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1.
Optical packet switching (OPS) is a promising technology to enable next-generation high-speed IP networks. A major issue in
OPS is packet contention that occurs when two or more packets attempt to access the same output fiber. In such a case, packets
may be dropped, leading to degraded overall switching performance. Several contention resolution techniques have been investigated
in the literature including the use of fiber delay lines (FDLs), wavelength converters (WCs), and deflection routing. These
solution typically induce extra complexity to the switch design. Accordingly, a key design objective for OPS is to reduce
packet loss without increasing switching complexity and delay. In this paper, we investigate the performance of contention
resolution in asynchronous OPS architectures with shared FDLs and WCs in terms of packet loss and average switching delay.
In particular, an enhanced FDL-based and a novel Hybrid architecture with shared FLDs and WCs are proposed, and their packet scheduling algorithms are presented and evaluated. Extensive
simulation studies show that the performance of proposed FDL-based architecture outperforms typical OPS architectures reported
in the literature. In addition, it shown that, for the same packet loss ratio, the proposed hybrid architecture can achieve
up to 30% reduction in the total number of ports and around 80% reduction in the overall length of fiber as compared to the
FDL-based architectures. 相似文献
2.
ZhangZhizhong ChengFang ZhaoHuandong ZengQingji 《电子科学学刊(英文版)》2005,22(4):333-344
This paper investigates the untraditional approach of contention resolution in Wavelength Division Multiplexing (WDM) Optical Packet Switching (OPS). The most striking characteristics of the developed switch architecture are: (1) Contention resolution is achieved by a combined sharing of Fiber Delay-Lines (FDLs) and Tunable Optical Wavelength Converters (TOWCs); (2) FDLs are arranged in non-degenerate form, i.e., non-uniform distribution of the delay lines; (3) TOWCs just can perform wavelength conversion in partial continuous wavelength channels, i.e., sparse wavelength conversion. The concrete configurations of FDLs and TOWCs are described and analyzed under non-bursty and bursty traffic scenarios. Simulation results demonstrate that for a prefixed packet loss probability constraint, e.g., 10-6, the developed architecture provides a different point of view in OPS design. That is, combined sharing of FDLs and TOWCs can, effectively, obtain a good tradeoff between the switch size and the cost, and TOWCs which are achieved in sparse form can also decrease the implementing complexity. 相似文献
3.
《Photonics Technology Letters, IEEE》2008,20(18):1581-1583
4.
Harald Øverby 《Photonic Network Communications》2007,13(2):183-194
Optical packet switching (OPS) has emerged as a promising architecture for the future all-optical network scenario. In order
to have a successful deployment of OPS networks, several networking issues must be resolved, e.g., how to resolve contentions
and how to provide Quality-of-Service (QoS) differentiation. Such networking studies often rely on teletraffic analysis in
order to quantify the performance of the OPS network. In this paper, we introduce new and review existing traffic models for
slotted buffer-less OPS networks. In particular, we present a novel asymmetric traffic model, suitable for studying the effects
of non-uniform traffic. Optical packet switches with and without wavelength conversion are studied. Numerical evaluations
and a comparison study of the presented traffic models are reported. The main contributions of this paper are to advance the
field of establishing a theoretical framework for slotted OPS networks and to act as a tutorial for teletraffic engineering
in such networks.
http://www.item.ntnu.no/~haraldov. 相似文献
5.
Masoud Asghari Jamshid Bagherzadeh Saleh Yousefi 《Photonic Network Communications》2018,35(2):274-286
Artificial neural networks (ANNs) are well-known estimators for the output of broad range of complex systems and functions. In this paper, a common ANN architecture called multilayer perceptron (MLP) is used as a fast optical packet loss rate (OPLR) estimator for bufferless optical packet-switched (OPS) networks. Considering average loads at the ingress switches of an OPS network, the proposed estimator estimates total OPLR as well as ingress OPLRs (the OPLR of optical packets sent from individual ingress switches). Moreover, a traffic policing algorithm called OPLRC is proposed to control ingress OPLRs in bufferless slotted OPS networks with asymmetric loads. OPLRC is a centralized greedy algorithm which uses estimated ingress OPLRs of a trained MLP to tag some optical packets at the ingress switches as eligible for drop at the core switches in case of contention. This will control ingress OPLRs of un-tagged optical packets within the specified limits while giving some chance for tagged optical packets to reach their destinations. Eventually, the accuracy of the proposed estimator along with the performance of the proposed algorithm is evaluated by extensive simulations. In terms of the algorithm, the results show that OPLRC is capable of controlling ingress OPLRs of un-tagged optical packets with an acceptable accuracy. 相似文献
6.
Architecture, design, and modeling of the OPSnet asynchronous optical packet switching node 总被引:3,自引:0,他引:3
An all-optical packet-switched network supporting multiple services represents a long-term goal for network operators and service providers alike. The EPSRC-funded OPSnet project partnership addresses this issue from device through to network architecture perspectives with the key objective of the design, development, and demonstration of a fully operational asynchronous optical packet switch (OPS) suitable for 100 Gb/s dense-wavelength-division multiplexing (DWDM) operation. The OPS is built around a novel buffer and control architecture that has been shown to be highly flexible and to offer the promise of fair and consistent packet delivery at high load conditions with full support for quality of service (QoS) based on differentiated services over generalized multiprotocol label switching. 相似文献
7.
Choo Peng Tan Gerardo Castañón Su Fong Chien Ah Heng You Andy Lock Yen Low 《Photonic Network Communications》2006,12(3):257-268
This paper studies several buffering strategies for optical packet switching (OPS) under limited packet sorting. Three schemes, which are able to sort newly arrived packets based on packet’s length as well as capability of finding the minimum buffer occupancy, are analyzed and compared. Results show that all three proposed schemes could improve OPS performance considerably in terms of probability of packet loss (PPL) and probability of information loss (PIL). In addition, the simulation results show that not all the newly arrived packets need to be sorted in order to obtain minimum packet loss probability. Since the amount of packets and thus the packet processing time is significant in OPS, it is possible that not all the packets can be processed using one of the buffering strategies. An important finding of this paper is that if only 10% of the packets are sorted, the PPL is comparable to the minimum packet loss value obtained when 100% of the packets are sorted. 相似文献
8.
A novel optical buffering architecture for Optical Packet Switching (OPS) networks is proposed in this article. The architecture
which adopts a fiber-sharing mechanism aims at solving the problem of using a large number of fiber delay lines that are used
to solve resource contention in the core node in OPS networks. The new architecture employs fewer fiber delay lines compared
to other simple architectures, but can achieve the same performance. Simulation results and analysis show that the new architecture
can decrease packet loss probability effectively and achieve reasonable performance in average packet delay.
相似文献
Fang GuoEmail: |
9.
Because pure electrical routers with their bandwidth limitations can hardly keep up with the tremendous traffic growth in the Internet, optical routers based on various optical switching techniques including optical wavelength switching (OWS), optical burst switching (OBS), and optical packet switching (OPS) have been suggested to cope with this problem. However, because OBS and OPS are both in their early experimental phase and OWS only provides coarse granularity switching, a hybrid-switching optical router with combined OWS and electrical packet switching is a necessity in order to accommodate the entire multi-granularity traffic with multi-service requirements in a cost-effective manner. Its coordination capability of optical circuit switching and electrical packet switching enables efficient/intelligent usage of network resources. In this paper, we first review research and developments of such IP routers employing optical switching/interconnection techniques and examine how these techniques can be used inside routers to scale node capacity and to improve optical Internet performance. We also present and study the performance of a terabit optical router with an optical-electrical hybrid-switching fabric. The node architecture is based on the idea of IP over WDM integration with Generalized Multi-Protocol Label Switching (GMPLS). The network-level performance evaluations show that the proposed hybrid-switching optical router is a cost-effective solution for building the next generation GMPLS-based multi-granularity optical Internet. 相似文献
10.
A novel architecture of optical code (OC) label generation and recognition for optical packet switching (OPS) by using super structured fiber Bragg grating (SSFBG) is proposed.The OC label is generated and recognized by a label generator and recognizer,respectively.The label generator is composed of N encoders in parallel,and it can generate 2N kinds of serial optical code labels (SOCLs) for indicating 2N network routing information.The label recognizer can decode SOCLs by N decoders in parallel and provides label information to the switching control unit so that clock information is not required during the decoding process.In the switch nodes,handling of the high-speed information payload stream and the recognition of the OC label are performed in the optical domain,while processing of the routing information remains in the electrical domain.This approach could be a promising solution for an OPS network with high capacity,good quality of service (QoS),multi-service function and high security.In this experiment,we demonstrate 40Gbps 256 label optical packet switching that employs clockless SOCL processing. 相似文献
11.
Indayara Bertoldi Martins Felipe Rudge Barbosa Luiz Henrique Bonani Edson Moschim 《Photonic Network Communications》2012,24(3):187-197
Photonic switching for traffic optimization in Metropolitan Access Optical Networks using technologies of optical packet/burst switching (OPS/OBS) seems to be a future-proof solution considering high capacity and the highly variable traffic in these networks. Looking for this future, we propose a study based on the analyze of survivability of traffic unconsidering protection mechanism but considering mesh and ring efficient topologies with node architecture to OPS. The results are obtained through computer modeling and simulation. The main parameters analyzed are as follows: capacity, average number of hops, packet loss fraction, and link utilization for each topology. These parameters are adopted to evaluate the performance of each topology considering failures. Minimum electronic buffering is included at node ingress (client side) to avoid packet loss in the access to the optical layer: high throughput and low latency. It is also observed that optical buffering is not necessary for adequate network performance. 相似文献
12.
Develder Chris Houdt Benny Van Blondia Chris Pickavet Mario Demeester Piet 《Photonic Network Communications》2004,8(2):149-161
The major goal of optical packet switching (OPS) is to match switching technology to the huge capacities provided by (D)WDM. A crucial issue in packet switched networks is the avoidance of packet losses stemming from contention. In OPS, contention can be solved using a combination of exploitation of the wavelength domain (through wavelength conversion) and buffering. To provide optical buffering, fiber delay lines (FDLs) are used. In this paper, we focus on an optical packet switch with recirculating FDL buffers and wavelength converters. We introduce the Markovian arrival process with marked transitions (MMAP), which has very desirable properties as a traffic model for OPS performance assessment. Using this model, we determine lower and upper bounds for the packet loss rate (PLR) achieved by the aforementioned switch. The calculation of the PLR bounds through matrix analytical methods is repeated for a wide range of traffic conditions, including highly non-uniform traffic, both in space (i.e., packet destinations) and time (bursty traffic). The quality of these bounds is verified through comparison with simulation results. 相似文献
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15.
核心通信网的光分组交换 总被引:1,自引:0,他引:1
文章首先简单说明了新一代通信网需要使用分级交换的由来。接着详细叙述了光分组交换在未来光通信网的应用,包括节点结构、分组格式、输入、输出接口和一些特别重要的技术,如再生、同步、信头处理、缓冲、空间交换和波长转换等。 相似文献
16.
Unavailability analysis of long-haul networks 总被引:5,自引:0,他引:5
Network survivability is a key concern in today's network, and will become increasingly important in future optical networks as they carry ever more traffic. Networks are also becoming more complex, with the requirement for increased functionality. Currently, there is a lack of understanding in the industry as to the exact relationship between the choice of network architecture and the meeting of a set availability objective. This paper analyses a number of long-haul network architectures from an unavailability point of view. The long-haul networks analyzed include: networks with diversity, networks with restoration capability, and networks with survivability. Derivations are given for each architecture; formulas for 2 and 4-fiber rings, and dual fed routing are new. A hypothetical reference connection (HRX) and its unavailability objectives are used as references. Networks with restoration capability and networks with survivability meet the proposed objective. Self-healing rings (both 2 and 4-fiber bidirectional line switched rings) and dual fed systems offer the highest level of survivability, by eliminating service impacts caused by cable cuts and equipment failures 相似文献
17.
Mobile systems are evolving into data centric, packet switched,multiacess networks. New types of security threats are emerging in thesenew networks. From the user point of view a seamless solution for thesethreats is required. This paper presents a vision of network convergenceand its implications to authentication and authorization solutions.Security requirements are discussed and current authentication solutionsin GSM, UMTS and operator wireless local area networks (OWLAN) areintroduced. All-IP multimedia session security is discussed.Implications of AdHoc network architecture into security requirement arediscussed. 相似文献
18.
Hung Nguyen Tan Nattapong Kitsuwan Motoharu Matsuura Naoto Kishi Eiji Oki 《Optical Switching and Networking》2012,9(4):336-342
We demonstrate in an experiment an optical packet switching (OPS) using recursive parametric wavelength converters (PWCs) which uses the combination of two or more PWCs for wavelength conversions. The PWCs, which are based on four-wave mixing in highly nonlinear fibers, are possible for multiple wavelength conversion, allowing a share-per-node switching scheme, and thus significantly reducing the number of wavelength converters. Detailed demonstration of a developed OPS prototype using the joint of two PWCs indicates the generation of various wavelength conversion patterns which play an important role for OPS performance. The converted signals after two stages of PWC are obtained with error-free operations and low power penalties (BER=10?9) of about 2.0 dB. Numerical results also show significant improvement in packet blocking probability by the proposed recursive PWC-based OPS in comparison with the previous non-recursive schemes. 相似文献
19.
20.
Scheduling Algorithms for a Slotted Packet Switch with either Fixed or Variable Length Packets 总被引:3,自引:2,他引:1
Callegati F. Cerroni W. Corazza G. Develder C. Pickavet M. Demeester P. 《Photonic Network Communications》2004,8(2):163-176
We address the problem of congestion resolution in optical packet switching (OPS). We consider a fairly generic all-optical packet switch architecture with a feedback optical buffer constituted of fiber delay lines (FDL). Two alternatives of switching granularity are addressed for a switch operating in a slotted transfer mode: switching at the slot level (i.e., fixed length packets of a single slot) or at the burst level (variable length packets that are integer multiples of the slot length). For both cases, we show that in spite of the limited queuing resources, acceptable performance in terms of packet loss can be achieved for reasonable hardware resources with an appropriate design of the time/wavelength scheduling algorithms. Depending on the switching units (slots or bursts), an adapted scheduling algorithm needs to be deployed to exploit the bandwidth and buffer resources most efficiently. 相似文献