Adaptive Probabilistic Flooding for Multipath Routing

In this work, we develop a distributed source routing algorithm for topology discovery suitable for ISP transport networks, that is however inspired by opportunistic algorithms used in ad hoc wireless networks. We propose a plug-and-play control plane, able to find multiple paths toward the same destination, and introduce a novel algorithm, called adaptive probabilistic flooding, to achieve this goal. By keeping a small amount of state in routers taking part in the discovery process, our technique significantly limits the amount of control messages exchanged with flooding -- and, at the same time, it only minimally affects the quality of the discovered multiple path with respect to the optimal solution. Simple analytical bounds, confirmed by results gathered with extensive simulation on four realistic topologies, show our approach to be of high practical interest.Comment: 6 pages, 6 figure

First experimental demonstration of real-time orchestration in a Multi-head metro network

International audienceWe present for the first time the experimental demonstration of a Real-Time control-plane on the Multi-hEad sub-wavElength swiTching (MEET), Metro architecture. The key control assets are calculated and provided to the edge nodes in a form of grant files. These grant files eliminate the contention possibility at source nodes and destinations, thus they offer a lossless passive optical grooming and multiplexing/demultiplexing at the intermediate nodes. The experimental results validate the control plane structure designed based on a deterministic operating system well scalable for a regional metro network

FIB Aplasia through Probabilistic Routing and Autoforwarding

In this work, we propose Aplasia, an holistic architecture with a radical design. Aiming at simplifying the inner network devices (and so their cost), we tradeoff node architecture- and algorithmic-complexity for an increased (but tunable) communication cost. The main ingredients of our recipe are (i) the use of complete paths directly in the frames header, that allows core devices to perform data-plane switching functions without lookup and (ii) the use of a greedy probabilistic routing algorithm to quickly discover multiple, near optimal, paths in the control plane. We extensively simulate, analyze and implement our proposal to testify its soundness

LOCARN: Low Opex Capex Architecture for Resilient Networks

Best Paper AwardInternational audienc

Towards a Large Scale LOCARN Design

International audienc

LOCARN: Low Opex Capex Architecture for Resilient Networks

Best Paper AwardInternational audienc

Challenges of 40/100 Gbps and higher-rate deployments over long-haul transport networks

International audienceThe 40/100 Gbps solutions are finally mature for WDM transmission on legacy system and fiber infrastructure of incumbent carriers, which want to upgrade their core and metropolitan transport networks beyond 10 Gbps. One technology, based on the combination of PM-QPSK modulation format, coherent detection and digital signal processing, has solved the dilemma of ultra high bit rate transmission over PMD-limited fiber infrastructure, which has postponed during 10 years 40/100 Gbps deployments. But already, in the R&D laboratories, people start to prepare the next generation of long-distance WDM systems operating at 400 Gbps and 1 Tbps per wavelength.The challenges of 40/100 Gbps deployments on existing system and fiber infrastructure are discussed here, while the most efficient economical conditions for their introduction are determined. The different options for 400 Gbps and 1 Tbps WDM transmissions are compared, while the technical requirements which would allow transporting 50 Tbps overall capacity on more than 1500 km are introduced. The potential consequences of this unbelievable increase of the data rate over the operation of metropolitan and core transport networks are also given, whereas solutions to manage them while increasing the flexibility of these networks are proposed

Dependence of Type Ia supernova luminosities on their local environment

We present a fully consistent catalog of local and global properties of host galaxies of 882 Type Ia supernovæ (SNIa) that were selected based on their light-curve properties, spanning the redshift range 0.01 < z < 1. This catalog corresponds to a preliminary version of the compilation sample and includes Supernova Legacy Survey (SNLS) 5-year data, Sloan Digital Sky Survey (SDSS), and low-redshift surveys. We measured low- and moderate-redshift host galaxy photometry in SDSS stacked and single-epoch images and used spectral energy distribution fitting techniques to derive host properties such as stellar mass and U - V rest-frame colors; the latter are an indicator of the luminosity-weighted age of the stellar population in a galaxy. We combined these results with high-redshift host photometry from the SNLS survey and thus obtained a consistent catalog of host stellar masses and colors across a wide redshift range. We also estimated the local observed fluxes at the supernova location within a proper distance radius of 3 kpc, corresponding to the SNLS imaging resolution, and transposed them into local U - V rest-frame colors. This is the first time that local environments surrounding SNIa have been measured at redshifts spanning the entire Hubble diagram. Selecting SNIa based on host photometry quality, we then performed cosmological fits using local color as a third standardization variable, for which we split the sample at the median value. We find a local color step significance of - 0.091 ± 0.013 mag (7σ), which effect is as significant as the maximum mass step effect. This indicates that the remaining luminosity variations in SNIa samples can be reduced with a third standardization variable that takes the environment into account. Correcting for the maximum mass step correction of - 0.094 ± 0.013 mag, we find a local color effect of - 0.057 ± 0.012 mag (5σ), which shows that additional information is provided by the close environment of SNIa. Departures from the initial choices were investigated and showed that the local color effect is still present, although less pronounced. We discuss the possible implications for cosmology and find that using the local color in place of the stellar mass results in a change in the measured value of the dark energy equation-of-state parameter of 0.6%. Standardization using local U - V color in addition to stretch and color reduces the total dispersion in the Hubble diagram from 0.15 to 0.14 mag. This will be of tremendous importance for the forthcoming SNIa surveys, and in particular for the Large Synoptic Survey Telescope (LSST), for which uncertainties on the dark energy equation of state will be comparable to the effects reported here

Multi-band OFDM transmission at 100 Gbps with sub-band optical switching

International audienceIn this paper, we present an original work on sub- wavelength optical switching performed over a coherent multi- band orthogonal frequency-division multiplexing (MB-OFDM) super-channel operating at 100 Gbps. After having demonstrated that dual-polarization MB-OFDM (DP-MB-OFDM) is as efficient as single-carrier dual-polarization quaternary phase shift keying (DP-QPSK) technology to transport 100 Gbps data-rate over a 10 × 100-km G.652 fiber-based transmission line, we show that opti- cal add-drop of OFDM sub-bands as narrow as 8 GHz inside a 100 Gbps DP-MB-OFDM signal constituted of four sub-bands is fea- sible in the middle of this 1000-km transmission line. The flexible optical add-drop multiplexer (FOADM) implemented here is con- stituted by the association of an ultra-narrow pass-band and stop- band optical filter. The design and realization of such ultra-selective optical filters is presented, while the impact of their physical fea- tures over the quality of transmission is discussed. To prove that several add-drop multiplexers can be cascaded, our FOADM is in- troduced into a G.652 fiber-based recirculating loop and the impact of the cumulated filtering transfer function as well as the crosstalk inside the OADM are investigated. A typical use case for the in- troduction of such FOADM into long-haul transport networks is given, and the capital expenditure (CAPEX) cost advantage for the multi-layer transport networks is highlighted. By the proof of concept delivered here, combination of super-channel and sub- wavelength optical switching pushes network flexibility far away of what is today proposed by system vendors, opening new horizons for an optimized use of multi-layer transport networks