WDM Metro Networks

2021 ◽  
pp. 321-370
Author(s):  
Debasish Datta

With increasing traffic, legacy SONET/SDH-metro rings have mostly been upgraded using point-to-point WDM (PPWDM) transmission. For cost-effective realization, WDM metro networks also employ wavelength-routed optical networking (WRON), where a wavelength is bypassed optically at intermediate nodes. Metro networks are generally split into core and edge rings, with the metro-core ring interfacing with the long-haul backbone and the metro-edge ring interconnecting the metro-core ring with the access segment. The PPWDM/WRON transmission is employed with each wavelength using circuit-switched SONET/SDH transmission, though the metro-edge rings can also use packet-switching to enhance bandwidth utilization with bursty traffic from the access segment. In this chapter, we consider first WDM metro networks using PPWDM/WRON-based rings and present their design methodologies using LP-based and heuristic schemes. We describe some packet-switched WDM ring testbeds and examine the possible improvement in bandwidth utilization therein, as compared to the circuit-switched WRON rings. (143 words)

2020 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Alessandro Scano ◽  
Robert Mihai Mira ◽  
Pietro Cerveri ◽  
Lorenzo Molinari Tosatti ◽  
Marco Sacco

In the field of motion analysis, the gold standard devices are marker-based tracking systems. Despite being very accurate, their cost, stringent working environments, and long preparation time make them unsuitable for small clinics as well as for other scenarios such as industrial application. Since human-centered approaches have been promoted even outside clinical environments, the need for easy-to-use solutions to track human motion is topical. In this context, cost-effective devices, such as RGB-Depth (RBG-D) cameras have been proposed, aiming at a user-centered evaluation in rehabilitation or of workers in industry environment. In this paper, we aimed at comparing marker-based systems and RGB-D cameras for tracking human motion. We used a Vicon system (Vicon Motion Systems, Oxford, UK) as a gold standard for the analysis of accuracy and reliability of the Kinect V2 (Microsoft, Redmond, WA, USA) in a variety of gestures in the upper limb workspace—targeting rehabilitation and working applications. The comparison was performed on a group of 15 adult healthy subjects. Each subject had to perform two types of upper-limb movements (point-to-point and exploration) in three workspace sectors (central, right, and left) that might be explored in rehabilitation and industrial working scenarios. The protocol was conceived to test a wide range of the field of view of the RGB-D device. Our results, detailed in the paper, suggest that RGB-D sensors are adequate to track the upper limb for biomechanical assessments, even though relevant limitations can be found in the assessment and reliability of some specific degrees of freedom and gestures with respect to marker-based systems.


2003 ◽  
Vol 02 (04) ◽  
pp. 403-408
Author(s):  
A. Al-Zoubaidi

In this paper we propose a Regional Internet Exchange (RIX) scheme for MENA countries intra-regional traffic, compared with the existing situation for Internet service provision. The RIX architecture is proposed, implemented, and evaluated using simulation. Simultaneous comparative performance evaluation of Internet service provision for the existing and the proposed scenarios are presented. It is focused to measure utilization, message delays, access time and client perceived latencies performance metrics. The study shows that the proposed scheme results in less international bandwidth utilization and it reduces significantly the access time and most importantly it is inherently cost-effective.


Author(s):  
Laura Martín González ◽  
Sjoerd van der Heide ◽  
Xuwei Xue ◽  
John van Weerdenburg ◽  
Nicola Calabretta ◽  
...  

Adaptive Sliceable-Bandwidth Variable Transceivers (S-BVTs) are key enabler for future optical networks. In particular, those based on Discrete MultiTone (DMT) modulation and Direct Detection (DD) can be considered a flexible solution suitable to address the cost efficiency requirement of optical metro networks. In this paper, we propose to use this cost-effective S-BVT option/implementation in optical metro networks adopting switching nodes based on Semiconductor Optical Amplifier (SOA) technology. Bit loading (BL) and power loading (PL) algorithms are applied to the Digital Signal Processing (DSP) modules, to maximize the performance and/or the capacity as well as enhance the flexibility and adaptability of the system. Our analysis considers switching nodes based on SOAs with and without filtering elements and fiber spans of 25 km. We present the results up to 100 km, with and without SOA-based nodes. Firstly, we analyze the adaptive BVT transmission using the Margin Adaptive (MA) BL/PL algorithm at a fixed bit rate of 28 Gb/s. The possibility of controlling the SOAs current is a key factor to face the transmission impairments due to the fiber and the filtering elements. We also analyze the system considering Rate Adaptive (RA) transmission at a fixed target BER of 3.8·10−3, showing that a maximum capacity above 34 Gb/s can be achieved for a single span of 25 km. Although the cascading of filtering elements still constitutes a limiting factor, we show that an improvement of the net bit rate performance can be obtained thanks to the combined use of S-BVT and SOA technology at the switching nodes, resulting in a promising approach for designing future optical metro networks.


Author(s):  
Vaibhav Shukla ◽  
Aruna Jain

Optical packet switching is connectionless networking solution through which we can get high speed data transfer and optimum bandwidth utilization using wavelength division multiplexing technique. For realizing optical packet switching the numbers of optical packet switch architectures are available in market. In this chapter the authors discuss the overall development of optical packet switching; some recently published optical packet switch architectures are discussed in the chapter and a comparison is performed between the switches through loss, cost and buffer analysis.


2014 ◽  
Vol 936 ◽  
pp. 2344-2351 ◽  
Author(s):  
Duan Feng Han ◽  
Hany Abdelkhalek ◽  
Miao Chen

This paper presents an overview of ship general arrangement design methodologies and philosophies and early-stage design capabilities, particularly during the last decade. The arrangement of a ship has a unique feature in that it can both enable successful shipboard operations and constrain the performance of all subsystems. Stable ship layout is critical to producible, and therefore cost effective, designs and time. This paper overviews the efforts made by the researchers in the last decade to improve generating the arrangement rapidly . Also, identify areas of the ship general arrangements process that are insufficiently addressed or not addressed at all in order to keep pushing the field of general arrangements forward.


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