Next Generation Optical Access Networks: from TDM to WDM

Postprint (author’s final draft

Algoritmo distribuido para la asignación dinámica de recursos en redes EPON

Peer ReviewedPostprint (published version

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Enhanced DBA to provide QoS to coexistent EPON and 10G-EPON networks

The evolution of the Ethernet passive optical network (EPON) to the enhanced 10G-EPON standard looks poised to maintain its position as the leading fiber to the home technology worldwide. Fair bandwidth allocation will be a challenge in the near future in plants where 1G and 10G customer premises equipment coexists. In this paper we propose a distributed algorithm, distributed dynamic scheduling for EPON (DDSPON), to dynamically allocate the bandwidth requested by the user equipment with quality of service (QoS) constraints. The proposed algorithm is scalable and simple to re-configure, which facilitates a smoother transition from legacy 1G to 10G networks. By using the DDSPON, enhanced optical network units (ONUs) will take full advantage of the 10 Gb/s rate while legacy 1G ONUs maintain their service level agreement; as a result, the individual performance is maximized for both groups of ONUs. We also present an analytical model to evaluate the algorithm performance in a coexistent 1G/10G network. Finally, we also illustrate the enhancement of the DDSPON to provision the QoS to different services under the DiffServ architecture. Analysis and simulation results validate the effectiveness of the proposed mechanisms.Peer ReviewedPostprint (author’s final draft

Flexible joint scheduling DBA to promote the fair coexistence in 1G and 10G EPONs

The Next Generation Access Networks (NGAN) are the new step forward to deliver broadband services and to facilitate the integration of different technologies. The real challenge faced by 10GEPON new standard IEEE 803.3av is to upgrade the channel capacity for both upstream and downstream channels gracefully, while maintaining the logical layer intact ensuring the coexistence with legacy 1 Gb/s (IEEE 802.3ah). The Dynamic Bandwidth Allocation (DBA) for the upstream shared channel is a key issue. We propose in this paper a distributed DBA-Distributed Dynamic Scheduling for EPON, (DDSPON)-that allows the coexistence among both standards in such mixed architecture. In particular, we remark that, by using the enhanced DDSPON, the new standardized optical network units (ONUs) will take full advantage of the enhanced rate at 10 Gb/s while the legacy 1 Gb/s ONUs keep a good performance, and thus allowing a fair coexistence of both groups of ONUs-legacy and 10 Gb/s-, and even though the individual performance is maximized, no matter the group being evaluated. We compare DDSPON with another well-known scheduling algorithm and we show that it performs better specially when the traffic is bursty. Furthermore, the proposed algorithm is scalable, simple to re-configure, and cost-effective, which facilitates a smoother transition from 1G to 10G EPON.Peer ReviewedPostprint (published version

Enhanced DBA to provide QoS to coexistent EPON and 10G-EPON networks

The evolution of the Ethernet passive optical network (EPON) to the enhanced 10G-EPON standard looks poised to maintain its position as the leading fiber to the home technology worldwide. Fair bandwidth allocation will be a challenge in the near future in plants where 1G and 10G customer premises equipment coexists. In this paper we propose a distributed algorithm, distributed dynamic scheduling for EPON (DDSPON), to dynamically allocate the bandwidth requested by the user equipment with quality of service (QoS) constraints. The proposed algorithm is scalable and simple to re-configure, which facilitates a smoother transition from legacy 1G to 10G networks. By using the DDSPON, enhanced optical network units (ONUs) will take full advantage of the 10 Gb/s rate while legacy 1G ONUs maintain their service level agreement; as a result, the individual performance is maximized for both groups of ONUs. We also present an analytical model to evaluate the algorithm performance in a coexistent 1G/10G network. Finally, we also illustrate the enhancement of the DDSPON to provision the QoS to different services under the DiffServ architecture. Analysis and simulation results validate the effectiveness of the proposed mechanisms.Peer Reviewe

Flexible joint scheduling DBA to promote the fair coexistence in 1G and 10G EPONs

The Next Generation Access Networks (NGAN) are the new step forward to deliver broadband services and to facilitate the integration of different technologies. The real challenge faced by 10GEPON new standard IEEE 803.3av is to upgrade the channel capacity for both upstream and downstream channels gracefully, while maintaining the logical layer intact ensuring the coexistence with legacy 1 Gb/s (IEEE 802.3ah). The Dynamic Bandwidth Allocation (DBA) for the upstream shared channel is a key issue. We propose in this paper a distributed DBA-Distributed Dynamic Scheduling for EPON, (DDSPON)-that allows the coexistence among both standards in such mixed architecture. In particular, we remark that, by using the enhanced DDSPON, the new standardized optical network units (ONUs) will take full advantage of the enhanced rate at 10 Gb/s while the legacy 1 Gb/s ONUs keep a good performance, and thus allowing a fair coexistence of both groups of ONUs-legacy and 10 Gb/s-, and even though the individual performance is maximized, no matter the group being evaluated. We compare DDSPON with another well-known scheduling algorithm and we show that it performs better specially when the traffic is bursty. Furthermore, the proposed algorithm is scalable, simple to re-configure, and cost-effective, which facilitates a smoother transition from 1G to 10G EPON.Peer Reviewe

Real-time services in EPON

This paper proposes an improved scheduling algorithm that optimizes the allocation of the real-time services and elastic flows in EPON by spreading the real-time service periods lowering the delay and thus fulfilling the QoS requirements.Peer ReviewedPostprint (author’s final draft

Real-time services in EPON

This paper proposes an improved scheduling algorithm that optimizes the allocation of the real-time services and elastic flows in EPON by spreading the real-time service periods lowering the delay and thus fulfilling the QoS requirements.Peer Reviewe

Algoritmo distribuido para la asignación dinámica de recursos en redes EPON

Peer Reviewe