一种IP分组重组的集群并行计算的方法

基于N元非合作模型的路由切割调度算法的基础,利用集群来解决大规模的IP分组重组问题是一个可行的办法。论文设计实现了IP分组重组（又称网络地址转换NAT,Network Address Transfer）的集群并行计算方法。使用普通PC构建了基于MPI用于IP分组重组计算的SMP集群,研究了在典型的校园网环境下的较大规模的IP分组重组环境并讨论了集群内部计算节点上的两种负载平衡方法。     

Seamless User-Level Handoff in Ubiquitous Multimedia Service Delivery

Advancing mobile computing technologies are enabling ubiquitous personal computing environment. In this paper, we focus on an important problem in such environment: user mobility. In the case of user mobility, a user is free to access his/her personalized service at anytime, anywhere, through any possible mobile/fixed devices. Providing mobility support in this scenario poses a series of challenges. The most essential problem is to preserve the user's access to the same service despite changes of the accessing host or service provider. Existing system-level mobility solutions are insufficient to address this issue since it is not aware of the application semantics. On the other hand, making each application to be mobility-aware will greatly increase the development overhead. We argue that the middleware layer is the best place to address this problem. On one hand, it is aware of application semantics. On the other hand, by building application-neutral mobility functions in the middleware layer, we eliminate the need to make each application mobility-aware. In this paper, we design a middleware framework to support user mobility in the ubiquitous computing environment. Its major mobility functions include user-level handoff management and service instantiation across heterogeneous computing platforms. We validate the major mobility functions using our prototype middleware system, and test them on two multimedia applications (Mobile Video Player and Mobile Audio Player). To maximally approximate the real-world user-mobility scenario, we have conducted experiments on a variety of computing platforms and communication paradigms, ranging from T1-connected high-end PC to handheld devices with wireless networks. The results show that our middleware framework is able to provide efficient user mobility support in the heterogeneous computing environment.     

基于Web的嵌入式设备监控模型的设计与实现

研究并实现了一种基于Web技术的嵌入式没备监控模型,使管理者可以通过Internet利用Web浏览器完成对现场设备的远程访问、监控和维护等操作,实现了异构设备之间的跨平台互访。对TCP／IP协议进行约简,实现了一个thin TCP／IP协议栈,为嵌入式设备提供了网络接口,实现了与Internet的无缝连接。嵌入式没备网关将TCP／IP协议与嵌入式设备监控协议之间的格式进行转换,实现了远程用户对现场设备的透明访问,具有智能化和远程管理的特点。通过对该模型性能的测试,结果表明基于Web的远程监控方式可以满足监控任务的需要,而且能有效降低监控运行维护成本、提高运行维护效率,具有实际应用价值。     

Issues in emerging 4G wireless networks

Researchers and vendors are expressing a growing interest in 4G wireless networks that support global roaming across multiple wireless and mobile networks. With this feature, users will have access to different services, increased coverage, the convenience of a single device, one bill with a reduced total access cost, and more reliable wireless access even with the failure or loss of one or more networks. 4G networks will also feature IP interoperability for seamless mobile Internet access and bit rates of 50 Mbps or more. Because deployment of 4G wireless technology is not expected until 2006 or even later, developers will hopefully have time to resolve issues involving multiple heterogeneous networks     

Scalable multimedia delivery with QoS management in pervasive computing environment

People are increasingly demanding rich-media and bundled services. However, the diverse terminals, heterogeneous networks as well as various user requirements constrain the multimedia access to low quality in the pervasive computing environment. In order to enable rich-media delivery across a wide range of devices and networks, multimedia adaptation with scalable QoS management is an important issue. Our research introduces a Scalable Multimedia Delivery (SMD) framework with QoS management. This framework utilizes the CAM4Home metadata model to aggregate multimodal rich media services into a bundle. MPEG-21 metadata is integrated into the CAM4Home model to enforce interoperable QoS management. The issues in supporting QoS are addressed on both fidelity and modality. We further develop the SMD system in IP Multimedia Subsystem (IMS) architecture, where multimedia adaptation is implemented through application-level QoS negotiation.     

Network Resource Awareness and Control in Mobile Applications

As mobile devices become increasingly capable of simultaneously using various kinds of wireless and fixed networks, developers must match mobile application needs to network resource dynamics. The authors' network resource model and network abstraction layer (NAL) software offer an extensible network resource abstraction to applications running on mobile devices. The NAL service can be used in conjunction with well-known APIs, such as the Socket API, which provide access to these resources; it also accommodates support for mobility-management facilities, such as mobile IP, if available     

Wired-wireless integration

Within a few years, most wireless devices will interconnect across networks to allow information access from anywhere, anytime. This evolution motivates developers to migrate technologies originally developed for PCs to wireless devices. Supporting this effort, however, requires new software -particularly middleware -to power small devices that connect over slow, sometimes unreliable networks. How well can today's major middleware platforms support wireless access to business applications?.     

Leveraging deployment models on low-resource devices for cloud services in community networks

Community networks are crowd-sourced IP networks that evolved into regional-scale computing platforms. This has led to adapting the cloud computing model for services that can operate and use computing resources inside a community network. The network and computing infrastructure is contributed by individuals, companies, organizations and maintained by its members. Community cloud devices are often low-capacity computing devices, such as home gateways or cabinet servers, with limited capabilities. These devices are used to install and operate specific personal or community services, but can be turned into multi-purpose execution environments applying machine or operating system (container) virtualization. However that requires addressing the problems of resource sharing in low-capacity devices, related to predictable performance and isolation. Our comparative analysis with the current infrastructure in community networks gives evidence about how devices can concurrently run multiple services, the trade offs between the number and resource requirements of services and the degradation of quality that services may suffer.     

Autoconfiguration for IP networking: enabling local communication

IP hosts and network infrastructure have historically been difficult to configure, but emerging networking protocols promise to enable hosts to establish IP networks without prior configuration or network services. Even very simple devices with few computing resources will be able to communicate via standard protocols wherever they are attached. Current IETF (Internet Engineering Task Force) standardization efforts, such as those in the Zeroconf Working Group, aim to make this form of networking simple and inexpensive. In this tutorial, I examine the background, current status and future prospects for zero-configuration networking     

Enabling Delivery of Mobile Services Over Heterogeneous Converged Infrastructures

Traditionally, end customers have been offered different categories of communication, data and media services (e.g., fixed/mobile voice, fixed/mobile data, broadcasting) through vertically separated, rigidly integrated infrastructures. Major advances in a variety of technological fields, mainly in the area of mobile computing and networking, have created prospects for a fully converged environment, where ubiquitous access to an abundance of value-added services will be offered over a single, as perceived by the users, highly reconfigurable system. This vision can be enabled by the seamless plugging of diverse access networks to a high-speed IP backbone; however the path to its realization poses a variety of additional challenges. The required support of complicated business models and service delivery over highly diverse contexts introduces significant complexity to service management and provision. The present contribution presents object-oriented mediating service management platforms as a catalyst for making these demanding tasks feasible, identifies their desired functionality and provides an overview of such a distributed framework that we have designed and prototyped. Furthermore, we demonstrate that the latter is able to be a critical enabler of flexible, adaptable service provision over future heterogeneous networks, while supporting advanced business paradigms.     

基于IMS的E2E QOS控制机制

3GPP提出的IMS用于提供各种实时多媒体业务,未来的实时多媒体服务将以视频、音频以及视频、音频的混合为主,对于实时性和延迟的要求很高,需要E2E的QOS的支持。文章分析了现有的IMS的QOS机制的实现以及存在的不足,提出了一种新的基于策略的E2EQOS机制。新的机制主要实现了IMS中的各个层次间的相互协作、SIP协议的扩展和PDF功能的改进,实现了对多媒体业务实时性的提高并且缩短了延迟。     

Service level agreements (SLAs) parameter negotiation between heterogeneous 4G wireless network operators

We are currently witnessing a growing interest of network operators to migrate their existing 2G/3G networks to 4G technologies such as long-term evolution (LTE) to enhance the user experience and service opportunities in terms of providing multi-megabit bandwidth, more efficient use of radio networks, latency reduction, and improved mobility. Along with this, there is a strong deployment of packet data networks such as those based on IEEE 802.11 and 802.16 standards. Mobile devices are having increased capabilities to access many of these wireless networks types at the same time. Reinforcing quality of service (QoS) in 4G wireless networks will be a major challenge because of varying bit rates, channel characteristics, bandwidth allocation and global roaming support among heterogeneous wireless networks. As a mobile user moves across access networks, to the issue of mapping resource reservations between different networks to maintain QoS behavior becomes crucial. To support global roaming and interoperability across heterogeneous wireless networks, it is important for wireless network operators to negotiate service level agreement (SLA) contracts relevant to the QoS requirements. Wireless IP traffic modeling (in terms of providing assured QoS) is still immature because the majority of the existing work is merely based on the characterization of wireless IP traffic without investigating the behavior of queueing systems for such traffic. To overcome such limitations, we investigate SLA parameter negotiation among heterogeneous wireless network operators by focusing on traffic engineering and QoS together for 4G wireless networks. We present a novel mechanism that achieves service continuity through SLA parameter negotiation by using a translation matrix, which maps QoS parameters between different access networks. The SLA matrix composition is modeled analytically based on the G/M/1 queueing system. We evaluate the model using two different scheduling schemes and we derive closed form expressions for different QoS parameters for performance metrics such as packet delay and packet loss rate. We also develop a discrete event simulator and conduct a series of simulation experiments in order to understand the QoS behavior of corresponding traffic classes.     

Delay analysis of downlink IP traffic on UMTS mobile networks

Since wireless networks which can carry high bit rates have become ubiquitous, mobile computing is no longer just spoken about. Mobile computing always implies access through a wireless network to an IP network such as the Internet. In order to understand the performance of such links, we propose an analytic model for the down link delay of IP traffic between the Mobile Gateway Server and the End User in a UMTS mobile network. Traffic arriving at the Gateway Server is considered to be bursty in nature and we use a Batch Markovian Arrival Process (BMAP) to model this arrival process. We model the wireless link itself as a modified multi-state Gilbert–Elliot Markov model which takes into account the number of interfering users and whether the channel experiences Ricean fading or not for what we consider a typical indoor, IP-centric environment. We also account in both the analytical model and the simulation for the Forward Error Correction provided by Turbo coding in UMTS to establish realistic packet retransmission rates. Finally we calibrate and verify the correctness of the model with a discrete event simulator.     

Design and energy-efficient resource management of virtualized networked Fog architectures for the real-time support of IoT applications

With the incoming 5G access networks, it is forecasted that Fog computing (FC) and Internet of Things (IoT) will converge onto the Fog-of-IoT paradigm. Since the FC paradigm spreads, by design, networking and computing resources over the wireless access network, it would enable the support of computing-intensive and delay-sensitive streaming applications under the energy-limited wireless IoT realm. Motivated by this consideration, the goal of this paper is threefold. First, it provides a motivating study the main “killer” application areas envisioned for the considered Fog-of-IoT paradigm. Second, it presents the design of a CoNtainer-based virtualized networked computing architecture. The proposed architecture operates at the Middleware layer and exploits the native capability of the Container Engines, so as to allow the dynamic real-time scaling of the available computing-plus-networking virtualized resources. Third, the paper presents a low-complexity penalty-aware bin packing-type heuristic for the dynamic management of the resulting virtualized computing-plus-networking resources. The proposed heuristic pursues the joint minimization of the networking-plus-computing energy by adaptively scaling up/down the processing speeds of the virtual processors and transport throughputs of the instantiated TCP/IP virtual connections, while guaranteeing hard (i.e., deterministic) upper bounds on the per-task computing-plus-networking delays. Finally, the actual energy performance-versus-implementation complexity trade-off of the proposed resource manager is numerically tested under both wireless static and mobile Fog-of-IoT scenarios and comparisons against the corresponding performances of some state-of-the-art benchmark resource managers and device-to-device edge computing platforms are also carried out.     

iSCSI协议的跨平台实现

SCSI协议是主要的I/O设备通信协议,iSCSI将SCSI协议映射到TCP／IP协议,用于访问IP网络上的SCSI存储设备。本文讨论如何在Windows2000和Linux之间跨平台实现iSCSI协议。     

A newly emerging customer premises paradigm for delivery of network-based services

Low-speed home networks in some form are used for lighting, appliance control and security systems in over 20% of U.S. households. The increasing penetration of personal computers (PCs) is leading to early deployment of twisted-pair Ethernet networks by information industry employees and early technology adopters. Digital video has matured to the point where the power of the MPEG compression algorithm is bearing fruit in new consumer electronics. The “jury is still out” on ultimate convergence of the entertainment center and the PC. However, it has definitely progressed with the advent of television Web appliances, and with the addition of video attributes being pulled down from Web sites and played on the PC. Rather than think of convergence in the context of a single-user device with full capability, increasing use of advanced digital networks in the home is the more likely evolution, with devices optimized for their particular task easily connecting to a whole-house network through attractive wall plates, by wireless, or through their commercial a.c. power cords. Several industries are formulating such concepts, examining advanced broadband digital networks with “plug-and-play” capabilities. For network service providers competing in an increasingly unregulated environment, success of service delivery will come to depend on a well-thought-out strategy for service termination. The old paradigm of “customer premises equipment” which was relatively well defined, specified and controlled by the network operator will give way to home networks which are extremely sophisticated in their own right. Service providers will be forced to think in terms of delivering services into this local environment, with an interface which is more driven by the customer's local deployment decisions, somewhat analogous to the business environment today in which carriers provide trunks and private lines to PBXs and gateways. This paper will examine the trends in home networking, and propose architectures which service providers can use to deliver services to, and across, home networks, to end-user devices. We will discuss recent industry activity focused on the concept of a residential gateway (RG), an electronic device which mediates between different service-provider access networks and different devices and networks within the home. We will discuss how the RG can facilitate intelligent testing capabilities to reduce maintenance costs, and intelligent provisioning which can support flexible service capabilities.     

Object Organization on a Single Broadcast Channel in the Mobile Computing Environment

Advances in computation and communication technologies allow users to access computer networks, using portable computing devices via a wireless connection, while mobile. Furthermore, multidatabases offer practical means of managing information sharing from multiple preexisting heterogeneous databases. By superimposing the mobile computing environment onto the multidatabase system, a new computing environment is attained.In this work, we concentrate on the effects of the mobile-computing environment on query processing in multidatabases. We show how broadcasting, as a possible solution, would respond to current challenges such as bandwidth and storage limitations. Organizing data objects along a single-dimension broadcast channel should follow the semantic links assumed within the multiple-dimension objects' structure. Learning from our past experiences in objects organization on conventional storage mediums (disks), we propose schemes for organizing objects along a single broadcast air channel. The proposed schemes are simulated and analyzed.     

Ambient multimodality: towards advancing computer accessibility and assisted living

The aim of this paper is to point out the benefits that can be derived from research advances while implementing concepts such as ambient intelligence and ubiquitous/pervasive computing for promoting universal access in the information society, that is, for contributing to enable everybody, especially people with physical disabilities, to have easy access to all computing resources and information services that the upcoming worldwide information society will soon make available to the general public as well as to expert users. Following definitions of basic concepts relating to multimodal interaction, the significant contribution of multimodality to developing universal access is briefly discussed. Then, a short state of the art in ambient intelligence research is presented, including references to some major research projects either in progress or recently completed. The last section is devoted to bringing out the potential contribution of advances in ambient intelligence research and technology to the improvement of computer access for physically disabled people, hence, to the implementation of universal access. This claim is mainly supported by the following observations: (1) most projects are aiming at implementing ambient intelligence focus research efforts on the design of new interaction modalities and flexible/adaptive multimodal user interfaces; outcomes of these projects may contribute to improving computer access for users with physical disabilities; (2) such projects target applications meant to support users in a wide range of daily activities which will have to be performed simultaneously with the related supporting computing tasks; therefore, users will be placed in situational contexts where they will be confronted with similar difficulties to those encountered by physically disabled users, since they will have to share out their perceptual and motor capabilities between one or several daily activities and the computing tasks meant to support them; (3) ambient intelligence applications being intended for the general public, a wide range of interaction devices supporting a great variety of input and output modalities will be available, making it possible to provide physically disabled users with appropriate human–computer interaction means tailored to their individual needs at a reasonable expense.