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Evidence is drawn from the 411 alumni of the MPhil in Engineering for Sustainable Development professional practice programme at University of Cambridge to examine whether the sustainability dimension of their education has i) provided them with a mix of skills which they use on a regular basis, ii) equipped them to be more effective in the roles they fulfil, and iii) given them confidence to act as agents of change in developing sustainability thinking and seeking out solutions that satisfy multiple constraints within their organisations. The relevance of the content of this sustainability programme is assessed and frustrations experienced by graduate sustainable engineers and the barriers to change are discussed.

The new paradigm of web usage has motivated in recent years a series of proposals to update the standard Internet protocols related to web traffic. Some of these proposals provided suggestions to upgrade or even completely replace current Hypertext Transport Protocol (HTTP). Others, instead, focused on new TCP transport mechanisms (larger initial window, fast connection open, congestion window validation, tail loss probe, etc.) that are meant to accelerate the completion time of short data transfers. Web technologies are penetrating areas of computer-science before only the prerogative of dedicated computer systems, such as Cloud computing and Service- oriented applications. Web technologies are becoming increasingly prevalent as the delivery model for a wide range of applications, using methods such as Service- oriented architecture (SOA) or software as a service (SaaS). These methods implement the concept of ASP (application service provider) and on-demand computing software delivery: the provider hosts commercially available software and delivers copies of it over the Web, customising the software according to a client's needs. These changes are driving significant alterations in the traffic patterns generated by applications, but the impact of such changes are still uncertain. These changes are also set to change the requirements placed on a network - with an increasing emphasis on minimising web page download time, and an increasing need to consider on-off interactivity. The motivation for transport changes is a growing availability of high speed xDSL/cable access. These high-speed services differ from most wireless and satellite systems in key ways. Current wireless/satellite systems typically employ dynamic capacity schemes with protocol accelerators and access methods that have been tuned for the existing web traffic. The traffic patterns and protocol behaviour of new web protocols is very different. It is therefore important to assess the implications on the design and operation of satellite systems as the new web is increasingly used. This is the focus of this document. The document (TN3.1) reviews the current state-of-the-art of web technologies and surveys the recent proposals, such as SDPY. This document reviews the problems these protocols are trying to solve, and notes the way they try to solve them. In particular, the HTTP/2.0 standard is a new Internet application-layer that defines a new semantic. This is presently a joint effort between the World Wide Web Consortium (W3C) and the Internet Engineering Task Force (IETF). The starting point for the standard inherits ideas from SPDY, an open standard developed by Google and currently available in a wide range of web browsers, including Chromium, Mozilla Firefox and Opera. HTTP/2.0 promises to reduce web page load latency and improve web security using a combination of techniques, including compression, and multiplexing.

This project explores the potential implications of introducing the HTTP/2.0 web technology on the design and operation of satellite networks. It has been recognised that as network bandwidth increases, the greater obstacle to the performance of web technology is latency rather than scarcity of capacity. HTTP/2.0 [RD-8] is a new protocol being design by the Internet Engineering Task Force (IETF) and World Wide Web Consortium (W3C) to address the limitations and lack of flexibility of the currently widely deployed HTTP/1.1 [RD-4]. The origin of the emerging HTTP/2.0 standard may be traced back to a GoogleTM suite of protocols, called SPDY. Proposed modifications to HTTP/1.1 include suppression of unnecessary Round Trip Time (RTT) delays to request and deliver web objects, multiplexing of web streams into a single connection, removal of the head of line (HoL) blocking, more compact encoding of HTTP headers, server initiated transmissions (Server Push), a new security model, and an extensible design. In parallel, a number of initiatives from well-known IT actors (GoogleTM, AppleTM etc) have proposed new transport methods, such as QUIC [RD-7] or Minion [RD-23], to enhance performance for web traffic. It is expected that the final HTTP/2.0 specification will replace HTTP/1.1 in every scenario HTTP/1.1 is currently used. The goal of Task3 of CoO3 Satnex-III was to understand the trajectory of the emerging web technologies and to evaluate the expected impact on satellite networking. Different aspects have been analysed by Satnex partners using both real satellite testbeds and emulation. This analysis included evaluation of SPDY performance over satellite and experiments to understand the expected interaction with PEPs (including scenarios with a SPDY proxy at a satellite gateway), the impact of security, and the effect of satellite capacity allocation mechanisms. The analysis also considered the impact of application protocols and the delay induced by end- system networks, such as a satellite-connected WiFi network. In general, experimental results show that HTTP/2.0 benefits the performance of web browsing via satellite by reducing latency and significantly lowering the overhead for several types of web pages. In particular, multiplexing a sequence of small web objects on a webpage onto a single connection enables siginicant gain and effectively reduces the HTTP overhead per object and per connection. The Server Push feature of HTTP/2.0, adds the ability for the server to send objects without explicit request, and was found particularly useful to reduce the download time. However these gains come at a cost, since they impact the design and operation of satellite networks. We also observed places where the tested implementations did not perform optimally, and were performance over satellite-connected WiFi networks was less than would be expected with HTTP/1.1. However, at the time of writing, the work on HTTP/2.0 is not complete and many mechanisms remain to be finalised. Modifications and adjustments are expected in future. Moreover, the current software support for HTTP/2.0 is not yet completely stable, and is expected to continue to evolve long after initial deployment. Satellite networking equipment will need to be updated to support HTTP/2.0. In particular, designs must re-consider the integration of PEPs withHTTP/2.0 and the updated security model, based on Transport Layer Security (TLS). TLS encryption prevents visibility of HTTP headers at satellite equipment, preventing use of current 23089/10/NL/CLP Executive and Summary Report 15/40 III CoO3 - Task 3 - Future Web Technologies and Protocols over Broadband GEO Satellite Networks HTTP acceleration PEPs. Our tests suggest that this problem may be mitigated by HTTP/2.0 itself, because some of the functions implemented in application-layer PEPs (compression, pipeling/multiplexing, push) are already present in HTTP/2.0. HTTP/2.0 is still in a development phase and it is important for the satellite community to watch carefully its progress and understand the implications this will place on the design of the higher layer packet processing. This is especially important because the new model does not introduce a single solution, but more represents a toolkit of techniques that will continue to evolve and will be deployed incrementally over a timescale of months and years ahead. There is also a need to understand the implications on network design/configuration, to ensure that satellite continues to offer high quality service comparable to terrestrial networks, and a need to re-consider the role of PEP in this new architecture. We also urge the satellite networking community to influence development of these standards. As network latency becomes important there is increased focus on low- delay networks, and it is important to ensure that design decisions (maybe unintentional) do not prejudice the performance over long delay paths when the new protocols are deployed.

International audience; Broadband satellite will play an important role to provide universal broadband access for the users. In order to lower the cost, the next-generation satellite systems should support IPv6 and seamlessly integrate with terrestrial networks, including wireless local loops. Based on the studies on the requirements and design constraints, in this paper, a novel network architecture has been proposed as a potential solution to the above problems. The proposed network architecture supports both transparent and regenerative topologies and can seamlessly interworking with WLL. It also integrates QoS, multicast, security, and mobility functions to support a range of transport requirements. How to apply this network architecture to support three different scenarios, namely corporate application scenario, residential application scenario and collective access terminal scenario, are also described.

This is the second part of the tutorial paper following the previous tutorial paper describing enabling technologies in digital video broadcasting (DVB) system. The paper presents the current and future operational scenarios for DVB via satellite (DVB-S) system. Review of the current state-of-the-art technologies consisting of integration of broadband Internet and mobile communications and integration of broadband Internet and DVB are given. The future operational scenarios emphasize the fusion of DVB systems with other technologies in terms of network fusion and terminal fusion. For satellite service scenarios, it also takes into consideration mobility management and standard quality-of-service mechanism issues, such as integrated services and di

The introduction of digital video broadcasting (DVB) satellite systems has become an important tool for future mobile communication and is currently a focus in several research areas such as the integration of DVB satellite systems with different wireless technologies. This tutorial consists of two parts, Enabling technologies and Future service scenarios, which aims to provide an introduction to the current state-of-theart of DVB standards over satellite and its fusion with mobile and Internet technologies. This paper, Enabling technologies, focuses on providing an overview of the different technologies and issues that facilitates better understanding of the current and future operational scenarios, whereas the second paper, Future service scenarios will emphasize future research directions in this research area. In the first part, the paper will initially be focused on the introduction of different DVB satellite systems, i.e. DVB-via satellite (DVB-S), DVB return channel by satellite (DVB-RCS) and second-generation DVB system for broadband satellite services (DVB-S2). This is then followed by a description of the different Internet Protocol (IP) technologies used to support macro- and micro-mobility and the migration strategies from IP version 4 (IPv4) to IP version 6 (IPv6). Finally, the different security mechanisms for the DVB system and end-to-end satellite network are addressed.

This is the second part of the tutorial paper following the previous tutorial paper describing enabling technologies in digital video broadcasting (DVB) system. This part focuses on the current and future operational scenarios for DVB-S system. Scenario based review of current state-of-the-art technologies consisting of integration of broadband Internet and mobile communication and integration of broadband Internet and DVB are given. The future operational scenarios emphasises the fusion of DVB systems with various access technologies, terminal, services and network. It also takes into consideration mobility management (MM) and standard quality of service (QoS) mechanisms issues, such as integrated services (IntServ) and differentiated services (DiffServ). Several research directions for providing seamless services regardless of network, access technology, and terminal in the fusion network are also highlighted in this paper.

The introduction of digital video broadcasting (DVB) satellite systems has become an important tool for future mobile communication and is currently a focus in several research areas such as the integration of DVB satellite systems with different wireless technologies. This tutorial consists of two parts, Enabling Technologies and Future Service Scenarios, which aims to provide an introduction to the current state-of-the art of Digital Video Broadcasting standards over satellite and its fusion with mobile and Internet technologies. This paper, Enabling Technologies, focuses on providing an overview of the different technologies and issues that facilitates better understanding of the current and future operational scenarios, whereas the second paper, Future Service Scenarios will emphasise future research directions in this research area. In the first part, the paper will initially be focused on the introduction of different DVB satellite systems, i.e. DVB-via satellite (DVB-S), DVB return channel by satellite (DVB-RCS) and Second-generation DVB system for broadband satellite services (DVB-S.2). This is then followed by a description of the different internet protocol (IP) technologies used to support macro and micro-mobility and the migration strategies from IP version 4 (Ipv4) to IP version 6 (IPv6). Finally, the different security mechanisms for the DVB system and end-to-end satellite network are addressed.