Wavelength assignment for parallel FFT communication pattern on linear arrays by lattice embedding

©2005 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.Fast Fourier Transform(FFT) represents a common communication pattern shared by a large class of scientific and engineering problems and wavelength assignment is a key issue to increase efficiency and reduce cost in Wavelength Division Multiplexing (WDM) optical networks. In this paper, we propose a new scheme for the wavelength assignment of parallel FFT communication pattern on WDM linear arrays. By lattice embedding, the number of wavelengths required to realize parallel FFT communication pattern on WDM linear arrays significantly improves the known result. Our proposed embedding method also provides a new approach to the hypercube layout problem considering connections dimension by dimension rather than all connections as in the traditional approach.Yawen Chen, Hong She

High speed all optical networks

An inherent problem of conventional point-to-point wide area network (WAN) architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. The first solution to wavelength division multiplexing (WDM) based WAN networks that overcomes this limitation is presented. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs. The principle of the Lightnet architecture is the construction and use of virtual topology networks, embedded in the original network in the wavelength domain. For this construction Lightnets utilize the new concept of lightpaths which constitute the links of the virtual topology. Lightpaths are all-optical, multihop, paths in the network that allow data to be switched through intermediate nodes using high throughput passive optical switches. The use of the virtual topologies and the associated switching design introduce a number of new ideas, which are discussed in detail

Optical control plane: theory and algorithms

In this thesis we propose a novel way to achieve global network information dissemination in which some wavelengths are reserved exclusively for global control information exchange. We study the routing and wavelength assignment problem for the special communication pattern of non-blocking all-to-all broadcast in WDM optical networks. We provide efficient solutions to reduce the number of wavelengths needed for non-blocking all-to-all broadcast, in the absence of wavelength converters, for network information dissemination. We adopt an approach in which we consider all nodes to be tap-and-continue capable thus studying lighttrees rather than lightpaths. To the best of our knowledge, this thesis is the first to consider “tap-and-continue” capable nodes in the context of conflict-free all-to-all broadcast. The problem of all to-all broadcast using individual lightpaths has been proven to be an NP-complete problem [6]. We provide optimal RWA solutions for conflict-free all-to-all broadcast for some particular cases of regular topologies, namely the ring, the torus and the hypercube. We make an important contribution on hypercube decomposition into edge-disjoint structures. We also present near-optimal polynomial-time solutions for the general case of arbitrary topologies. Furthermore, we apply for the first time the “cactus” representation of all minimum edge-cuts of graphs with arbitrary topologies to the problem of all-to-all broadcast in optical networks. Using this representation recursively we obtain near-optimal results for the number of wavelengths needed by the non-blocking all-to-all broadcast. The second part of this thesis focuses on the more practical case of multi-hop RWA for non- blocking all-to-all broadcast in the presence of Optical-Electrical-Optical conversion. We propose two simple but efficient multi-hop RWA models. In addition to reducing the number of wavelengths we also concentrate on reducing the number of optical receivers, another important optical resource. We analyze these models on the ring and the hypercube, as special cases of regular topologies. Lastly, we develop a good upper-bound on the number of wavelengths in the case of non-blocking multi-hop all-to-all broadcast on networks with arbitrary topologies and offer a heuristic algorithm to achieve it. We propose a novel network partitioning method based on “virtual perfect matching” for use in the RWA heuristic algorithm

Efficient embedding of virtual hypercubes in irregular WDM optical networks

This thesis addresses one of the important issues in designing future WDM optical networks. Such networks are expected to employ an all-optical control plane for dissemination of network state information. It has recently been suggested that an efficient control plane will require non-blocking communication infrastructure and routing techniques. However, the irregular nature of most WDM networks does not lend itself to efficient non-blocking communications. It has been recently shown that hypercubes offer some very efficient non-blocking solutions for, all-to-all broadcast operations, which would be very attractive for control plane implementation. Such results can be utilized by embedding virtual structures in the physical network and doing the routing using properties of a virtual architecture. We will emphasize the hypercube due to its proven usefulness. In this thesis we propose three efficient heuristic methods for embedding a virtual hypercube in an irregular host network such that each node in the host network is either a hypercube node or a neighbor of a hypercube node. The latter will be called a “satellite” or “secondary” node. These schemes follow a step-by-step procedure for the embedding and for finding the physical path implementation of the virtual links while attempting to optimize certain metrics such as the number of wavelengths on each link and the average length of virtual link mappings. We have designed software that takes the adjacency list of an irregular topology as input and provides the adjacency list of a hypercube embedded in the original network. We executed this software on a number of irregular networks with different connectivities and compared the behavior of each of the three algorithms. The algorithms are compared with respect to their performance in trying to optimize several metrics. We also compare our algorithms to an already existing algorithm in the literature

Some studies on the multi-mesh architecture.

In this thesis, we have reported our investigations on interconnection network architectures based on the idea of a recently proposed multi-processor architecture, Multi-Mesh network. This includes the development of a new interconnection architecture, study of its topological properties and a proposal for implementing Multi-Mesh using optical technology. We have presented a new network topology, called the 3D Multi-Mesh (3D MM) that is an extension of the Multi-Mesh architecture [DDS99]. This network consists of n3 three-dimensional meshes (termed as 3D blocks), each having n3 processors, interconnected in a suitable manner so that the resulting topology is 6-regular with n6 processors and a diameter of only 3n. We have shown that the connectivity of this network is 6. We have explored an algorithm for point-to-point communication on the 3D MM. It is expected that this architecture will enable more efficient algorithm mapping compared to existing architectures. We have also proposed some implementation of the multi-mesh avoiding the electronic bottleneck due to long copper wires for communication between some processors. Our implementation considers a number of realistic scenarios based on hybrid (optical and electronic) communication. One unique feature of this investigation is our use of WDM wavelength routing and the protection scheme. We are not aware of any implementation of interconnection networks using these techniques.Dept. of Computer Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .A32. Source: Masters Abstracts International, Volume: 43-03, page: 0868. Adviser: Subir Bandyopadhyay. Thesis (M.Sc.)--University of Windsor (Canada), 2004

Parallel routing and wavelength assignment for optical multistage interconnection networks

Multistage interconnection networks (MINs) are among the most efficient switching architectures in terms of the number of switching elements (SEs) used. For op-tical MINs (OMINs), two I/O connections with neigh-boring wavelengths cannot share a common SE due to crosstalk. In this paper, we focus on the wavelength di-lation approach, in which the I/O connections shar-ing a common SE will be assigned different wavelengths with enough wavelength spacing. We first study the per-mutation capacity of OMINs, then propose fast par-allel routing and wavelength assignment algorithms for OMINs. By applying our permutation decomposi-tion and graph coloring techniques, the proposed algo-rithms can route any permutation without crosstalk in wavelength-rearrangeable space-strict-sense Banyan net-works and wavelength-rearrangeable space-rearrangeable Benes networks in polylogarithmic time using a linear num-ber of processors. 1

Modular expansion and reconfiguration of shufflenets in multi-star implementations.

by Philip Pak-tung To.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 57-60).Chapter 1 --- Introduction --- p.1Chapter 2 --- Modular Expansion of ShuffleNet --- p.8Chapter 2.1 --- Multi-Star Implementation of ShuffleNet --- p.10Chapter 2.2 --- Modular Expansion of ShuffleNet --- p.21Chapter 2.2.1 --- Expansion Phase 1 --- p.21Chapter 2.2.2 --- Subsequent Expansion Phases --- p.24Chapter 2.3 --- Discussions --- p.26Chapter 3 --- Reconfigurability of ShuffleNet in Multi-Star Implementation --- p.33Chapter 3.1 --- Reconfigurability of ShuffleNet --- p.34Chapter 3.1.1 --- Definitions --- p.34Chapter 3.1.2 --- Rearrangable Conditions --- p.35Chapter 3.1.3 --- Formal Representation --- p.38Chapter 3.2 --- Maximizing Network Reconfigurability --- p.40Chapter 3.2.1 --- Rules to maximize Tsc and Rsc --- p.41Chapter 3.2.2 --- Rules to Maximize Z --- p.42Chapter 3.3 --- Channels Assignment Algorithms --- p.43Chapter 3.3.1 --- Channels Assignment Algorithm for w = p --- p.45Chapter 3.3.2 --- Channels Assignment Algorithm for w = p. k --- p.46Chapter 3.3.3 --- Channels Assignment Algorithm for w=Mpk --- p.49Chapter 3.4 --- Discussions --- p.51Chapter 4 --- Conclusions --- p.5

Real-Time Energy Price-Aware Anycast RWA for Scheduled Lightpath Demands in Optical Data Center Networks

The energy consumption of the data center networks and the power consumption associated with transporting data to the users is considerably large, and it constitutes a significant portion of their costs. Hence, development of energy efficient schemes is very crucial to address this problem. Our research considers the fixed window traffic allocation model and the anycast routing scheme to select the best option for the destination node. Proper routing schemes and appropriate combination of the replicas can take care of the issue for energy utilization and at the same time help diminish costs for the data centers. We have also considered the real-time pricing model (which considers price changes every hour) to select routes for the lightpaths. Hence, we propose an ILP to handle the energyaware routing and wavelength assignment (RWA) problem for fixed window scheduled traffic model, with an objective to minimize the overall electricity costs of a datacenter network by reducing the actual power consumption, and using low-cost resources whenever possible

Performance analysis on multi-dimensional optical routing networks.

Zhang Yu.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 67-72).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Overview of Optical Networking --- p.1Chapter 1.2 --- Mechanism in Optical Routing Networks --- p.3Chapter 1.3 --- Related Work on Optical Routing Networks --- p.4Chapter 1.4 --- The Motivation of This Thesis --- p.7Chapter 1.5 --- Thesis Structure --- p.8Chapter 2 --- Technologies for Multi-dimensional Optical Routing Networks --- p.10Chapter 2.1 --- Background --- p.10Chapter 2.2 --- Multi-fiber WDM Networks --- p.11Chapter 2.2.1 --- Phased-Array-Based WDM Device --- p.11Chapter 2.2.2 --- Wavelength-tunable lasers --- p.11Chapter 2.2.3 --- Tunable optical Filter --- p.12Chapter 2.2.4 --- Wavelength Converter --- p.13Chapter 2.3 --- OCDM/WDM --- p.16Chapter 2.3.1 --- Optical En/Decoder --- p.17Chapter 2.3.2 --- Optical Switch --- p.18Chapter 2.3.3 --- Optical Code Conversion --- p.18Chapter 2.4 --- OTDM/WDM --- p.21Chapter 2.4.1 --- Fast Optical Switch --- p.22Chapter 2.4.2 --- Optical Time Slot Interchanger (OTSI) --- p.22Chapter 2.5 --- Conclusion --- p.23Chapter 3 --- Performance of Code/Wavelength Routing Networks --- p.24Chapter 3.1 --- Background --- p.24Chapter 3.2 --- Reconfiguration Capability --- p.25Chapter 3.3 --- Analytic Models --- p.27Chapter 3.3.1 --- Trunk Switched Model --- p.27Chapter 3.3.2 --- Assumptions --- p.28Chapter 3.3.3 --- Blocking of the Paths with Various Configurations --- p.29Chapter 3.4 --- Numerical Results --- p.34Chapter 3.5 --- Conclusion --- p.35Chapter 4 --- Decomposition Schemes --- p.40Chapter 4.1 --- Introduction --- p.40Chapter 4.2 --- Inclusive Converted Networks --- p.41Chapter 4.3 --- Decompositions --- p.43Chapter 4.3.1 --- Spatial Decomposition (S.D.) --- p.43Chapter 4.3.2 --- Dimensional Decomposition (D.D.) --- p.44Chapter 4.3.3 --- Iterative Decompositions --- p.45Chapter 4.4 --- Conclusion --- p.46Chapter 5 --- Performance of Multi-Dimensional Optical Routing Networks --- p.48Chapter 5.1 --- Homogeneous Trunk Switched Networks --- p.48Chapter 5.2 --- Analytical Model --- p.49Chapter 5.3 --- Utilization Gain --- p.53Chapter 5.4 --- Conversion Gain --- p.54Chapter 5.5 --- Comparison on the Utilization Gain by Multiplexing and by Conversion --- p.56Chapter 5.6 --- Conclusion --- p.57Chapter 6 --- Conclusion --- p.65Chapter 6.1 --- Summary of the Thesis --- p.65Chapter 6.2 --- Future Work --- p.6