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文章分析一种改进的基于分布式的以太网无源光网络的接入结构.根据该结构的特点.在IPACT取制DBA算法的基础上进行改进.设计了两种DBA算法,一种是支持ONU传输的顺序DBA算法.另一种是支持全局考虑机制的DBA算法. 相似文献
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Rizwan Aslam Butt Sevia Mahdaliza Idrus Nadiatulhuda Zulkifli M. Waqar Ashraf 《International Journal of Communication Systems》2018,31(3)
For an efficient utilization of the upstream bandwidth in passive optical network, a dynamic bandwidth assignment mechanism is necessary as it helps the service providers in provisioning of bandwidth to users according to the service level agreements. The scheduling mechanism of existing schemes, immediate allocation with colorless grant and efficient bandwidth utilization (EBU), does not assign the surplus bandwidth to a specific traffic class and only divides it equally among the optical network units (ONUs). This results in overreporting of ONU bandwidth demand to the optical line terminal and causes wastage of bandwidth and increase in delays at high traffic loads. Moreover, the EBU also assigns the unused bandwidth of lightly loaded ONU queues to the overloaded queues through an Update operation. This Update operation has a flaw that it borrows the extra bandwidth to a queue in the current service interval, if the queue report is higher than its service level agreement and refunds in next service interval. This borrow‐refund operation causes reduced bandwidth allocation to the lower priority classes and increases their delay and frame loss. This study improves both these weaknesses. The simulation results show that the proposed scheme uses bandwidth efficiently and reduces mean upstream delay of type‐2 (T2) traffic class by 38% and type‐3 (T3) up to 150% compared to immediate allocation with colorless grant at a cost of up to 10% higher delay for T2. However, T4 performance improves by 400% compared to EBU with slight increase in delay for T2 traffic class. Overall, it shows a balanced performance for all the traffic classes and minimizes the bandwidth waste per cycle as well as the frame loss rate. 相似文献
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通过阐述以太网无源光网络(EPON)系统信道传输数据方式以及动态带宽分配的工作原理,进一步研究了动态带宽分配算法(DBA)在EPON系统中的应用。提出一种基于服务质量(QoS)的EPON系统动态带宽分配机制,该机制根据不同业务的优先级和动态带宽分配算法,灵活地分配上行带宽,提高了带宽利用率,改善了服务质量。 相似文献
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EPON中保证QoS的动态带宽分配算法 总被引:3,自引:3,他引:0
作为一种新技术,EPON系统采取在下行信道使用广播方式而在上行信道使用时分多址(TDMA)方式,为用户提供共享传输介质的接入方式,因此就需要一种接入控制机制来为用户分配带宽。为了使EPON系统更好地支持QoS并且进一步提高带宽利用率,提出了一种新的固定周期轮询动态带宽分配算法,针对不同时延特性业务采用不同的授权分配算法。算法包括两部分:OLT时ONU的调度以及ONU内部不同优先级的队列之间的调度。最后讨论了包时延、系统吞吐量等仿真结果和性能分析。 相似文献
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动态带宽分配是无源光网络上行时隙分配的关键技术,算法的设计和实现将极大的影响系统的性能.提出了一种新颖的DBA算法,称为智能加权公平算法,它是在基于加权公平算法的基础上改良而来,它在提高带宽分配准确率和效率的同时,简化了算法的实现难度. 相似文献
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以太网无源光网络(EPON)和IEEE 802.16(WiMAX)的融合网络在固定移动混合接入网中被认为是很有前景的接入方式.文中提出了3种WiMAX无线网络与EPON网络系统融合架构,融合系统同时具有光网络的高带宽和无线网络的灵活性.为了在接入网中支持QoS,本文为融合结构提出了一种动态带宽分配算法(DBA)和调度机... 相似文献
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er-ONU and intra-ONU fairness. Most importantly, it can flexibly adapt to the system composition variations and save efforts needed to modify the bandwidth scheduling mechanism during the migration process from GEPON to 10G EPON. 相似文献