共查询到20条相似文献,搜索用时 0 毫秒
1.
The design of OBS networks that guarantee QoS provisioning for different classes of traffic is a major topic under current
research. In this work we formulate a unified framework for studying QoS in OBS networks with a GMPLS-based control plane.
We use this framework in order to investigate two problems. First, the configuration of the parameters of an aggregation strategy
so that a given Forwarding Equivalency Class observes its corresponding QoS requirements. Second, we address the problem of
planning a whole OBS network given a series of QoS constraints for each one of the Forwarding Equivalency Classes in the network.
The presented QoS framework constitutes a valuable tool for studying QoS-related issues in OBS networks. 相似文献
2.
3.
FRR for latency reduction and QoS provisioning in OBS networks 总被引:13,自引:0,他引:13
Jingxuan Liu Ansari N. Ott T.J. 《Selected Areas in Communications, IEEE Journal on》2003,21(7):1210-1219
We propose a forward resource reservation (FRR) scheme to reduce the data burst delay at edge nodes in optical burst switching (OBS) systems. We also explore algorithms to implement the various intrinsic features of the FRR scheme. Linear predictive filter (LPF)-based methods are investigated and demonstrated to be effective for dynamic burst-length prediction. An aggressive resource reservation algorithm is proposed to deliver a significant performance improvement with controllable bandwidth cost. By reserving resources in an aggressive manner, an FRR system can reduce both the signaling retransmission probability and the bandwidth wastage as compared with a system without the aggressive reservation. An FRR-based QoS strategy is also proposed to achieve burst delay differentiation for different classes of traffic. Theoretical analysis and simulation results verify the feasibility of the proposed algorithms and show that our FRR scheme yields a significant delay reduction for time-critical traffic without incurring a deleterious bandwidth overhead. 相似文献
4.
光突发交换(OBS)是构造下一代光互联网最有前途的解决方案之一.首先简单介绍了在OBS网络中实现QoS的几种传统机制,接着对波长分组预留策略提出了一种改进方案,并分析了其优越性和可行性. 相似文献
5.
6.
This article presents three versions of a novel MAC protocol for IEEE 802.11 ad-hoc networks called Busy Signal-based Mechanism turned On (BusySiMOn) (This is an extended version of our conference paper: [15]). The key idea of the proposed solution is based on an intelligent two-step reservation procedure combined with the advantages of EDCA service differentiation. The former alleviates the hidden node problem while the latter ensures compatibility with the IEEE 802.11 standard. Simulation results obtained for saturated and non-saturated network conditions emphasize the advantages of the new protocol over the currently used four-way handshake mechanism in terms of fairness, throughput, and average frame delay. 相似文献
7.
8.
《AEUE-International Journal of Electronics and Communications》2014,68(1):44-50
In optical burst switching (OBS) networks, burst contentions in OBS core nodes may cause data loss. To reduce data loss, retransmission scheme has been applied. However, uncontrolled retransmission may increase network load significantly and data loss probability defeating the retransmission purpose. In addition, in a priority traffic existing OBS network, OBS nodes may apply different retransmission mechanisms to priorities bursts for quality-of-service (QoS) support. This study has developed a controlled retransmission scheme for prioritized burst segmentation to support QoS in OBS networks. Unlike previous works in the literature, we have set a different value to retransmission probability at each contention and propose a retransmission analytical model for burst segmentation contention resolution scheme. In addition, we have applied the proposed retransmission scheme to the prioritized burst segmentation for QoS support. We have taken into account the load at each link due to both fresh and retransmitted traffic, and have calculated the path blocking probability and byte loss probability (ByLP) for high-priority and low-priority burst to evaluate network performance. An extensive simulation has been proposed to validate our analytical model. 相似文献
9.
Burst assembly is one of the key factors affecting the TCP performance in optical burst switching (OBS) networks. When the
TCP congestion window is small, the fixed-delay burst assembler waits unnecessarily long, which increases the end-to-end delay
and thus decreases the TCP goodput. On the other hand, when the TCP congestion window becomes larger, the fixed-delay burst
assembler may unnecessarily generate a large number of small-sized bursts, which increases the overhead and decreases the
correlation gain, resulting in a reduction in the TCP goodput. In this paper, we propose adaptive burst assembly algorithms
that use the congestion window sizes of TCP flows. Using simulations, we show that the usage of the congestion window size
in the burst assembly algorithm significantly improves the TCP goodput (by up to 38.4% on the average and by up to 173.89%
for individual flows) compared with the timer-based assembly, even when the timer-based assembler uses the optimum assembly
period. It is shown through simulations that even when estimated values of the congestion window size, that are obtained via
passive measurements, are used, TCP goodput improvements are still close to the results obtained by using exact values of
the congestion window. 相似文献
10.
11.
提出了一种基于虚拟突发光突发交换的(OBS)网络业务疏导机制TG-VB(traffic grooming based on virtual burst)。作为一种多粒度动态业务疏导机制,TG-VB将常规突发通过"逻辑汇聚"组成虚拟突发,增大核心网中业务传输粒度;同时,TG-VB根据虚拟突发整体传输、整体调度的特点,为汇聚的常规突发动态地选择最优的共用传输路径。仿真结果表明,与采用传统疏导机制的OBS网络相比,TG-VB能够有效地减轻核心节点的通信处理开销,降低对网络节点端口数量的需求;在相同负载条件下,TG-VB可极大地提高波长信道利用率。 相似文献
12.
提出了一种基于优先级的偏射路由机制,该机制通过分割偏射优先级低的突发包来保证高优先级突发包的QoS.仿真结果表明,高优先级突发包的丢失率比低优先级的要低,并且突发包的丢失率随数据信道数目的增加而降低.该机制不仅能够有效地降低突发包的丢失率,而且能够为高优先级突发包提供很好的QoS保障. 相似文献
13.
One of the key problems to hinder the realization of optical burst switching(OBS) technology in the core networks is the losses due to the contention among the bursts at the core nodes.Burst segmentation is an effective contention resolution technique used to reduce the number of packets lost due to the burst losses.In our work,a burst segmentation-deflection routing contention resolution mechanism in OBS networks is proposed.When the contention occurs,the bursts are segmented according to the lowest packet loss probability of networks firstly,and then the segmented burst is deflected on the optimum routing.An analytical model is proposed to evaluate the contention resolution mechanism.Simulation results show that high-priority bursts have significantly lower packet loss probability and transmission delay than the low-priority.And the performance of the burst lengths,in which the number of segments per burst distributes geometrically,is more effective than that of the deterministically distributed burst lengths. 相似文献
14.
提高带宽利用率和降低端到端的时间延迟是下一代网络性能的重要指标,文章简单扼要地介绍了目前OBS网络中在提高带宽利用率和降低端到端的时间延迟方面比较典型的两种组装算法:前向资源预留算法(Forward Resource Reservation,FRR)和精确组装FRR算法(Precision Assembly with Forward Resource Reservation,PAFRR).分析了这两种算法在带宽利用率提高以及平均时间延迟降低方面存在的问题.针对这些问题,提出了一种新的降低延迟的组装周期预测算法(As sembly Duration Forecasting,ADC)并进行了网络仿真.仿真结果验证了该算法在进一步提高带宽利用率方面和降低平均时间延迟方面的有效性. 相似文献
15.
研究了一种以突发组装的时间门限与包长门限的乘积为混合门限的按照步长大小进行自适应调整的突发组装算法,并且当第一个IP包进入组装队列时就对突发的大小及组装时间进行预测,最大程度上降低了端到端的延迟;仿真结果表明,在进行快速前向资源预留组装的基础上引入重传机制,可以在减少端到端延时的同时降低突发丢包率,较大地提高了OBS网络的性能. 相似文献
16.
17.
18.
19.
20.
We introduce an adaptive call admission control mechanism for wireless/mobile networks supporting multiple classes of traffic, and discuss a number of resource sharing schemes which can be used to allocate wireless bandwidth to different classes of traffic. The adaptive call admission control reacts to changing new call arrival rates, and the resource sharing mechanism reacts to rapidly changing traffic conditions in every radio cell due to mobility of mobile users. In addition, we have provided an analytical methodology which shows that the combination of the call admission control and the resource sharing schemes guarantees a predefined quality-of-service to each class of traffic. One major advantage of our approach is that it can be performed in a distributed fashion removing any bottlenecks that might arise due to frequent invocation of network call control functions. 相似文献