A Survey on the Path Computation Element (PCE) Architecture

Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multi-domain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits

Research Studies on Advanced Optical Module/Head Designs for Optical Data Storage

Preprints are presented from the recent 1992 Optical Data Storage meeting in San Jose. The papers are divided into the following topical areas: Magneto-optical media (Modeling/design and fabrication/characterization/testing); Optical heads (holographic optical elements); and Optical heads (integrated optics). Some representative titles are as follow: Diffraction analysis and evaluation of several focus and track error detection schemes for magneto-optical disk systems; Proposal for massively parallel data storage system; Transfer function characteristics of super resolving systems; Modeling and measurement of a micro-optic beam deflector; Oxidation processes in magneto-optic and related materials; and A modal analysis of lamellar diffraction gratings in conical mountings

Next generation control of transport networks

It is widely understood by telecom operators and industry analysts that bandwidth demand is increasing dramatically, year on year, with typical growth figures of 50% for Internet-based traffic [5]. This trend means that the consumers will have both a wide variety of devices attaching to their networks and a range of high bandwidth service requirements. The corresponding impact is the effect on the traffic engineered network (often referred to as the “transport network”) to ensure that the current rate of growth of network traffic is supported and meets predicted future demands. As traffic demands increase and newer services continuously arise, novel network elements are needed to provide more flexibility, scalability, resilience, and adaptability to today’s transport network. The transport network provides transparent traffic engineered communication of user, application, and device traffic between attached clients (software and hardware) and establishing and maintaining point-to-point or point-to-multipoint connections. The research documented in this thesis was based on three initial research questions posed while performing research at British Telecom research labs and investigating control of transport networks of future transport networks: 1. How can we meet Internet bandwidth growth yet minimise network costs? 2. Which enabling network technologies might be leveraged to control network layers and functions cooperatively, instead of separated network layer and technology control? 3. Is it possible to utilise both centralised and distributed control mechanisms for automation and traffic optimisation? This thesis aims to provide the classification, motivation, invention, and evolution of a next generation control framework for transport networks, and special consideration of delivering broadcast video traffic to UK subscribers. The document outlines pertinent telecoms technology and current art, how requirements I gathered, and research I conducted, and by which the transport control framework functional components are identified and selected, and by which method the architecture was implemented and applied to key research projects requiring next generation control capabilities, both at British Telecom and the wider research community. Finally, in the closing chapters, the thesis outlines the next steps for ongoing research and development of the transport network framework and key areas for further study

Ecology-based planning. Italian and French experimentations

This paper examines some French and Italian experimentations of green infrastructures’ (GI) construction in relation to their techniques and methodologies. The construction of a multifunctional green infrastructure can lead to the generation of a number of relevant bene fi ts able to face the increasing challenges of climate change and resilience (for example, social, ecological and environmental through the recognition of the concept of ecosystem services) and could ease the achievement of a performance-based approach. This approach, differently from the traditional prescriptive one, helps to attain a better and more fl exible land-use integration. In both countries, GI play an important role in contrasting land take and, for their adaptive and cross-scale nature, they help to generate a res ilient approach to urban plans and projects. Due to their fl exible and site-based nature, GI can be adapted, even if through different methodologies and approaches, both to urban and extra-urban contexts. On one hand, France, through its strong national policy on ecological networks, recognizes them as one of the major planning strategies toward a more sustainable development of territories; on the other hand, Italy has no national policy and Regions still have a hard time integrating them in already existing planning tools. In this perspective, Italian experimentations on GI construction appear to be a simple and sporadic add-on of urban and regional plans

Experimenting Push-Pull Defragmentation in Flexible Optical Networks with Direct Detection

In flexi-grid optical networks, effective defragmentation (i.e., re-optimization) solutions are required to efficiently exploit network spectrum resources. However, current defragmentation solutions can only be implemented thanks to the presence of additional resources, such as spare extensive transponders. In this study, focusing on optically-amplified direct-detection systems, we experimentally demonstrate the feasibility of a novel defragmentation technique, called push-pull, based on dynamic lightpath frequency retuning upon proper reconfiguration of allocated spectrum resources. The technique does not require additional transponders. All the relevant technological limitations that may affect the push-pull applicability are discussed. A simple yet effective close-form expression is also proposed and experimentally validated to assess the maximum retuning range in a single push-pull operation, such that the quality of transmission during defragmentation is safely guaranteed. The technique is then successfully demonstrated in a flexi-grid network testbed. In particular the reoptimization of one lightpath is safely completed in few seconds (mainly due just to node configuration latencies) without experiencing any traffic disruption

Environmental and territorial modelling for planning and design

Between 5th and 8th September 2018 the tenth edition of the INPUT conference took place in Viterbo, guests of the beautiful setting of the University of Tuscia and its DAFNE Department. INPUT is managed by an informal group of Italian academic researchers working in many fields related to the exploitation of informatics in planning. This Tenth Edition pursed multiple objectives with a holistic, boundary-less character, to face the complexity of today socio-ecological systems following a systemic approach aimed to problem solving. In particular, the Conference will aim to present the state of art of modeling approaches employed in urban and territorial planning in national and international contexts. Moreover, the conference has hosted a Geodesign workshop, by Carl Steinitz (Harvard Graduate School of Design) and Hrishi Ballal (on skype), Tess Canfield, Michele Campagna. Finally, on the last day of the conference, took place the QGIS hackfest, in which over 20 free software developers from all over Italy discussed the latest news and updates from the QGIS network. The acronym INPUT was born as INformatics for Urban and Regional Planning. In the transition to graphics, unintentionally, the first term was transformed into “Innovation”, with a fine example of serendipity, in which a small mistake turns into something new and intriguing. The opportunity is taken to propose to the organizers and the scientific committee of the next appointment to formalize this change of the acronym. This 10th edition was focused on Environmental and Territorial Modeling for planning and design. It has been considered a fundamental theme, especially in relation to the issue of environmental sustainability, which requires a rigorous and in-depth analysis of processes, a theme which can be satisfied by the territorial information systems and, above all, by modeling simulation of processes. In this topic, models are useful with the managerial approach, to highlight the many aspects of complex city and landscape systems. In consequence, their use must be deeply critical, not for rigid forecasts, but as an aid to the management decisions of complex systems

A Model For Improving Ethics In Construction Materials And Products Supply Chain Using Blockchain

There are countless materials and products that make up a building, including cladding, glazing, roofing, floors, ceilings, systems, etc., and the hidden and fragmented structure of the supply chain makes it highly vulnerable to several forms of ethical breaches at different tiers. Consumers also are increasingly concerned about where the products they are buying come from, highlighting important areas of concern that include the ethical, environmental, and social issues. Whereas current research identifies digitalization as a key part of providing transparency and increasing fairness in supply chains, and blockchain technology is lauded as having the potential to deliver this. However, while there has been a growing emphasis on ethics in construction in recent years, and an increase in studies around blockchain, there remains a paucity of studies related to how blockchain may help to improve the environmental and social dimensions of ethics in construction supply chains. A gap that this study fills through a holistic triple bottom line (TBL) approach. To achieve this, the study aims to develop and validate a model for improving ethics in construction materials and products supply chains (CMPSC) following the TBL construct using blockchain technology. The study also explores the current state of ethics in the CMPSC and the implementations of blockchain for ethics and applies the learnings to develop a conceptual model to improve environmental, social and business ethics in the CMPSC using blockchain. The model was then refined and validated via a dual-phase validation protocol consisting of expert interviews and focus group discussions. A total of 30 participants participated in this study, this comprised of 16 construction industry supply chain professionals, 10 professionals in the ethics/ sustainability in construction and 4 blockchain technology experts. NVivo 12 was utilised to thematically analyse both the interviews and the focus group data. This approach was utilised to investigate the data from both a data-driven perspective (a perspective based on coding in an inductive way); and from the research question perspective (to check if the data is consistent with the research questions and if it provides sufficient information). The 30 interviews resulted in 4 high-level themes, 15 mid-level themes and 28 low-level themes, with the total number of codes within the themes being 721. The analysis of the focus group data resulted in 3 high-level themes and 10 mid-level themes, bringing the total number of codes within all themes to 74. Results from this study revealed that the effectiveness of current ethical measures in the CMPSC has been limited due to weak implementation and compliance, the inability of the government to play its role, and the outright denial of unethical practises within supply chains. Results also show that even though greater emphasis is placed on the business component of ethics while the environmental or social component may only receive as much attention if it can be monetised or if it is demanded; nonetheless, the current state of ethics in the CMPSC remains weak across the three dimensions examined. Further results show that while blockchain may help improve ethics in the CMPSC, in addition to the transparency and digitization that technology provides, the need for education and the upholding of personal ethical values by supply chain players are key to the success of both current and new ethical supply chain initiatives. Individuals must first be made ethically aware in order to act ethically; only then may the implementation of a technological tool prosper. The main contribution of this study to knowledge is the development of a model for improving ethics in the CMPSC within the TBL construct through blockchain technology. The model developed in this study provides practical clarity on how blockchain may be implemented within fragmented supply chains and a significant understanding of a socio-technical approach to addressing the issue of ethics within construction supply chains. It also has a vital role in helping the intended users and actors improve their knowledge of the technology and how blockchain can help to improve ethics in the CMPSC and also understand their roles and responsibilities on the network, thereby providing a framework and prerequisite guidance for the Blockchain-as-a-Service (BaaS) providers in the development of the computer model (blockchain network). The findings of this thesis demonstrate new insights and contribute to the existing body of knowledge by further advancing the discussion on the role of the blockchain in the construction industry