50,552 research outputs found
A survey on OFDM-based elastic core optical networking
Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed
Redundancy Strategies for a High Splitting Optically Amplified Passive Optical Network
Copyright 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.High splitting, optically amplified, passive optical networks (SuperPONs) are investigated in terms of redundancy provision and protection mechanisms. Options for redundancy, including the important special case of dual homing, are detailed, and it is determined as to which of these options (duplication of the feeder and first distribution section, and N+1 protection of the optical amplifiers in the amplified splitter) would be required to be provided to all attached users to facilitate appropriate availability of the basic telephony service. The distributed amplified splitter dual homing solution is found to outperform the single amplified splitter solution in terms of its survivability. The protection mechanisms necessary to automatically switch to the redundant provision are discussed and it is seen that with the aid of suitable regular precautionary procedures protection switching can generally be provided rapidly (<50 ms). Finally, an availability, and cost versus availability, study confirms the aforementioned redundancy assessment for fiber-to-the-home (FTTH) implementations, but shows fiber-to-the-curb (FTTC) as needing additional redundancyPeer reviewe
Optimized Design of Survivable MPLS over Optical Transport Networks. Optical Switching and Networking
In this paper we study different options for the survivability implementation
in MPLS over Optical Transport Networks in terms of network resource usage and
configuration cost. We investigate two approaches to the survivability
deployment: single layer and multilayer survivability and present various
methods for spare capacity allocation (SCA) to reroute disrupted traffic. The
comparative analysis shows the influence of the traffic granularity on the
survivability cost: for high bandwidth LSPs, close to the optical channel
capacity, the multilayer survivability outperforms the single layer one,
whereas for low bandwidth LSPs the single layer survivability is more
cost-efficient. For the multilayer survivability we demonstrate that by mapping
efficiently the spare capacity of the MPLS layer onto the resources of the
optical layer one can achieve up to 22% savings in the total configuration cost
and up to 37% in the optical layer cost. Further savings (up to 9 %) in the
wavelength use can be obtained with the integrated approach to network
configuration over the sequential one, however, at the increase in the
optimization problem complexity. These results are based on a cost model with
actual technology pricing and were obtained for networks targeted to a
nationwide coverage
Software defined networking: meeting carrier grade requirements
Software Defined Networking is a networking paradigm which allows network operators to manage networking elements using software running on an external server. This is accomplished by a split in the architecture between the forwarding element and the control element. Two technologies which allow this split for packet networks are ForCES and Openflow. We present energy efficiency and resilience aspects of carrier grade networks which can be met by Openflow. We implement flow restoration and run extensive experiments in an emulated carrier grade network. We show that Openflow can restore traffic quite fast, but its dependency on a centralized controller means that it will be hard to achieve 50 ms restoration in large networks serving many flows. In order to achieve 50 ms recovery, protection will be required in carrier grade networks
Optical Network Models and their Application to Software-Defined Network Management
Software-defined networking is finding its way into optical networks. Here,
it promises a simplification and unification of network management for optical
networks allowing automation of operational tasks despite the highly diverse
and vendor-specific commercial systems and the complexity and analog nature of
optical transmission. A fundamental component for software-defined optical
networking are common abstractions and interfaces. Currently, a number of
models for optical networks are available. They all claim to provide open and
vendor agnostic management of optical equipment. In this work, we survey and
compare the most important models and propose an intent interface for creating
virtual topologies that is integrated in the existing model ecosystem.Comment: Parts of the presented work has received funding from the European
Commission within the H2020 Research and Innovation Programme, under grant
agreeement n.645127, project ACIN
Scalable dimensioning of resilient Lambda Grids
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