多波长光网络的动态路由等效算法

针对多波长光网络的特点，提出了一种动态路由和波长分配的等效算法。采用波长图、增加虚拟源节点和目的节点等技术，把多波长网络转化为等效的单波长网络，避免了求解路由和波长分配两个复杂子问题，简化了算法的程序设计。利用最短径算法进行路由和波长分配可以求得问题的最优解，从而有效地降低了网络阻塞率。仿真结果表明：与FAR-2D算法相比，在4和8波长的全波长转换网络中，采用等效算法阻塞率最大降幅分别达到0．02、0．025。     

一种新型IP OVER WDM城域网的节点结构

提出了一种基于波分复用（WDM）,分组交换,副载波复用和波长变换技术的新型全光城域网节点结构,网络拓扑采用环形,网络节点采用可调输出固定输入的选波原则以利于数据的多重接入,副载波复用和基于级联半导体光放大器的波长变换,实现了射频副载波路由信息与基带IP数据包的同步复用和IP数据包的透明传输。     

MEMS光开关应用于机群系统光互连网络

建立了千兆位传输结构的高性能光互连网络 ,以提高计算机机群系统的网络性能 .利用MEMS 4× 4光开关和具有硬件路由功能的光互连网络PCI总线接口卡构成光互连链路 .光信号传输速率达 1Gbits/s以上 .基于MEMS的全光无堵塞光开关减少了光 电转换 ,开关方式与光信号的波长、速率和数据格式无关 .利用这种网络结构 ,可以最大限度地减少网络延迟和网络通信开销 ,提升了机群系统的总体性能 .利用MEMS 8× 8光开关设计了星型环型混合拓扑的光互连网络 .采用了具有硬件路由功能的光互连网络接口卡 ,并以Ethernet为控制网络实现了对MEMS光开光的动态配置 .分析并测试了光互连网络的通信性能 :峰值数据传输率可达 1Gbits/s ;数据量在 3Mbytes以上时 ,网络整体性能明显提高     

光互连网络中排序算法研究

通过对光互连网络排序算法的研究,提出利用二分法构造二分图依次确定内外节点开关的连接状态,得到可重排无阻塞的 Omega 网络, Banyan 网络和 Crossover 光网络,每种光互连网络都可实现 8×8 信号全排列无阻塞的输出和排序。针对二分法互连函数不一致的问题,继而采用优化的 Looping Algorithm 算法,生成路由标签确定各级节点开关的状态,从而得到互连函数相同结构简单性能优越的光网络。     

多纤多波长光网络的动态路由等效算法

针对多光纤多波长光网络的特点,提出了一种动态路由和波长分配的等效算法。采用波长图、增加虚拟源节点和目的节点、引入光纤数量矩阵等技术,把多纤多波长网络转化为等效的单波长网络,大大简化了算法程序的复杂度。采用最短径算法作为算法的基础,可求得每次业务在全网范围内的路由和波长分配的最优解。仿真结果表明,当网络呼叫量为60时,全波长转换情况下,2纤、4纤网络的阻塞率分别为0.1116、4.3×10-5。     

光电信息技术的某些发展前沿

本文着重如下内容 :1.波长路由在光互连中的应用 :提出适用于环网的光互连接口 (OII)组件和波长路由交换器件 (WRS)的设计 .网络为多层结构 ,第一层为λ1子环网 (RSN) ,第二层为λ2 子环网等 ,层间通过 WRS连接 .2 .微机电系统 (MEMS)可能在下一代通信网络中占重要地位 :随着信息技术的发展 ,使微电子信息处理向系统级芯片技术发展 ,从微型化或性能价格比来看 ,把信息获取、处理和执行集成在一起的微机电系统 (MEMS) ,特别是光机电一体化集成芯片 ,或称为微光机电系统 (OpticalMEMS或 MOEMS)是很合理的 .3.结合光通信中 WDM技术的发展 ,研究了用用一块光栅模板在 Tal-bot干涉仪上刻写多种频率的光纤 Bragg光栅 .     

一种可扩展的双层光互连网络设计与分析

本文设计一种具有可扩展性的双层并行光互连网络.顶层为数字路由结点和光网络接口卡组成的星型网,底层为光网络接口卡连接而成的环形网.结点机以及数字路由结点影响网络的性能.结点机的吞吐能力限制了整个网络的吞吐率;扩展PCI总线的位数能够提高光网络接口卡的吞吐速率,采用64bit/66MHz工作模式可获得4.224 Gbps峰值传输速率.网络的实际最大吞吐速率为8.448Gbps,环网内平均延迟2195ns,环网间平均延迟4713 ns.可以采用本文设计的数字路由结点对网络进行低成本级联扩展,扩展后网络性能显著提高.     

Tier_Flat:P2P网络并行模拟器(HiFiP2P)的一种路由算法

为了给P2P网络并行模拟器HiFiP2P提供正确高效的路由,使其能够高效地执行大规模P2P网络并行模拟,基于互联网中的层次路由模型和Flat本地静态路由计算和查找算法,采取边界路由最小化的并行网络拓扑划分机制,设计了Tier_Flat路由算法,用以实现HiFiP2P的远程和本地静态路由,它以最低O((N~4)~(1/3))的空间开销,取得了O(1)的查找效率。结果表明,Tier_Flat路由算法路由计算时间短,路由表内存占用小,路由查询速度快,为HiFiP2P平台的大规模P2P网络并行模拟提供了高效的路由服务。     

一种新型的动态路由和波长分配综合算法

讨论了WDM光网中，在动态业务流量和有限范围波长变换情况下的动态路由和波长分配问题。基于Moone-Dijkstra算法，考虑到动态波长变换的可能和限制，提出了一种新型的、可实现动态最小代价路由和最佳虚波长通道的综合启发式算法(DMC-OVWP)。该算法对路由子问题和波长分配子问题既相互独立，又相互结合，优化了RWA。以中国教育和科研计算机网(CERNET)为拓扑背景，基于本算法进行了计算机仿真，并对实验结果进行了比较分析，证明本算法可充分利用网络信息获取较低的阻塞率。     

传输网络中第三条路由的设备解决方案

本文介绍了传输网络在某一节点建设第三条光缆路由时的设备解决方案。同时对0LP技术、OLP各种实现方式及工程中应注意的事项进行论述。对于利用交叉单元实现第三路由的接入，本文着重阐述了SDH网络及0TN网络光、一电层面交叉技术的实现方式和局限，并最终提出两种技术的应用思路。     

Optical binary de Bruijn networks for massively parallel computing: design methodology and feasibility study

The interconnection network structure can be the deciding and limiting factor in the cost and the performance of parallel computers. One of the most popular point-to-point interconnection networks for parallel computers today is the hypercube. The regularity, logarithmic diameter, symmetry, high connectivity, fault tolerance, simple routing, and reconfigurability (easy embedding of other network topologies) of the hypercube make it a very attractive choice for parallel computers. Unfortunately the hypercube possesses a major drawback, which is the complexity of its node structure: the number of links per node increases as the network grows in size. As an alternative to the hypercube, the binary de Bruijn (BdB) network has recently received much attention. The BdB not only provides a logarithmic diameter, fault tolerance, and simple routing but also requires fewer links than the hypercube for the same network size. Additionally, a major advantage of the BdB network is a constant node degree: the number of edges per node is independent of the network size. This makes it very desirable for large-scale parallel systems. However, because of its asymmetrical nature and global connectivity, it poses a major challenge for VLSI technology. Optics, owing to its three-dimensional and globalconnectivity nature, seems to be very suitable for implementing BdB networks. We present an implementation methodology for optical BdB networks. The distinctive feature of the proposed implementation methodology is partitionability of the network into a few primitive operations that can be implemented efficiently. We further show feasibility of the presented design methodology by proposing an optical implementation of the BdB network.     

Scalable optical hypercube-based interconnection network for massively parallel computing

Two important parameters of a network for massively parallel computers are scalability and modularity. Scalability has two aspects: size and time (or generation). Size scalability refers to the property that the size of the network can be increased with nominal effect on the existing configuration. Also, the increase in size is expected to result in a linear increase in performance. Time scalability implies that the communication capabilities of a network should be large enough to support the evolution of processing elements through generations. A modular network enables the construction of a large network out of many smaller ones. The lack of these two important parameters has limited the use of certain types of interconnection networks in the area of massively parallel computers. We present a new modular optical interconnection network, called an optical multimesh hypercube (OMMH), which is both size and time scalable. The OMMH combines positive features of both the hypercube (small diameter, high connectivity, symmetry, simple routing, and fault tolerance) and the torus (constant node degree and size scalability) networks. Also presented is a three-dimensional optical implementation of the OMMH network. A basic building block of the OMMH network is a hypercube module that is constructed with free-space optics to provide compact and high-density localized hypercube connections. The OMMH network is then constructed by the connection of such basic building blocks with multiwavelength optical fibers to realize torus connections. The proposed implementation methodology is intended to exploit the advantages of both space-invariant free-space and multiwavelength fiber-based optical interconnect technologies. The analysis of the proposed implementation shows that such a network is optically feasible in terms of the physical size and the optical power budget.     

Performance evaluation of massively parallel processing architectures with three-dimensional optical interconnections

We evaluate the performance of three-dimensional optoelectronic computer architectures on the basis of basic database operations and parallel benchmark algorithms for numerical computations. We show that the select and the join database operations can be performed much faster with an optical interconnection network. Also, optoelectronic architectures can perform the fast Fourier transform and sorting benchmarks orders of magnitude faster than electronic supercomputers. An architecture with an adequately fast reconfigurable interconnection network can perform the conjugate-gradient benchmark faster than all parallel supercomputers, but its performance is not as impressive when a fixed network is used. In the case of the multigrid benchmark the three-dimensional optoelectronic architecture also can outperform the best parallel supercomputers.     

Experimental free-space optical network for massively parallel computers

A free-space optical interconnection scheme is described for massively parallel processors based on the interconnection-cached network architecture. The optical network operates in a circuit-switching mode. Combined with a packet-switching operation among the circuit-switched optical channels, a high-bandwidth, low-latency network for massively parallel processing results. The design and assembly of a 64-channel experimental prototype is discussed, and operational results are presented.     

Hierarchical optical ring interconnection (HORN): scalable interconnection network for multiprocessors and multicomputers

A new interconnection network for massively parallel computing is introduced. This network is called a hierarchal optical ring interconnection (HORN). The HORN consists of a single-hop, scalable, constant-degree, strictly nonblocking, fault-tolerant interconnection topology that uses wavelength-division multiple access to provide better utilization of the terahertz bandwidth offered by optics. The proposed optical network integrates the attractive features of hierarchical ring interconnections, e.g., a simple node interface, a constant node degree, better support for the locality of reference, and fault tolerance, with the advantages of optics. The HORN topology is presented, its architectural properties are analyzed, and an optical design methodology for it is described. Furthermore, a brief feasibility study of the HORN is conducted. The study shows that the topology is highly amenable to optical implementation with commercially available optical elements.     

Multichip free-space global optical interconnection demonstration with integrated arrays of vertical-cavity surface-emitting lasers and photodetectors

The experimental optical interconnection module of the Free-Space Accelerator for Switching Terabit Networks (FAST-Net) project is described and characterized. Four two-dimensional (2-D) arrays of monolithically integrated vertical-cavity surface-emitting lasers (VCSEL's) and photodetectors (PD's) were designed, fabricated, and incorporated into a folded optical system that links a 10 cm x 10 cm multichip smart pixel plane to itself in a global point-to-point pattern. The optical system effects a fully connected network in which each chip is connected to all others with a multichannel bidirectional data path. VCSEL's and detectors are arranged in clusters on the chips with an interelement spacing of 140 mum. Calculations based on measurements of resolution and registration tolerances showed that the square 50-mum detector in a typical interchip link captures approximately 85% of incident light from its associated VCSEL. The measured optical transmission efficiency was 38%, with the losses primarily due to reflections at the surfaces of the multielement lenses, which were not antireflection coated for the VCSEL wavelength. The overall efficiency for this demonstration is therefore 32%. With the measured optical confinement, an optical system that is optimized for transmission at the VCSEL wavelength will achieve an overall efficiency of greater than 80%. These results suggest that, as high-density VCSEL-based smart pixel technology matures, the FAST-Net optical interconnection concept will provide a low-loss, compact, global interconnection approach for high bisection-bandwidth multiprocessor applications in switching, signal processing, and image processing.     

Dynamic O-band to C-band wideband wavelength converter for integrated VCSEL-based optical interconnects

ABSTRACT

Real-time wavelength conversion and traffic routing at key network nodes is a fundamental requirement for current optical interconnects. This work experimentally demonstrates a broadband wavelength conversion from O-band to C-band employing commercially available, power efficient VCSELs. A 1310?nm VCSEL is directly modulated with 8.5 Gbps data and transmitted over 22?km G. 652 fibre with a 0.53 dB penalty. The received data is used to run a 1550?nm VCSEL located at the network integration node, achieving the first reported wavelength conversion from O-to-C-band. VCSEL wavelength tuneability with changing bias current functionality is further exploited to route the converted wavelength over 400?GHz spectra range for integration into wavelength flexible networks. The newly converted wavelength is transmitted over 24.7?km of G. 655 fibre, incurring a maximum penalty of 1.86?dB. Results from this work proves an enabling development technology for wavelength converters for transparent contention resolution in current and future optical Interconnects.     

Double-layer networks with holographic optical switches

The double-layer networks have the advantages of being strictly nonblocking and having a simpler routing algorithm, the lowest system insertion loss, a zero differential loss, fewer drivers, fewer interconnection lines, fewer crossovers, and the best signal-to-noise-ratio characteristic compared with any nondilated network. Using holographic optical switches to construct these networks not only eliminates all interconnection lines and crossovers but also reduces the number of drivers.