture for wavelength-division multiplexed passive optical networks (WDM-PONs)
employing multiple stages of arrayed-waveguide gratings (AWGs). The network architecture provides efficient bandwidth utilization
by using WDM for downstream transmission and by combining WDM with time-division multiple access (TDMA) for upstream transmission.
In such WDM-PONs, collisions may occur among upstream data packets transmitted simultaneously from different optical networking
units (ONUs) sharing the same wavelength. The proposed MAC protocol avoids such collisions using a request/permit-based multipoint
control protocol, and employs a dynamic TDMA-based bandwidth allocation scheme for upstream traffic, called minimum-guaranteed
maximum request first (MG-MRF), ensuring a reasonable fairness among the ONUs. The entire MAC protocol is simulated using
OPNET and its performance is evaluated in terms of queuing delay and bandwidth utilization under uniform as well as non-uniform
traffic distributions. The simulation results demonstrate that the proposed bandwidth allocation scheme (MG-MRF) is able to
provide high bandwidth utilization with a moderately low delay in presence of non-uniform traffic demands from ONUs. 相似文献
15.
Cyclic Polling-Based Dynamic Bandwidth Allocation for Differentiated Classes of Service in Ethernet Passive Optical Networks 总被引:3,自引:0,他引:3
Ethernet passive optical networks (EPONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and customer sites. Dynamic bandwidth allocation (DBA) provides statistical multiplexing between the optical network units for efficient upstream channel utilization. To support dynamic bandwidth distribution, a cyclic polling-based DBA algorithm for differentiated classes of service in EPONs is proposed. It is shown that an interleaved polling scheme severely decreases downstream channel capacity for user traffic when the upstream network load is low. To obtain realistic simulation results, synthetic traffic that exhibits the properties of self-similarity and long-range dependence is used. Network performance under various loads is analyzed. Specifically, frame delays for different classes of traffic are considered. 相似文献
16.
In the EPON, any failure of optical line terminal (OLT) or feeder fiber can halt the entire system. Many previous studies
proposed dedicated protection architectures to protect the critical components, which results in high cost for deployment.
To achieve high reliability and low-cost for deployment, this article proposes a novel fault-tolerant Multi-EPON system with
cost-effective shared protection through Bridge ONUs. Under failures, the Bridge ONU controls the faulty EPON, plays the role
of OLT and the transmission of faulty EPONs are restored by relaying to other interconnected adjacent EPONs. The minimum hop-count
relay algorithm and the relay window mechanism are also proposed for the Multi-EPON system to efficiently help data relaying
to the central office (CO). Furthermore, the one-wait dynamic bandwidth allocation enables the controller of affected Passive
Optical Networks (PONs) to obtain more up-to-date buffer information from each ONU in order to enhance overall system performance.
The simulation results show that the proposed Multi-EPON system can provide high system performance for different failure
situations in terms of throughput, average delay, maximum delay, and expedited forwarding (EF) jitter, especially in high
traffic loads.
相似文献
Liang-Yu KeEmail: |
17.
This article proposes a PRNN/ERLS-based predictive QoS-promoted dynamic bandwidth allocation (PQ-DBA) scheme for upstream
transmission in Ethernet passive optical network (EPON) systems. The proposed PQ-DBA scheme originally divides incoming packets
of voice, video, data service traffic into six priorities, where packets having less room before QoS requirements violation
or being in starvation situation will be dynamically promoted to high priority cycle-by-cycle. It predicts packets arriving
at prediction interval for ONUs using pipeline recurrent neural network (PRNN)/extended recursive least squares (ERLS) so
that the bandwidth allocation can be more up-to-date and then accurate. Simulation results show that the proposed PQ-DBA scheme
achieves higher system utilization and lower average voice, video, data packet delay time than the DBAM scheme [Luo and Ansari,
OSA J Opt Netw 4(9):561–572] by 4, and 21, 90, 43%, respectively, and the PQ-DBA scheme but without prediction by 2, and 26,
29, 34%, respectively. 相似文献
18.
Passive optical networks are a prominent broadband access solution to tackle the "last mile" bottleneck in telecommunications infrastructure. Data transmission over standardized PONs is divided into time slots. Toward the end of PON performance improvement, a critical issue relies on resource management in the upstream transmission from multiple optical network units (ONUs) to the optical line terminal (OLT). This includes resource negotiation between the OLT and the associated ONUs, transmission scheduling, and bandwidth allocation. This article provides an overview of the resource management issues along with the state-of-the-art schemes over time-division multiplexed PONs (TDM-PONs). We categorize the schemes in the literature based on their features, and compare their pros and cons. Moreover, we introduce a unified state space model under which all TDM-PON resource management schemes can be evaluated and analyzed for their system level characteristics. Research directions are also highlighted for future studies. 相似文献
19.
Ethernet passive optical networks (EPONs) have been considered as the one of the most promising candidates for next-generation
access networks. However, the EPON architecture although cost effective is bandwidth limited and quality of service (QoS)
support is still a major concern. In this paper, we propose a cost-efficient wavelength division multiplexing (WDM) EPON architecture.
We present two wavelength and bandwidth allocation algorithms with full QoS support to fulfill all requirements of new application
and services in a converged triple play network. We analyze and compare the presented models and algorithms in terms of delay,
jitter, queue occupancy, throughput and overall system performance. We conduct detailed simulation experiments to study the
performance and validate the effectiveness of the proposed architecture and algorithms. 相似文献
20.
In this paper, we propose a novel passive optical network (PON) architecture that has multiple optical line terminals (OLTs). Unlike existing PONs where all ONUs are connected to a single OLT, the proposed multi-OLT PON allows subscribers to choose their own service providers from among multiple OLTs. Service companies and subscribers can make service level agreements (SLA) on the amount of bandwidth that each OLT or ONU requires. A new control protocol and bandwidth allocation algorithms appropriate in this new PON environments are suggested. For the downstream, a scheme to share the bandwidth among multiple OLTs is studied to maximize the total transmitted packets while guaranteeing each OLT’s SLA. A modified Limited Dynamic Bandwidth Allocation named mLimited scheme is also proposed for upstream transmission toward multiple OLTs, which maximizes the total upstream throughput while minimizing the delay of each ONU. Performances of the proposed PON architecture and algorithms are analyzed. A PON system with two OLTs and 16 ONUs is used in the analysis. Self-similar traffic reflecting current packet distribution is used in the packet generation. The results show that the proposed DBA schemes efficiently manage bandwidth even when the occurred traffic load is quite different from the reserved bandwidth. It is found that the proposed PON architecture is appropriate in supporting diverse services in future high-speed optical access network. 相似文献