Optimal multicast routing using genetic algorithm for WDM optical networks

We consider the multicast routing problem for large-scale wavelength division multiplexing (WDM) optical networks where transmission re-quests are established by point-to-multipoint connections. To realize multicast routing in WDM optical networks, some nodes need to havelight (optical) splitting capability. A node with splitting capability can forward an incoming message to more than one output link. We con-sider the problem of minimizing the number of split-capable nodes in the network for a given set of multicast requests. The maximum number of wavelengths that can be used is specified a priori. A genetic algorithm is proposed that exploits the combination of alternative shortest paths for the given multicast requests. This algorithm is examined for two realis-tic networks constructed based on the locations of major cities in Ibaraki Prefecture and those in Kanto District in Japan. Our experimental re-sults show that the proposed algorithm can reduce more than 10% of split-capable nodes compared with the case where the split-capable node placement optimization is not performed while the specified number of wavelengths is not exceeded.Includes bibliographical reference

Super monitor design for fast link failure localization in all-optical networks

Monitoring cycle (m-cycle) based design is cost efficient for fast link failure detection and localization in all-optical networks. An m-cycle is an optical loop-back pre-cross-connection of a supervisory wavelength with a dedicated monitor. Generally, a simple monitor is placed at an arbitrary node of an m-cycle for supervision. In this paper, we propose a novel monitor structure, called super monitor. A super monitor is used to supervise multiple intersecting cycles and placed at the intersection node. For a given set of m-cycles, we use super monitors to replace some (or all) simple monitors that originally locate in the set. Two major advantages of the super monitor are: 1) it has lower hardware cost; 2) the collocation of monitoring devices reduces the management cost simultaneously. Besides, the super monitor does not incur additional bandwidth cost. We formulate an integer linear program (ILP) to solve the problem of monitor placement. Numerical results show that our ILP can efficiently place the monitors with a significantly minimized monitoring cost. © 2011 IEEE.published_or_final_versionThe 2011 IEEE International Conference on Communications (ICC 2011), Kyoto, Japan, 5-9 June 2011. In Proceedings of the IEEE ICC, 2011, p. 1-

Optical Networks and Interconnects

The rapid evolution of communication technologies such as 5G and beyond, rely on optical networks to support the challenging and ambitious requirements that include both capacity and reliability. This chapter begins by giving an overview of the evolution of optical access networks, focusing on Passive Optical Networks (PONs). The development of the different PON standards and requirements aiming at longer reach, higher client count and delivered bandwidth are presented. PON virtualization is also introduced as the flexibility enabler. Triggered by the increase of bandwidth supported by access and aggregation network segments, core networks have also evolved, as presented in the second part of the chapter. Scaling the physical infrastructure requires high investment and hence, operators are considering alternatives to optimize the use of the existing capacity. This chapter introduces different planning problems such as Routing and Spectrum Assignment problems, placement problems for regenerators and wavelength converters, and how to offer resilience to different failures. An overview of control and management is also provided. Moreover, motivated by the increasing importance of data storage and data processing, this chapter also addresses different aspects of optical data center interconnects. Data centers have become critical infrastructure to operate any service. They are also forced to take advantage of optical technology in order to keep up with the growing capacity demand and power consumption. This chapter gives an overview of different optical data center network architectures as well as some expected directions to improve the resource utilization and increase the network capacity

Design of power efficient multicast algorithms for sparse split WDM networks

Recent years witnessed tremendous increase in data traffic as new Internet applications were launched. Optical networks employing recent technologies such as DWDM and EDFA`s emerged as the most prominent and most promising solutions in terms of their ability to keep with the demand on bandwidth. However for a class of applications bandwidth is not the only important requirement, These applications require efficient multicast operations. They include data bases, audio/video conferencing, distributed computing etc. Multicasting in the optical domain however has its own unique set of problems. First, an optical signal can be split among the outputs of a node but the power due to splitting can be significantly reduced. Second, the hardware for split nodes is relatively expensive and therefore we cannot afford to employ it at every node. Third, there are other sources of losses such as attenuation losses and multiplexing /de-multiplexing losses. This thesis deals with the important issue of Power Efficient multicast in WDM optical networks. We report three new algorithms for constructing power efficient multicast trees and forests. Our algorithms are the first to take into account all possible sources of power losses while constructing the trees. We utilize the techniques of backtracking and tree pruning judiciously to achieve very power efficient multicast trees. The first two algorithms use modified versions of the shortest path heuristic to build the tree. The third algorithm however, uses a novel concept and considers power at every tree building step. In this algorithm, the order of inclusion of destination nodes into the tree is based on the power distribution in the tree and not distance. All three algorithms prune the trees if the power levels at the destinations are not acceptable. The performance of these three algorithms under several constraints is studied on several irregular topologies. All three algorithms reported in this work produce significant improvements in signal strength at the set of destinations over the existing multicast algorithms. Numerical results show that our third algorithm outperforms the first two algorithms as well as the existing multicasting algorithms

Optical Transport Network Design for 5G Fixed Wireless Access

The fifth generation (5G) of mobile technology, 5G is anticipated to be a significant leap in the evolution of mobile communication. 5G will be designed to attain 1000 times higher data volumes, 10 times lower latency, and 100 times more connected devices than its predecessor, 4G. Due to 5Gs ability to sustain high bandwidth per unit area, 5G is considered to be a cost-efficient solution to provide fixed wireless access (FWA) to households on a large scale. FWA is seen as an attractive alternative for fixed broadband access in scenarios where last mile access based on wired technologies is not economically viable. While approaches for enhancing user experience in a 5G FWA environment are investigated in the research community, the problem of providing cost-effective high capacity transport for FWA deployments still remains a major challenge. This is particularly challenging due to diverse transport network architectures and requirements imposed by different 5G deployment models. This paper addresses this problem by formulating a generalized joint-optimization framework to simultaneously plan wireless access and optical transport for 5G FWA networks in order to minimize the deployment cost while meeting various network requirements. We demonstrate the applicability of the proposed framework by applying it to a real scenario with a range of deployment options and where different types of optical x-haul solutions are considered. The results provide a cornerstone for deployment strategies that will be imperative for realizing a future-proof and cost-effective broadband access network