36,083 research outputs found
Experimental Validation of Time-Synchronized Operations for Software-Defined Elastic Optical Networks
Elastic optical networks (EON) have been proposed as a solution to efficiently exploit the spectrum resources in the physical layer of optical networks. Moreover, by centralizing legacy generalized multiprotocol label switching control-plane functionalities and providing a global network view, software-defined networking (SDN) enables advanced network programmability valuable to control and configure the technological breakthroughs of EON. In this paper, we review our recent proposal [Optical Fiber Communication Conf., Los Angeles, California, 2017] of time-synchronized operations (TSO) to minimize disruption time during lightpath reassignment in EON. TSO has been recently standardized in SDN, and here we discuss its implementation using NETCONF and OpenFlow in optical networks. Subsequently, we update our analytical model considering an experimental characterization of the WSS operation time. Then, we extend our previous work with an experimental validation of TSO for lightpath reassignment in a five-node metropolitan optical network test-bed. Results validate the convenience of our TSO-based approach against a traditional asynchronous technique given its reduction of disruption time, while both techniques maintain a similar network performance in terms of optical signal-to-noise ratio and optical power budget
On the Impact of Optimal Modulation and FEC Overhead on Future Optical Networks
The potential of optimum selection of modulation and forward error correction
(FEC) overhead (OH) in future transparent nonlinear optical mesh networks is
studied from an information theory perspective. Different network topologies
are studied as well as both ideal soft-decision (SD) and hard-decision (HD) FEC
based on demap-and-decode (bit-wise) receivers. When compared to the de-facto
QPSK with 7% OH, our results show large gains in network throughput. When
compared to SD-FEC, HD-FEC is shown to cause network throughput losses of 12%,
15%, and 20% for a country, continental, and global network topology,
respectively. Furthermore, it is shown that most of the theoretically possible
gains can be achieved by using one modulation format and only two OHs. This is
in contrast to the infinite number of OHs required in the ideal case. The
obtained optimal OHs are between 5% and 80%, which highlights the potential
advantage of using FEC with high OHs.Comment: Some minor typos were correcte
IDEALIST control and service management solutions for dynamic and adaptive flexi-grid DWDM networks
Wavelength Switched Optical Networks (WSON) were designed with the premise that all channels in a network have the same spectrum needs, based on the ITU-T DWDM grid. However, this rigid grid-based approach is not adapted to the spectrum requirements of the signals that are best candidates for long-reach transmission and high-speed data rates of 400Gbps and beyond. An innovative approach is to evolve the fixed DWDM grid to a flexible grid, in which the optical spectrum is partitioned into fixed-sized spectrum slices. This allows facilitating the required amount of optical bandwidth and spectrum for an elastic optical connection to be dynamically and adaptively allocated by assigning the necessary number of slices of spectrum. The ICT IDEALIST project will provide the architectural design, protocol specification, implementation, evaluation and standardization of a control plane and a network and service management system. This architecture and tools are necessary to introduce dynamicity, elasticity and adaptation in flexi-grid DWDM networks. This paper provides an overview of the objectives, framework, functional requirements and use cases of the elastic control plane and the adaptive network and service management system targeted in the ICT IDEALIST project
An Overview on Application of Machine Learning Techniques in Optical Networks
Today's telecommunication networks have become sources of enormous amounts of
widely heterogeneous data. This information can be retrieved from network
traffic traces, network alarms, signal quality indicators, users' behavioral
data, etc. Advanced mathematical tools are required to extract meaningful
information from these data and take decisions pertaining to the proper
functioning of the networks from the network-generated data. Among these
mathematical tools, Machine Learning (ML) is regarded as one of the most
promising methodological approaches to perform network-data analysis and enable
automated network self-configuration and fault management. The adoption of ML
techniques in the field of optical communication networks is motivated by the
unprecedented growth of network complexity faced by optical networks in the
last few years. Such complexity increase is due to the introduction of a huge
number of adjustable and interdependent system parameters (e.g., routing
configurations, modulation format, symbol rate, coding schemes, etc.) that are
enabled by the usage of coherent transmission/reception technologies, advanced
digital signal processing and compensation of nonlinear effects in optical
fiber propagation. In this paper we provide an overview of the application of
ML to optical communications and networking. We classify and survey relevant
literature dealing with the topic, and we also provide an introductory tutorial
on ML for researchers and practitioners interested in this field. Although a
good number of research papers have recently appeared, the application of ML to
optical networks is still in its infancy: to stimulate further work in this
area, we conclude the paper proposing new possible research directions
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