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Energy efficiency is well-known to have recently become one of the most important aspects for both today's and tomorrow's telecommunications infrastructures. To curb their energy requirements, next-generation hardware platforms of network devices are expected to include advanced power management capabilities, which may allow a dynamic trade-off between power consumption and network performance. At...
In this paper, we propose low complexity bit rate variable transponders for adaptive DC biased Optical OFDM systems. The transponders are based on an alternative transform, the fast Hartley transform (FHT), and use adaptively modulated O-OFDM (AMO-OFDM) to introduce flexibility to optical networks. Additionally, low complexity selective mapping (LC-SLM) technique is included in the bit rate variable...
Network operators are migrating to a multi-layer architecture with IP/MPLS equipment and optical nodes. Thanks to the advent of reconfigurable optical equipment and a multilayer control plane, current 1+1 node protection at the IP layer in each location is not required anymore. This work studies the network availability in a national network with current 1+1 protection. To do so, an analytical expression...
The evolution from point-to-point Dense Wavelength Division Multiplexing (DWDM) systems towards Wavelength-Switched Optical Networks (WSON) was mainly driven by the consolidation of all-optical technology such as the Reconfigurable Optical Add-Drop Multiplexer (ROADM) and the Optical Cross-Connect (OXC). These network nodes are capable of routing and switching in the optical domain, avoiding the expensive...
In this paper we focus on 1+1 dedicated protection in multi-layer network formed by Connection-Oriented (CO) Ethernet over Wavelength Switched Optical Networks (WSON) under the framework of a GMPLS control plane. We propose a dynamic path computation algorithm that is used for computing both the working and protecting paths, ensuring the Shared Risk Link Group (SRLG) disjointness at both layers. The...
With the continuing growth of traffic, improving the flexibility and the transparency of optical networks are very important challenges that operators have to face. In this paper, we present a networking technique based on optical multi-band Orthogonal Frequency Division Multiplexing. The optical multi-band OFDM approach enables optical switching at fine granularity in a highly spectrum-efficient...
A characterization of a phase modulated coherent optical OFDM system based on Hartley transform is performed. The use of phase modulation minimizes OFDM amplitude fluctuations, resulting in reduced peak-to-average power ratio. Also, it is based on Hartley transform for simplifying the signal processing. In this paper, theoretical models are developed for describing the behavior of the system when...
We propose Energy Watermark Algorithm (EWA), an adaptive algorithm to reduce power consumption in Internet Protocol (IP)-over-Wavelength Division Multiplexing (WDM) networks. Our solution wisely adapts the set of powered on line cards to the actual traffic demand. In particular, EWA trades between network power consumption and Quality of Service (QoS) by changing the level of overprovisioning of the...
This paper analyzes the performance of an optical packet switch architecture with highly distributed control, designed for interconnection of cluster switches in a simulated data center traffic environment. The system under development can be scaled up to a very large ports count, in the thousand order, enabling interconnection of a great number of servers. An important feature of this optical packet...
Recently, an improved receiving technique for Optical Wireless (OW) with Intensity Modulation and Direct Detection (IM-DD) communication systems, implementing Asymmetrically-Clipped Optical OFDM (ACO-OFDM) modulation, has been proposed. It uses the previously discarded (so called in the literature) “clipping noise” to generate an improved estimator for the transmitted signal, up to 3dB in the receiver...
A novel all-optical OFDM demultiplexer based on integrated photonic ring resonators (RR) is proposed and its performance validated. The proposed optical OFDM demultiplexer overcome the processing speed limits introduced by electronics and is suitable for very large scale integration, providing a compact and cost-effective solution. The performance of this device considering a Silicon-on-Insulator...
The OpenFlow concept was recently proposed primarily to facilitate policy routing in large enterprise/service provider networks. Carrier Ethernet technologies such as MPLS-TP and PBB-TE are currently considered to be the forerunners in such transport networks. Both these technologies specify the need for a managed control plane. Carrier Ethernet Switch Routers (CESRs) are being proposed for transport...
So far latency has been regarded as a minor issue in Passive Optical Networks (PONs). However it may become a key factor for the commercial success of PON and WDM-PON. In this work we review the relevance of very-low latency in the access as the enabler of new higly-interactive cloud services. Then, we propose an approach for delay-based differentiation in PON that causes the delay variance to become...
OCDMA over conventional TDM PON leads to increase access network capacity by multiplexing TDM signals with OCDMA codes. We propose a novel sourceless ONU for OCDMA-TDM PON within a centralized light source placed at OLT. Sparser and longer extended quadratic congruence (EQC) codes with good correlation properties are used as optical CDMA en/decoders. However, multiple access interference (MAI) can...
Nowadays the ubiquity of telecommunication networks, which underpin and fulfill key aspects of modern day living, is taken for granted. Significant large-scale failures have occurred in the last years affecting telecommunication networks. Traditionally, network robustness analysis has been focused on topological characteristics. Recently approaches also consider the services supported by such networks...
We study the design of virtual optical bus (VOB) network, which has been recently proposed as a packet-oriented all-optical solution for transport networks. Design of a VOB network consists of grouping all edge-to-edge flows in the network into clusters called VOBs and that has to be done with the objective of minimizing packet collision rate in the optical network. We present an efficient heuristic...
In this paper a new heuristic algorithm for cost-effective lightpath assignment in mixed line rates WDM networks based on a light trail architecture is proposed. The algorithm improves the performance of a previous heuristic by exploiting the volume discount provided by high-rate lightpaths and the ability of longer paths to groom future traffic demands. Results show that the proposed algorithm is...
Spectrum-sliced elastic optical path (SLICE) technology offers a more flexible bandwidth allocation in optical networks than wavelength division multiplexing. It allows different connections to be served via different modulation formats. However, as with any optical network, the optical signal may be susceptible to signal impairments, especially when the signal traverses over long distances. The degree...
Several approaches exist to categorize power savings in Information and Communication Technologies (ICT) networks. In this paper we survey current power saving techniques in backbone telecommunication networks, based on an analytical power model. This categorization allows for a more intuitive understanding of the power saving potential of different approaches, and shows that in order to achieve large...
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