The connected building [Internet connected building control networks]

Commercial buildings and public venues are often wired up with 20 or more separate networks, responsible for such diverse functions as heating, lighting, ventilation, air conditioning, energy monitoring, fire alarms, and CCTV. Such building control systems have done a decent job for decades. But they are based on proprietary solutions, each with their own local wiring, software and control panels. This article examines the use of a single Internet protocol (IP) based network to carry voice, data, video and wireless information for building control. It details the use of the extensible markup language (XML) that has been developed for data transmission with Internet technologies such as TCP/IP and HTTP. It also describes building control using Web services, often described as middleware or the software 'glue' that sticks systems together. It concludes by presenting several practical installations using this technology.     

Toward the service-rich era [optical access networks]

In order to remain viable the common carriers to develop “optical access network” based on FTTH as soon as possible. Many problems must be overcome in moving from the “metallic” world to the “optical” world, but if carriers hesitate and fail to make this move then they will be in a hopeless situation in the 21st century. This article discusses concepts for realizing optical access networks that are competitive with other media systems and for introducing them to the telephone world, to provide various attractive services to their customers and so gain their continued support     

Power-aware virtual optical network provisioning in flexible bandwidth optical networks [Invited]

Considering the virtual network infrastructure as a service, optical network virtualization can facilitate the physical infrastructure sharing among different clients and applications that require optical network resources. Obviously, mapping multiple virtual network infrastructures onto the same physical network infrastructure is one of the greatest challenges related to optical network virtualization in flexible bandwidth optical networks. In order to efficiently address the virtual optical network (VON) provisioning problem, we can first obtain the virtual links’ order and the virtual nodes’ order based on their characteristics, such as the bandwidth requirement on virtual links and computing resources on virtual nodes. We then preconfigure the primary and backup paths for all node-pairs in the physical optical network, and the auxiliary graph is constructed by preconfiguring primary and backup paths. Two VON mapping approaches that include the power-aware virtual-links mapping (PVLM) approach and the power-aware virtual-nodes mapping (PVNM) approach are developed to reduce power consumption for a given set of VONs in flexible bandwidth optical networks with the distributed data centers. Simulation results show that our proposed PVLM approach can greatly reduce power consumption and save spectrum resources compared to the PVNM approach for the single-line rate and the mixed-line rate in flexible bandwidth optical networks with the distributed data centers.     

Free-space-optical mobile ad hoc networks: Auto-configurable building blocks

Existence of line of sight (LOS) and alignment between the communicating antennas is one of the key requirements for free-space-optical (FSO) communication. To ensure uninterrupted data flow, auto-aligning transmitter and receiver modules are necessary. We propose a new FSO node design that uses spherical surfaces covered with transmitter and receiver modules for maintaining optical links even when nodes are in relative motion. The spherical FSO node provides angular diversity in 3-dimensions, and hence provides an LOS at any orientation as long as there are no obstacles in between the communicating nodes. For proof-of-concept, we designed and tested an auto-configurable circuit, integrated with light sources and detectors placed on spherical surfaces. We demonstrated communication between a stationary and a mobile node using these initial prototypes of such FSO structures. We also performed the necessary theoretical analysis to demonstrate scalability of our FSO node designs to longer distances as well as feasibility of denser packaging of transceivers on such nodes.

Alkylated indolo[3,2,1-jk]carbazoles as new building blocks for solution processable organic electronics

A facile strategy for the introduction of tert-butyl and hexyl chains to the indolo[3,2,1-jk]carbazole scaffold is presented. With these building blocks six materials based on three different 4,4′-bis(N-carbazolyl)-1,1-biphenyl derivatives with varying degree of planarization were prepared. Characterization of the materials showed that the alkyl chains have only minor effects on the photophysical properties of the compounds. In contrast, thermal robustness towards decomposition and electrochemical stability are increased by the introduced alkyl chains. Detailed investigation of the solubility in five different solvents revealed that the incorporation of the alkyl chains increases the solubility significantly. The increased solubility of the materials allowed the application as host materials in red, green and sky-blue solution processed phosphorescent organic light emitting diodes. Hence, this work presents the first solution processed light emitting devices based on the indolo[3,2,1-jk]carbazole scaffold.     

Sip-empowered optical networks for future it services and applications - [Topics in optical communications]

This article presents a novel applicationaware network architecture for evolving and emerging IT services and applications. It proposes to enrich an optical burst switching network with a session control layer that can close the gap between application requests and network control. The session control layer is implemented using the Session Initiation Protocol, giving birth to what is called a SIP-OBS architecture. The article discusses the important added value of this architecture, and shows that it may support a number of end-to-end resource discovery and reservation strategies (for both network and non-network resources). Finally, it presents a testbed implementation where this approach was experimentally validated.     

Toward efficient failure management for reliable transparent optical networks - [Topics in optical communications]

Security and reliability issues are of utmost importance in transparent optical networks due to the extremely large fiber throughput. Fast and successful reaction and restoration mechanisms performed by failure management can prevent loss of large amounts of critical data, which can cause severe service disruption. In this article we discuss failure management issues in TONs, the mechanisms involved, and optical monitoring techniques. Furthermore, we propose applying structural properties of self-organizing systems to create a "small world" hybrid supervisory plane that can enable faster system-wide communication. We also investigate the possibility of a scale-free structure aimed at improving robustness in the network and propose various topology generation algorithms.     

Broadband networks

The Internet's phenomenal growth has created the potential for a ubiquitously connected society. This potential has been slow in coming, however, in part because the majority of today's home users connect to the Internet over slow analog telephone lines. Slow modems and congestion at popular Web sites have further contributed to the “World Wide Wait”. Broadband access (connections at data rates of 250 kbps or more) has long promised a solution, but until recently, technology has been unable to deliver these higher speeds at a reasonable cost. Despite this and other problems, affordable broadband access is just around the corner. What this means for users is a change that will profoundly affect Web access and the existing communication (telephone) and media (TV and radio) industries. The main drivers for narrowband's transition to broadband are new applications that will soon be available. In addition, a slew of new Internet access devices and supporting products will become available in the next few years     

下一代光数据网络的新模型

过去的十年里，光网络技术的两项突破已经成为了满足业务提供商对容量的日益增长的需求的关键因素。第一项是DWDM，它可以将一根光纤分解为多个通道从而提高了现有光纤的可用带宽。第二项是通过使用像波长路由器和交叉连接系统这样的设备实现了带宽的智能化管理，这些设备能够支持具有智能配置和恢复功能的日益动态化的网络。那么下一步是什么呢？目前摆在人们面前的主要有两个挑战。其一是在需求以超乎想象的速度增长的情况下，对以数据为核心的网络不断地进行扩充，从用户接入点到城域网乃至整个长途核心网。另一个挑战是有效地创建并管…     

Grade-of-service-based routing in optical networks [Quality-of-Service-Based Routing Algorithms for Heterogeneous Networks]

Optical networks serve an increasing number of services, each having different requirements. This necessitates the evolution towards routing algorithms that cover all aspects of quality. This article presents a tutorial overview and comparison of grade-of-service-based routing strategies, with emphasis on mechanisms that provide differentiated call-blocking probability for different classes of lightpath requests     

Multipath restoration and bitrate squeezing in SDN-based elastic optical networks [Invited]

Sliceable bandwidth-variable transponders (SBVTs) enable the adaptation of transmission parameters according to traffic requirements and network constraints. In this study, SBVTs capabilities are evaluated in the context of restoration. In particular, multipath recovery and bitrate squeezing are applied to maximize the amount of restored bitrate, also exploiting limited portions of spectrum resources along multiple routes. An integer linear programming model and heuristic strategy are proposed. A software defined network (SDN) architecture is then introduced to adequately support the SBVT configuration. The SDN architecture is applied to experimentally assess that the overall re-configuration time upon failure detection is included within two seconds, largely dominated by the proprietary control of bandwidth-variable optical cross-connects. Finally, extensive simulation results show the relevant restoration capabilities achieved by the proposed multipath recovery and bitrate squeezing scheme.     

Translucent optical networks: the way forward [Topics in Optical Communications]

The transmission reach of signals in optical transmission systems is limited. To go beyond these transparent reach limits, signal regeneration is necessary to re-amplify, reshape, and retime the optical signals. Translucent optical networks are a type of optical transport network specifically devised to address such a concern by allowing for sparse but strategic signal regeneration in the network. Translucent optical networks seek a graceful balance between network design cost and service provisioning performance, and can achieve performance comparable to that of an all-electronic switching network, but requiring far fewer signal regenerators. Despite massive progress, there are many outstanding issues regarding the implementation of translucent networks planning and operation. This article reviews a range of translucent optical networks and discusses various research issues, particularly involving network planning, lightpath routing and wavelength assignment, and network survivability. We also suggest other potential research topics such as traffic grooming, fault detection, and multicasting for translucent networks     

A dynamic impairment-aware networking solution for transparent mesh optical networks - [Topics in optical communications]

Core networks of the future will have a translucent and eventually transparent optical structure. Ultra-high-speed end-to-end connectivity with high quality of service and high reliability will be realized through the exploitation of optimized protocols and lightpath routing algorithms. These algorithms will complement a flexible control and management plane integrated in the proposed solution. Physical layer impairments and optical performance are monitored and incorporated in impairment-aware lightpath routing algorithms. These algorithms will be integrated into a novel dynamic network planning tool that will consider dynamic traffic characteristics, a reconfigurable optical layer, and varying physical impairment and component characteristics. The network planning tool along with extended control planes will make it possible to realize the vision of optical transparency. This article presents a novel framework that addresses dynamic cross-layer network planning and optimization while considering the development of a future transport network infrastructure.