Toward incremental FIB aggregation with quick selections (FAQS)

Several approaches to mitigating the Forwarding Information Base (FIB) overflow problem were developed and software solutions using FIB aggregation are of particular interest. One of the greatest concerns to deploy these algorithms to real networks is their high running time and heavy computational overhead to handle thousands of FIB updates every second. In this work, we manage to use a single tree traversal to implement faster aggregation and update handling algorithm with much lower memory footprint than other existing work. We utilize 6-year realistic IPv4 and IPv6 routing tables from 2011 to 2016 to evaluate the performance of our algorithm with various metrics. To the best of our knowledge, it is the first time that IPv6 FIB aggregation has been performed. Our new solution is 2.53 and 1.75 times as fast as the-state-of-the-art FIB aggregation algorithm for IPv4 and IPv6 FIBs, respectively, while achieving a near-optimal FIB aggregation ratio

Leveraging Programmable Data Plane For Compressing Forwarding Tables

The Forwarding Information Base (FIB) resides in the data plane of a routing device and is used to forward packets to a next-hop, based on packets\u27 destination IP addresses. The constant growth of a FIB forces network operators to spend more resources on maintaining memory with line-rate Longest Prefix Match (LPM) lookup in a FIB, namely, expensive and energy-hungry Ternary Content-Addressable Memory (TCAM) chips. In this work, we review two different approaches used to mitigate the FIB overflow problem. First, we investigate FIB aggregation, i.e., merging adjacent or overlapping routes with the same next-hop while preserving the forwarding behavior of a FIB. We propose a near-optimal algorithm, FIB Aggregation with Quick Selections (FAQS), that minimizes the FIB churn and speeds BGP update processing by more than twice. In the meantime, FAQS preserves a high compression ratio (at most 73\%). FAQS handles BGP updates incrementally, without the need of re-aggregating the entire FIB table. Second, we investigate FIB (or route) caching, when TCAM holds only a portion of a FIB that carries most of the traffic. We leverage the emerging concept of the programmable data plane to propose a Programmable FIB Caching Architecture (PFCA), that allows cache-victim selection at the line rate and significantly reduces the FIB churn compared to FIB aggregation. PFCA achieves 99.8% cache-hit ratio with only 3.3\% of the FIB placed in a FIB cache. Finally, we extend PFCA\u27s design with a novel approach of integrating incremental FIB aggregation and FIB caching. Such integration needed to overcome cache hiding challenge when a less specific prefix in a cache hides a more specific prefix in a secondary FIB table, which leads to incorrect LPM matching at the cache. In Combined FIB Caching and Aggregation (CFCA), cache-hit ratio is maximized up to 99.94% with only 2.5\% entries of the FIB, while the total number of route changes in TCAM is reduced by more than 40\% compared to low-churn FIB aggregation techniques

London’s Urban Landscape

London’s Urban Landscape is the first major study of a global city to adopt a materialist perspective and stress the significance of place and the built environment to the urban landscape. Edited by Christopher Tilley, the volume is inspired by phenomenological thinking and presents fine-grained ethnographies of the practices of everyday life in London. In doing so, it charts a unique perspective on the city that integrates ethnographies of daily life with an analysis of material culture. The first part of the volume considers the residential sphere of urban life, discussing in detailed case studies ordinary residential streets, housing estates, suburbia and London’s mobile ‘linear village’ of houseboats. The second part analyses the public sphere, including ethnographies of markets, a park, the social rhythms of a taxi rank, and graffiti and street art

London's Urban Landscape: Another Way of Telling

London’s Urban Landscape is the first major study of a global city to adopt a materialist perspective and stress the significance of place and the built environment to the urban landscape. Edited by Christopher Tilley, the volume is inspired by phenomenological thinking and presents fine-grained ethnographies of the practices of everyday life in London. In doing so, it charts a unique perspective on the city that integrates ethnographies of daily life with an analysis of material culture. The first part of the volume considers the residential sphere of urban life, discussing in detailed case studies ordinary residential streets, housing estates, suburbia and London’s mobile ‘linear village’ of houseboats. The second part analyses the public sphere, including ethnographies of markets, a park, the social rhythms of a taxi rank, and graffiti and street art. London’s Urban Landscape returns us to the everyday lives of people and the manner in which they understand their lives. The deeply sensuous character of the embodied experience of the city is invoked in the thick descriptions of entangled relationships between people and places, and the paths of movement between them. What stories do door bells and house facades tell us about contemporary life in a Victorian terrace? How do antiques acquire value and significance in a market? How does living in a concrete megastructure relate to the lives of the people who dwell there? These and a host of other questions are addressed in this fascinating book that will appeal widely to all readers interested in London or contemporary urban life

Examination of existing facilities management approaches to climate change and future directions

It is widely accepted that human activities have contributed to changing the world’s climate and that the pace of this change is ever increasing. Two approaches are being promoted by the international community to address the issue of climate change (1) Mitigation, seeking to reduce the amount of CO2; (2) Adaptation, which seeks to alter the way humankind live and work in response to the changing climate. Whilst facilities managers and their organisations have prioritised mitigation action, there is less evidence to suggest that they are addressing the implications that a changing climate may have on the demands being placed on their organisation’s hard and soft facilities (adaptation). This paper reports findings from a case study and questionnaire survey to ascertain the present approach taken by facilities managers to address mitigation and adaptation, their respective drivers, their view on climate change and their environmental inclination. It concludes that the facilities manager's approach to climate change is derived by a combination of factors; namely a) Organisation approach to climate change b) Legislation and c) the facilities mangers perception of the risks posed by future climate change and of the use of risk assessment methods and climate change projection data. The study concludes that the prevailing measure for addressing climate change impacts is reactive in nature, taking the form of Disaster Recovery and Business Continuity Planning. The practical implication of the work is in the realization that mitigation, being quantifiable and legislative driven, is viewed as a strategic issue and of importance to an organisations Corporate Social Responsibility agenda which can be planned over the longer term (10-20 yrs). Adaptation on the other hand is measured through successful survival, increased resilience and adaptive capacity (absence of quantitative performance target), each of which are viewed as short term operational issues and as such adaptation struggles to find strategic importance. If organisations are to adapt to inevitable climate change then this situation needs to change

Improving the structural design process : a knowledge management approach

Knowledge is crucial for structural design, yet existing methodologies for managing it are neither comprehensive nor do they adequately address the requirements of structural engineers. This knowledge exists in different forms and repositories therefore requiring special consideration as to how it should be managed. Poor management of structural design knowledge can result in many problems such as increased design time, reduced quality and decreased scope for innovation. Knowledge Management (KM) remains largely unexplored within the context of structural design although it is a valuable concept. The research in this thesis was aimed at developing a structured approach to managing structural design knowledge. The research methodology adopted consisted of various methods. Literature on structural design and KM was first reviewed. Case studies involving thirteen organisations were then undertaken to investigate the potential of KM for managing structural design knowledge and to develop a conceptual framework and methodologies for formulating KM strategies and evaluating the impact of KM initiatives. Rapid prototyping (based on MS Visual Basic) was used to encapsulate the methodologies into prototype systems, which were evaluated by industry practitioners. The evaluation established that the systems do proffer many benefits to the construction industry and facilitate the development of a KM strategy for managing the very specialised knowledge of structural design. It is concluded that the process of structural design suffers from several problems where managing the tacit and explicit knowledge involved in the process did not receive adequate attention. The research also concludes that KM has the potential to improve the structural design process and that the framework developed and its associated prototypes help to clarify a KM problem, identify goals for implementing KM, develop a KM strategy and evaluate the strategy. The prototypes also support KM at both the strategic and tactical levels, unlike other existing IT tools, which support KM primarily at the operational level. Recommendations for future research include further improvement to the prototypes, additional evaluation using a wider range of real cases and integrating the two prototypes into one system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Life Sciences Program Tasks and Bibliography

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1995. Additionally, this inaugural edition of the Task Book includes information for FY 1994 programs. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web pag