A Shared-Path Shared-Compute Planning Strategy for a Resilient Hybrid C-RAN

One key challenge in 5G networks is to guarantee the survivability of services in the event of failures. This paper focuses on the hybrid cloud radio access network (H-CRAN) architecture. The proposed strategy guarantees survivability in the presence of failures affecting nodes/links in the midhaul segment (i.e., connecting the radio aggregation unit (RAU) nodes to their respective radio cloud center (RCC) nodes) as well as compute resources (i.e., servers) in the RCC nodes. In the envisioned strategy each RAU node is connected to a primary and a backup RCC node (i.e., with backup compute resources) via two node disjoint connectivity paths in the midhaul. The proposed strategy, called Shared-Path Shared-Compute Planning (SPSCP), lowers the overall design cost by trying to share as much as possible backup connectivity and compute resources among RAU nodes. This is made possible by introducing a shareability metric early into the RCC node selection process so that the chance of sharing backup resources is maximized. Simulation results show that the SPSCP strategy can lead to up to 28% cost savings when compared to conventional resilient design strategie

Hospital Governance, Performance Objectives, and Organizational Form

This paper studies the governance of a sample of California hospitals. We document a number of empirical relations about hospital governance: The composition of the board of directors varies systematically across ownership types; poor performance and low levels of uncompensated care increase board turnover, with this sensitivity varying by organizational type. Poor performance, high administrative costs, and high uncompensated care lead to higher CEO turnover, with these effects again varying across different organizational types. Overall, these results are consistent with the view that boards of directors of hospitals of different organizational forms are substantially different, and that these boards make decisions to maximize different objective functions.

Protection strategies for next generation passive optical networks -2

Next Generation Passive Optical Networks-2 (NGPON2) are being considered to upgrade the current PON technology to meet the ever increasing bandwidth requirements of the end users while optimizing the network operators' investment. Reliability performance of NG-PON2 is very important due to the extended reach and, consequently, large number of served customers per PON segment. On the other hand, the use of more complex and hence more failure prone components than in the current PON systems may degrade reliability performance of the network. Thus designing reliable NG-PON2 architectures is of a paramount importance. Moreover, for appropriately evaluating network reliability performance, new models are required. For example, the commonly used reliability parameter, i.e., connection availability, defined as the percentage of time for which a connection remains operable, doesn't reflect the network wide reliability performance. The network operators are often more concerned about a single failure affecting a large number of customers than many uncorrelated failures disconnecting fewer customers while leading to the same average failure time. With this view, we introduce a new parameter for reliability performance evaluation, referred to as the failure impact. In this paper, we propose several reliable architectures for two important NGPON2 candidates: wavelength division multiplexed (WDM) PON and time and wavelength division multiplexed (TWDM) PON. Furthermore, we evaluate protection coverage, availability, failure impact and cost of the proposed schemes in order to identify the most efficient protection architecture

End-to-End Provisioning of Latency and Availability Constrained 5G Services

We address a key challenge of 5G networks by proposing a strategy for the resource-efficient and end-to-end allocation of compute and connectivity resources in a dynamic 5G service provisioning scenario, such that the service latency and availability requirements are guaranteed. Our heuristic algorithm shows that resource efficiency is significantly improved by processing services in the large core data centers (DCs) with a rich amount of compute resources and exploiting the benefits of traffic grooming over the metro and core fiber links. Moreover, our resource-efficient provisioning algorithm avoids possible violation of the service availability requirements caused by reaching the central DC locations by adding backup connectivity resources. Our simulation results demonstrate a resource efficiency improvement reflected by lowering the service blocking probability by up to four orders of magnitude compared to the conventional service provisioning methods utilizing distributed small DCs

Планування матеріально-технічного постачання підприємства

Despite their intrinsic power efficiency, transparent wavelength division multiplexing (WDM) networks have additional potentials to save energy, and have attracted the interest of researchers with many power-aware (PA) routing and wavelength assignment (RWA) solutions being proposed in the literature. These approaches seem to have, however, an adverse effect on network blocking probability performance. This paper aims at providing a different insight to the PA-RWA problem. The idea is based on the intuition that power minimization and resource blocking can be jointly treated. The proposed approach, called Weighted Power-Aware RWA (WPA-RWA), has been tested using a continental core network and the performance evaluation confirms the presence of a trade-off between power saving and blocking probability.© 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. QC 20120202</p

RECODIS : Resilient communication services protecting end-user applications from disaster-based failures

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Eavesdropping G.652 vs. G.657 fibres: a performance comparison

With increasing dependence on secure access to digital services and the ultra-high traffic volumes running on the optical fibre communication infrastructure, the protection of this infrastructure from eavesdropping is extremely important, especially in defense and military applications. The G.657 fibre is recommended to be deployed in in-building installations for its improved bending performance compared to the G.652 fibre. However, the easiness to be eavesdropped, which reflects the security level of those two types of fibres has not yet been investigated. In this paper, we study the eavesdropping of fibre from a system perspective and compare the bending property of G.652 and G.657 fibres. The measurement results show that G.657 can be bent sharper than G.652 without causing any additional power attenuation at the receiver. This indicates that the so-called bending-insensitive G.657 fibre can potentially be eavesdropped more easily than their G.652 counterparts. The paper also shows that the power level measurement at the receiver may not be sufficient for unambiguous eavesdrop detection

Educational pedagogical and adaptational work with international students and preparatory department attendees of Pavlo Tychyna Uman State Pedagogical University

To address the sustainability, scalability, and reliability problems that data centers are currently facing, we propose three passive optical interconnect (POI) architectures on top of the rack. The evaluation results show that all three architectures offer high reliability performance (connection availability for intra-rack interconnections higher than 99.999%) in a cost-efficient way.QC 20160525</p

Enabling Technologies for Optical Data Center Networks: Spatial Division Multiplexing

With the continuously growing popularity of cloud services, the traffic volume inside the\ua0data\ua0centers is dramatically increasing. As a result, a scalable and efficient infrastructure\ua0for\ua0data\ua0center\ua0networks\ua0(DCNs) is required. The current\ua0optical\ua0DCNs using either individual fibers or fiber ribbons are costly, bulky, hard to manage, and not scalable.\ua0Spatial\ua0division\ua0multiplexing\ua0(SDM) based on multicore or multimode (few-mode) fibers is recognized as a promising technology to increase the\ua0spatial\ua0efficiency\ua0for\ua0optical\ua0DCNs, which opens a new way towards high capacity and scalability. This tutorial provides an overview of the components, transmission options, and interconnect architectures\ua0for\ua0SDM-based DCNs, as well as potential technical challenges and future directions. It also covers the co-existence of SDM and other\ua0multiplexing\ua0techniques, such as wavelength-division\ua0multiplexing\ua0and flexible spectrum\ua0multiplexing, in\ua0optical\ua0DCNs