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Optical burst switching (OBS) is a promising technology for bridging the gap between optical wavelength switching and optical
packet switching. Optical signal transmission quality is subject to various types of physical impairment introduced by optical
fibers, switching elements, or other network components. The signal degradation due to physical impairment may be significant
enough such that the bit-error rate of received signals is unacceptably high at the destination, rendering the signal to not
usable. In this article, based on earlier study, we study the burst-scheduling problem in OBS networks using two control packets
for each data burst, taking into account physical impairment effects. We propose a burst-scheduling algorithm that accommodates
incoming bursts by primary path routing, deflection routing, and burst scheduling. We design an admission control mechanism
to use network resources efficiently. At an OBS node, the proposed algorithm schedules bursts for transmission by searching
for available resources as well as verifying signal quality. Our simulation results demonstrate that the proposed algorithm
is effective in terms of reducing the burst-blocking probability. 相似文献
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光突发交换(OBS)是兼顾光电路交换和光分组交换优点的一种折衷方案,是未来光互联网的一种实现形式。在我们即将组建的光突发交换试验网中,IP(因特网协议)数据在边缘节点被组装成突发包,需要使用数据卡和控制卡分别处理数据分组和控制分组。因此,对处理控制分组的控制卡电路的优化设计和实现进行了描述。 相似文献
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Blumenthal D.J. Prucnal P.R. Sauer J.R. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1994,82(11):1650-1667
Photonic packet switches offer high speed, data rate and format transparency, and flexibility required by future computer communications and cell-based telecommunications networks. In this paper, we review experimental progress in state-of-the-art photonic packet switches with an emphasis on all-optical guided-wave systems. The term all-optical implies that the data portion of a packet remains in optical format from the source to the destination. While the data remain all-optical, both optical and optoelectronic techniques have been used to process packet routing functions based on extremely simple routing protocols. An overview of the design issues for all-optical photonic packet switching is given and contrasted with electronic packet switch implementations. Low-level functions that have been experimentally implemented include routing, contention resolution, synchronization, and header regeneration. System level demonstrations, including centralized photonic switching and distributed all-optical multihop networks, will be reviewed 相似文献
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A fundamental issue in optical burst switching (OBS) networks is to solve the burst contention for the core node. In this
paper, a novel priority-based contention solution strategy for OBS networks is proposed. When the contention occurs, the burst
priority is considered firstly, and then the burst segmentation method is used for the low priority bursts in this strategy.
Ensuring the integrity of high priority bursts, part of the segmented bursts can be transmitted to the destination node via
combining wavelength conversion and optical buffer method. Simulation results show that the proposed scheme not only ensures
the integrity of high priority bursts, but also reduces the packet loss rate of the low priority bursts maximally, so that
it can support good quality of service (QoS) for the network. 相似文献
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光突发交换中的突发包组装技术研究 总被引:3,自引:0,他引:3
光突发交换是近几年出现的一种很有前途的光交换技术,比电路交换灵活,带宽利用率高,又比光分组交换易于实现,突发包的组装是光突发交换的关键技术,在很大程度上影响到光突发交换网络的性能。文中介绍了光突发包的格式,描述了交换网络中突发包组装所需的层次结构和功能结构,并给出了一种典型的生成算法。最后,对选择突发包组装时间应考虑的各种因素进行了系统的分析。 相似文献
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Presently, optical burst switching (OBS) technology is under study as a promising solution for the backbone of the optical Internet in the near future because OBS eliminates the optical buffer problem at the switching node with the help of no optical/electro/optical conversion and guarantees class of service without any buffering. To implement the OBS network, there are a lot of challenging issues to be solved. The edge router, burst offset time management, and burst assembly mechanism are critical issues. In addition, the core router needs data burst and control header packet scheduling, a protection and restoration mechanism, and a contention resolution scheme. In this paper, we focus on the burst assembly mechanism. We present a novel data burst generation algorithm that uses hysteresis characteristics in the queueing model for the ingress edge node in optical burst switching networks. Simulation with Poisson and self‐similar traffic models shows that this algorithm adaptively changes the data burst size according to the offered load and offers high average data burst utilization with a lower timer operation. It also reduces the possibility of a continuous blocking problem in the bandwidth reservation request, limits the maximum queueing delay, and minimizes the required burst size by lifting up data burst utilization for bursty input IP traffic. 相似文献
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A framework for optical burst switching network design 总被引:2,自引:0,他引:2
We analyze optical burst switching (OBS) systems. The analysis leads to a framework which provides guidelines for OBS design. We identify conditions for OBS feasibility and the relationship between burst size, or equivalently burst assembly delay, and throughput, taking into consideration control packet processing and the number of available wavelengths per fiber 相似文献
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光突发交换(OBS)技术集成光电路交换和光分组交换的优势,能满足现有大容量、高速率的多媒体信息交换与传输,将成为下一代光IP骨干网的核心技术。本文详细论述了OBS网络中的关键技术———突发分组的组装技术的各种策略与实现方式,指出具有良好QoS保证又可降低可操控性的突发组装策略将成为最佳选择。 相似文献
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光纤传输技术和光网络技术的发展使得光网络成为现代高速宽带网络的基础骨干网。光突发交换是一种介于光路交换和光分组交换之间的很有发展潜力的交换模式,它结合了两者的优势又克服了两者的缺点。重点阐述了光突发交换的概念和关键技术,并介绍了光突发交换目前的研究进展。 相似文献
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Optical burst switching for service differentiation in thenext-generation optical Internet 总被引:1,自引:0,他引:1
In an effort to eliminate the electronic bottleneck, new optical switches/routers (hardware) are being built for the next-generation optical Internet where IP runs over an all-optical WDM layer. However, important issues yet to be addressed in terms of protocols (software) are how to develop a new paradigm that does not require any buffer at the WDM layer, as in circuit switching, and elimination of any layers between which exist mainly due to historical reasons. At the same time, such a paradigm should also efficiently support bursty traffic with high resource utilization as in packet switching. This article surveys design issues related to a new switching paradigm called optical burst switching, which achieves a balance between circuit and packet switching while avoiding their shortcomings. We describe how OBS can be applied to the next-generation optical Internet, and in particular how offset times and delayed reservation can help avoid the use of buffer, and support quality of service at the WDM layer 相似文献
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To date, optical burst switching (OBS) schemes assume the switch reconfiguration time to be negligible, a part of the processing delay of the control packet, or a fixed value added to the data burst length, regardless of the switch status. In this paper, we show that the switching overhead can have a significant impact on the performance of some OBS channel scheduling schemes. We have also proposed methods to alleviate the problem 相似文献
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Optical switching technology can be categorized into optical circuit switching (OCS), optical packet switching (OPS) and optical burst switching (OBS). OCS is suitable for large amounts of data transmission; however, the channel utilization is inefficient when the traffic flows are intermittent. OPS can be easily adapted to any higher layer and is suitable for bursty traffic, but it requires a highly complex technology and optical buffer. The new switching paradigm, OBS, can provide higher bandwidth utilization and meanwhile avoid the complexity in OPS technology.In this paper, we investigate how the quality of service (QoS) can be guaranteed and reliable transmission can be supported in the OBS-based Internet backbone. We propose the adjustable-time-counter-based (ATCB) burst assembly and the non-real time packet retransmission mechanisms and apply them in the ingress router of the OBS Internet backbone to guarantee the quality of real time applications and lossless requirement of non-real time services. Moreover, traffic shaped is performed for real time packets in the egress router so that the real time property is preserved with a low jitter. Simulation results show that the burst blocking probability using the ATCB burst assembly is improved, compared with the time-counter-based (TCB) and burst-length-threshold-based (BLTB) mechanisms. The delay, loss and jitter of real time service conform to the QoS requirement. Meanwhile, the delay of non-real time service also falls in the acceptable range. 相似文献
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Optical burst switching (OBS) presents itself as a promising technology for bridging the gap between optical wavelength switching
and optical packet switching. Increasingly, researchers attempt to incorporate more realistic constraints into the design
of OBS networks. Optical signal transmission quality is subject to various types of physical impairment introduced by optical
fibers, switching equipment, or other network components. The signal degradation due to physical impairments may be significant
enough such that the bit-error rate of received signals is unacceptably high at the destination, rendering the signal not
usable. In this paper, based on earlier work, we study the burst scheduling problem in OBS networks, taking into account physical
impairment effects. We propose three effective burst scheduling algorithms: (1) a JET based Physical Impairment Constrained
Algorithm (JETPIC), (2) an Integrated Physical Impairment Constrained Algorithm (IPIC), and (3) an Enhanced Integrated Physical
Impairment Constrained Algorithm (EIPIC). At an OBS node, the proposed algorithms schedule bursts for transmission by searching
for available resources as well as verifying signal quality. Our simulation results show that the proposed algorithms are
effective in terms of reducing the burst blocking probability. In general, algorithm JETPIC outperforms algorithms IPIC and
EIPIC in burst blocking probability and average end-to-end delay performance.
相似文献
Bin WangEmail: |
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Optical burst switching (OBS) is regarded as one of the most promising switching technologies for next generation optical
networks. However, the data burst contention problem is still unresolved thoroughly even though slotted OBS (SOBS) is studied
as a new paradigm reducing the blocking rate. In this article, we propose a tree-based slot allocation (TSA) algorithm for
loss-free SOBS networks, where the TSA algorithm originally avoids contention of the time-slots by reserving the time-slots
with different time-slot positions for the source nodes, respectively. In order to manage the time-slots efficiently, we also
propose an OBS superframe, which is a cyclic period and consists of multiple time-slots transmitted by the source nodes toward
the same incoming port of a destination node. In addition, we attempt to optimize multiplexing of the OBS superframes to reduce
wavelength consumption. On the other hand, when incoming traffic is beyond expectation, a source node may need more time-slots
to prevent packet loss because of buffer overflow. For reallocation of the time-slots, we propose a flow control scheme managing
some number of shared time-slots, where a control node adaptively allocates (or redeems) the time-slots to (or from) source
nodes by utilizing the shared time-slots based on fluctuating traffic condition. Simulation results show that the blocking
rate of the proposed TSA–OBS scheme is zero with acceptable queueing delay at moderate traffic offered loads. In addition,
multiplexing optimization simulated in the 14-node NSFNET achieves a 63% reduction of wavelength consumption. Moreover, the
proposed flow control scheme assisting the TSA algorithm maintains a target upper-bound of queueing delay at the source node,
so that packet loss caused by buffer overflow is prevented. 相似文献
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光突发交换网络基于优先级与突发包分割的光缓存方法 总被引:2,自引:1,他引:1
为了保证光突发交换(OBS)网络中不同优先级业务的服务质量(Qos)和有效地降低突发包的丢失率,提出了一种基于优先级与突发包分割的光缓存方法.该方法通过在输出数据信道上设置光纤延迟线组来缓存被分割的冲突突发包.当冲突发生时,基于突发包的优先级进行"竞争突发包头部分割或者原突发包尾部分割,,处理;无冲突部分进行交换或者直... 相似文献