Showing papers on "Heterogeneous network published in 2000"

Wireless integrated network sensors

Abstract: W ireless integrated network sensors (WINS) provide distributed network and Internet access to sensors, controls, and processors deeply embedded in equipment, facilities, and the environment. The WINS network represents a new monitoring and control capability for applications in such industries as transportation, manufacturing, health care, environmental oversight, and safety and security. WINS combine microsensor technology and low-power signal processing, computation, and low-cost wireless networking in a compact system. Recent advances in integrated circuit technology have enabled construction of far more capable yet inexpensive sensors, radios, and processors, allowing mass production of sophisticated systems linking the physical world to digital data networks [2–5]. Scales range from local to global for applications in medicine, security, factory automation, environmental monitoring, and condition-based maintenance. Compact geometry and low cost allow WINS to be embedded and distributed at a fraction of the cost of conventional wireline sensor and actuator systems. WINS opportunities depend on development of a scalable, low-cost, sensor-network architecture. Such applications require delivery of sensor information to the user at a low bit rate through low-power transceivers. Continuous sensor signal processing enables the constant monitoring of events in an environment in which short message packets would suffice. Future applications of distributed embedded processors and sensors will require vast numbers of devices. Conventional methods of sensor networking represent an impractical demand on cable installation and network bandwidth. Processing at the source would drastically reduce the financial, computational, and management burden on communication system

Intrusion detection in wireless ad-hoc networks

Abstract: As the recent denial-of-service attacks on several major Internet sites have shown us, no open computer network is immune from intrusions. The wireless ad-hoc network is particularly vulnerable due to its features of open medium, dynamic changing topology, cooperative algorithms, lack of centralized monitoring and management point, and lack of a clear line of defense. Many of the intrusion detection techniques developed on a fixed wired network are not applicable in this new environment. How to do it differently and effectively is a challenging research problem. In this paper, we first examine the vulnerabilities of a wireless ad-hoc network, the reason why we need intrusion detection, and the reason why the current methods cannot be applied directly. We then describe the new intrusion detection and response mechanisms that we are developing for wireless ad-hoc networks.

A Framework for Integrated Services Operation over Diffserv Networks

Abstract: The Integrated Services (Intserv) architecture provides a means for the delivery of end-to-end Quality of Service (QoS) to applications over heterogeneous networks. To support this end-to-end model, the Intserv architecture must be supported over a wide variety of different types of network elements. In this context, a network that supports Differentiated Services (Diffserv) may be viewed as a network element in the total end-to-end path. This document describes a framework by which Integrated Services may be supported over Diffserv networks.

Analysis of a local-area wireless network

Abstract: To understand better how users take advantage of wireless networks, we examine a twelve-week trace of a building-wide local-area wireless network. We analyze the network for overall user behavior (when and how intensively people use the network and how much they move around), overall network traffic and load characteristics (observed throughput and symmetry of incoming and outgoing traffic), and traffic characteristics from a user point of view (observed mix of applications and number of hosts connected to by users).Amongst other results, we find that users are divided into distinct location-based sub-communities, each with its own movement, activity, and usage characteristics. Most users exploit the network for web-surfing, session-oriented activities and chat-oriented activities. The high number of chat-oriented activities shows that many users take advantage of the mobile network for synchronous communication with others. In addition to these user-specific results, we find that peak throughput is usually caused by a single user and application. Also, while incoming traffic dominates outgoing traffic overall, the opposite tends to be true during periods of peak throughput, implying that significant asymmetry in network capacity could be undesirable for our users.While these results are only valid for this local-area wireless network and user community, we believe that similar environments may exhibit similar behavior and trends. We hope that our observations will contribute to a growing understanding of mobile user behavior.

Intelligent network selection based on quality of service and applications over different wireless networks

Abstract: A system and method for selecting a wireless network is disclosed. The method relates to selecting a wireless network from plurality of wireless networks. A variation of the invention includes selecting a new platform from a plurality of platforms offered by the current service provider according to a service request from the wireless device. The method comprises determining a requested service associated with the wireless device, determining whether one of the plurality of wireless networks can provide the requested service, and, if one of the plurality of wireless networks can provide the requested service, choosing the one wireless network of the plurality of wireless networks. The method further involves using a variety of parameters in determining which wireless network to choose for servicing the requested service from the wireless device.

MARS: a programmable coordination architecture for mobile agents

Abstract: Mobile agents offer much promise, but agent mobility and Internet openness make coordination more difficult. Mobile Agent Reactive Spaces (MARS), a Linda-like coordination architecture with programming features, can handle a heterogeneous network while still allowing simple and flexible application design.

On TCP performance in a heterogeneous network: a survey

Abstract: Transmission media carrying Internet traffic present a wide range of characteristics, some of which, such as transmission errors, long end-to-end delay, and bandwidth asymmetry, may cause a degradation of the TCP performance. Many works have studied the performance of TCP over these media, most of which focus on a particular network type. In this work we study TCP performance independent of the type of network by considering the different possible characteristics of the connection path. We present the problems and the different proposed solutions. This study permits us to understand the limitations of the actual solutions and the required modifications to let TCP cope with a heterogeneous Internet on an end-to-end basis.

UPnP enabling device for heterogeneous networks of slave devices

Abstract: A bridging device couples an IP (Internet Protocol) network to one or more non-IP networks, in order to facilitate the control of non-UPnP (Universal Plug and Play) devices by a UPnP controller on the IP network. Each of the non-IP slave networks may employ different network technologies, such as USB, Bluetooth, HAVi, Home API, HomeRF, X-10, Jini, and so on. The bridging device includes an IP network interface for receiving commands and requests from the UPnP controller, and one or more slave network interfaces that transform the received commands and requests into device and network specific commands and requests. These device and network specific commands and requests are communicated to the controlled non-UPNP device, via the slave network, using the slave network's protocol. The bridging device also communicates event status messages to the UPnP controller, corresponding to the non-UPnP devices' response to the UPnP controller's commands and requests. The bridging device also includes enabling logic to support the UPNP addressing, discovery, and description processes for each of the devices on the non-IP network. To minimize the storage requirements at the bridging device, the bridging device is configure to use a file server that is also resident on an IP network, wherein the file server contains the detailed information required to effect the appropriate UPnP addressing, discovery, and description processes, and other information-laden tasks, as required.

RMX: reliable multicast for heterogeneous networks

Abstract: Although IP multicast is an effective network primitive for best-effort, large-scale, multi-point communication, many multicast applications such as shared whiteboards, multi-player games and software distribution require reliable data delivery. Building services like reliable sequenced delivery on top of IP multicast has proven to be a hard problem. The enormous extent of network and end-system heterogeneity in multipoint communication exacerbates the design of scalable end-to-end reliable multicast protocols. In this paper, we propose a radical departure from the traditional end-to-end model for reliable multicast and instead propose a hybrid approach that leverages the successes of unicast reliability protocols such as TCP while retaining the efficiency of IP multicast for multi-point data delivery. Our approach splits a large heterogeneous reliable multicast session into a number of multicast data groups of co-located homogeneous participants. A collection of application-aware agents-reliable multicast proxies (RMX)-organizes these data groups into a spanning tree using an overlay network of TCP connections. Sources transmit data to their local group, and the RMX in that group forwards the data towards the rest of the data groups. RMX use detailed knowledge of application semantics to adapt to the effects of heterogeneity in the environment. To demonstrate the efficacy of our architecture, we have built a prototype implementation that can be customized for different kinds of applications.

IP-based access network infrastructure for next-generation wireless data networks

Abstract: Next-generation wireless network standards are currently being defined. The access network architectures have several specialized components tailored for their respective wireless link technologies, even though the services provided by these different wireless networks are fairly similar. We propose a homogeneous IP-based network as a common access network for the different wireless technologies. The IP-based access network uses the Internet standard, Mobile IP, to support macro-mobility of mobile hosts, and HAWAII to support micro-mobility and paging functionality of current wireless networks. We also illustrate how the proposed IP-based solution can interwork with existing infrastructure so that deployment can be incremental.

System and method for wireless hot-synchronization of a personal digital assistant

Abstract: A wireless hot-sync system includes a personal digital assistant (PDA) having a transceiver for communicating over a wireless link, a hot-sync server having a transceiver for communicating with the PDA over the wireless link and a network interface for communicating with devices on a local area network (LAN), and a host system connected to the LAN. Upon receipt a hot-sync request from the PDA via the wireless link, the hot-sync server opens a network connection with the host system to establish a wireless hot-sync channel. The PDA and the host system exchange packets containing synchronization data, which is used by each device to update a local data set to bring it into correspondence with the data set of the other device. Upon completion of the wireless hot-sync, the hot-sync server closes the network connection and disables the hot-sync channel.

Mobile Agents: Motivations and State-of-the-Art Systems

Abstract: A mobile agent is an executing program that can migrate, at times of its own choosing, from machine to machine in a heterogeneous network. On each machine, the agent interacts with stationary service agents and other resources to accomplish its task. In this chapter, we first make the case for mobile agents, discussing six strengths of mobile agents and the applications that benefit from these strengths. Although none of these strengths are unique to mobile agents, no competing technique shares all six. In other words, a mobile-agent system provides a single general framework in which a wide range of distributed applications can be implemented efficiently and easily. We then present a representative cross-section of current mobile-agent systems.

Reliability and survivability of wireless and mobile networks

Abstract: The world is becoming more dependent on wireless and mobile services, but the ability of wireless network infrastructures to handle the growing demand is questionable. As wireless and mobile services grow, weaknesses in network infrastructures become clearer. Failures not only affect current voice and data use but could also limit emerging wireless applications such as e-commerce and high-bandwidth Internet access. As wireless and mobile systems play greater roles in emergency response, including 911 and enhanced 911 services, network failures take on life-or-death significance. Therefore, in addition to directing some attention to designing survivable wireless and mobile networks, developers must also keep in mind that increasingly pervasive and demanding services will further escalate the importance of reliability and survivability requirements. The authors explain several options providers must consider to decrease the number of network failures and to cope with failures when they do occur.

Handover between wireless telecommunication networks/systems

Abstract: A method and a wireless telecommunication system of performing network-assisted handover of calls between a serving network and another wireless network that employs communication protocols different from those of the serving network. A message is sent from a mobile station of a user to the serving wireless network, which includes an indication that the mobile station is capable of communicating with the neighboring wireless network. Information relating to the communication characteristics of the neighboring wireless network is also sent from the serving wireless network to the mobile station. Using the information relating to the communication characteristics of the neighboring wireless network, the mobile station receives radio signals from the neighboring wireless network. The quality of the radio signals between the mobile station and the neighboring wireless network is measured. The serving wireless network sends a message to the neighboring wireless network to request a handover of the communication transaction when the quality of the radio signals between the neighboring wireless network and the mobile station meets a predetermined minimum threshold. Then a handover of the communication transaction from the serving wireless network to the neighboring wireless network is executed after the neighboring wireless network has established a communication channel for the mobile station pursuant to the handover request.

2K: a distributed operating system for dynamic heterogeneous environments

Abstract: The first decades of the new millennium will witness an explosive growth in the number and diversity of networked devices and portals We foresee high degrees of mobility, heterogeneity, and interactions among computing devices connected to global networks While previous research in distributed operating systems solved many problems related to resource management, they seldom addressed the problems of heterogeneity and dynamic adaptability On the other hand, middleware solutions, like CORBA and Java/Jini, solve part of the heterogeneity problem by permitting seamless communication among different platforms But, they do not address dynamic resource management and adaptability for applications requiring high-performance distributed computing This paper presents 2K, an integrated operating system architecture that addresses the problems of resource management in heterogeneous networks, dynamic adaptability and configuration of component-based distributed applications

Hierarchical routing for multi-layer ad-hoc wireless networks with UAVs

Abstract: Routing scalability in multi-hop wireless networks faces many challenges. The spatial concurrency constraint on nearby nodes sharing the same channel is the fundamental limitation. A previous theoretical study shows that the throughput furnished to each user is rapidly reduced as network size is increased. In order to solve this problem, we extended the hierarchical state routing scheme to a hierarchical multilayer environment. With the hierarchical approach, many problems caused by "flat" multi-hopping disappear. In the real battlefield, a multi-level physical heterogeneous network with UAVs provides an ideal support for the multi-area theater with a large number of fighting units. Extended hierarchical state relating (EHSR) shows very promising results in this hierarchical infrastructure.

Terminal roaming operations between intergenerational wireless networks

Abstract: A method for supporting operation of mobile terminal having a subscription in a packet switched wireless network within a legacy wireless network when the mobile terminal roams into the service area of the legacy network. The mobile terminal sends an attach request to a support node of the legacy wireless network. The legacy wireless network then authenticates the mobile terminal. Next, the support node of the legacy wireless network interacts with the packet switched wireless network to receive the mobile terminal's subscriber data. The home subscriber service function of the packet switched wireless network then interacts with a prior support node to cancel the wireless terminals prior location. The support node of the legacy wireless network next requests a visitor location register of the legacy wireless network to register the mobile terminal. The visitor location register of the legacy wireless network then interacts with the packet switched wireless network to register the mobile terminal within the legacy wireless network. The visitor location register of the legacy wireless network next acknowledges to the support node that the mobile terminal has been registered within the legacy wireless network. Finally, the support node of the legacy wireless network acknowledges the attach request to the mobile terminal. In another operation, a packet switched wireless network services packet switched operations for a packet switched mobile terminal.

Optimal scheduling for streaming of scalable media

Abstract: Scalable, or layered, media representation appears to be more suitable for transmission over the current heterogeneous networks. In this paper we study the problem of scalable layered streaming media delivery over a lossy channel. The goal is to find an optimal transmission policy to achieve the best playback quality at the client end. The problem involves some trade-offs such as time-constrained delivery and data dependencies. For example, a layer should be dropped before transmission if it already has a delay such that it cannot be played before its scheduled time. Moreover, less important layers with near-playback-time may also be dropped or delayed for delivery in order to save bandwidth for other layers with a high priority. We propose a framework for scalable streaming media delivery, that involves a novel scheduling algorithm called Expected runtime Distortion Based Scheduling (EDBS) which decides the order in which packets should be transmitted in order to improve client playback quality in the presence of channel losses. A fast greedy search algorithm is presented that achieves almost the same performance as an exhaustive search technique (98% of the time it results in the same schedule) with very low complexity and is applicable for real-time application.

Energy/throughput tradeoffs of TCP error control strategies

Abstract: Today's universal communications increasing involve mobile and battery-powered devices (e.g. hand-held, laptop, IP-phone) connected over wired and wireless networks. Energy efficiency, as well as throughput are becoming service characteristics of dominant importance in communication protocols. The wide applicability of IP-networks/devices, and the wide range of TCP-based applications, have rendered TCP the de facto reliable transport protocol standard not only for wired, but also for wireless and mixed (wired/wireless) communications. TCP's congestion control algorithms have been refined to achieve higher throughput. Even with these modifications, however, TCP versions do not incorporate a flexible error recovery strategy that is responsive to distinct environmental characteristics and device constraints. We have compared the energy- and throughput-efficiency of TCP error control strategies based on results gathered from our implementation of TCP Tahoe, Reno, and New Reno. We show that, depending on the frequency and duration of the error, each demonstrates appropriate behavior under specific circumstances, with Tahoe more-or-less the most energy conserving of the three. None of them, however, possesses a clear-cut overall advantage that would render it the version of choice for wired/wireless heterogeneous networks.

Wireless Local Area Networks

Abstract: A press, including a frame, a pair of rigid side structures, means for pivotally connecting the side structures to said frame, a pair of rotor assemblies having confronting faces arranged at an angle to each other and defining a pressing zone, each of the rotor assemblies being mounted for rotation in a respective side member, means interconnecting the side structures to one another and serving to apply yieldable force to urge the side structures toward one another, the improvements basically comprising means for adjusting the pivotal connecting means to vary the pressing action of the rotor assemblies, and a hydrostatic bearing means, which may be used in association with an annular thrust bearing, for minimizing the friction between the rotor assemblies and the side structures.

PM2: a high performance communication middleware for heterogeneous network environments

Abstract: This paper introduces a high performance communication middle layer, called PM2, for heterogeneous network environments. PM2 currently supports Myrinet, Ethernet, and SMP. Binary code written in PM2 or written in a communication library, such as MPICH-SCore on top of PM2, may run on any combination of those networks without re-compilation. According to a set of NAS parallel benchmark results, MPICH-SCore performance is better than dedicated communication libraries such as MPICH-BIP/SMP and MPICH-GM when running some benchmark programs.

System, method and program for enabling an electronic commerce heterogeneous network

Abstract: In a system, method and program for enabling electronic commerce, a network host provides a service using the network to a network client in exchange for payment while maintaining anonymity and security. An embodiment of the system includes a networked financial resolution center, which is operably coupled to the network host and network client. The financial resolution center is adapted to maintain financial accounts for the network host and the network client. The financial resolution center is further adapted to resolve the payment for the service is further adapted to maintain confidentiality as to the identities of the network client and the network host. An embodiment of the method includes receiving a charge for the network host, assigning the charge to the network client, and resolving the charge via the financial accounts for the network client and network host while maintaining confidentiality.

Integration of mobile agents with SNMP: why and how

Abstract: Mobile agents have been proposed as a solution to the problem of the management of increasingly heterogeneous networks. However, the proposed solutions often ignore the value of legacy solutions and protocols. This paper extends an existing mobile agent framework targeted at network management with an architecture and design for integration with an SNMP agent. Brief descriptions of the use of this solution for the provisioning of ATM permanent virtual circuits and providing a mobile agent MIB are also provided.

A scalable SNMP-based distributed monitoring system for heterogeneous network computing

Abstract: Traditional centralized monitoring systems do not scale to present-day large, complex, network-computing systems. Based on recent SNMP standards for distributed management, this paper addresses the scalability problem through distribution of monitoring tasks, applicable for tools such as SIMONE (SNMP-based monitoring prototype implemented by the authors).Distribution is achieved by introducing one or more levels of a dual entity called the Intermediate Level Manager (ILM) between a manager and the agents. The ILM accepts monitoring tasks described in the form of scripts and delegated by the next higher entity. The solution is flexible and integratable into a SNMP tool without altering other system components. A testbed of up to 1024 monitoring elements is used to assess scalability. Noticeable improvements in the round trip delay (from seconds to less than one tenth of a second) were observed when more than 200 monitoring elements are present and as few as two ILM's are used.

Call agents and systems and methods for providing emergency call services on heterogeneous networks

Abstract: Call agents methods and systems are provided for providing emergency services on a heterogeneous network, such as a cable system, having a bandwidth. A request for telephony service is received wherein the telephony service will be provided over the cable system. It is determined if a portion of the bandwidth of the cable system which is allocated to telephony is fully utilized and if the request for telephony service is a request for emergency service. A portion of the bandwidth of the cable system is obtained to provide the requested telephony service if the request for telephony service is a request for emergency service and the portion of the bandwidth of the cable system which is allocated to telephony is fully utilized. The requested emergency service is provided using the obtained portion of the bandwidth of the cable system.

Differentiated services and integrated services use of MPLS

Abstract: All the new emerging QoS service architectures are motivated by the desire to improve the overall performance of IP networks. Integrated services (Intserv), differentiated services (Diffserv), MultiProtocol Label Switching (MPLS) and constraint-based routing are all technologies starting to coexist together in today's Internet to provide means for the delivery of end-to-end QoS to applications over heterogeneous networks. We propose DRUM (Diffserv and RSVP/intserv Use of MPLS), an architecture that delivers end-to-end service guarantees for both Diffserv and Intserv networks, where part of the underlying technology used for IP transport is MPLS using Diffserv-like mechanisms for QoS provision. We also show how traffic engineering can ameliorate service differentiation, and illustrate how interoperability can be achieved between DRUM and neighboring Diffserv and Intserv networks.

Hierarchical cache design for enhancing TCP over heterogeneous networks with wired and wireless links

Abstract: In this paper, we propose a two-layer hierarchical cache architecture for enhancing TCP performance over heterogeneous networks with both wired and wireless links. A new network-layer protocol, called New Snoop, is designed. The main idea is to cache the unacknowledged packets at both the mobile switch center (MSG) and base station (BS), thus forming a two-layer cache hierarchy. If a packet is lost due to transmission errors in the wireless link, the BS takes the responsibility to recover the loss. When a handoff occurs during a TCP connection session, the packets cached in MSC can help to minimize the latency of retransmissions due to temporal disconnection. Simulation results show that using New Snoop is significantly more robust in dealing with unreliable wireless inks and handoffs as compared with the Snoop scheme (Balakrishnan et al. 1995) as well as other existing TCP enhancements.

Method and system for utilizing subscriber status and location information in a wireless network

Abstract: A wireless communication system has a plurality of information server computers coupled by a wired network (100) and a plurality of wireless mobile devices (106,134,136) that communicate using a wireless network (102), each mobile device including a network browser, a display and a processor. A server (114) couples the mobile devices to the information server computers through the wireless network and the wired network. When a particular one of the network browsers desires to access a resource from one of the information server computers, the server determines whether a resource request therefrom is to an information server computers that provides spatial-related information and, if so, determines an appropriate location of interest and produces a revised resource request. The device (106) can therefore, for example, cause a display screen thereof (116) to display an identifier of at least one other wireless device and a status indicator pertaining thereto or the location thereof.

Effective load sharing on heterogeneous networks of workstations

Abstract: We consider networks of workstations which are not only time-sharing, but also heterogeneous with a large variation in the computing power and memory capacities of different workstations. Many load sharing schemes mainly target sharing CPU resources, and have been intensively evaluated in homogeneous distributed environments. However the penalties of data accesses and movement in modern computer systems, such as page faults, have grown to the point where the overall performance of distributed systems cannot be further improved without serious considerations concerning memory resources in the design of load sharing policies. Considering both system heterogeneity and effective usage of memory resources, we design and evaluate load sharing policies in order to minimize both CPU idle times and the number of page faults in heterogeneous distributed systems. Conducting trace-driven simulations, we show that load sharing policies considering both CPU and memory resources are robust and effective in heterogeneous systems. We also show that the functionality and the nature of load sharing policies are quite independent on several memory demand distributions of workloads.

Matrix-matrix multiplication on heterogeneous platforms

Abstract: In this paper, we address the issue of implementing matrix-matrix multiplication on heterogeneous platforms. We target two different classes of heterogeneous computing resources: heterogeneous networks of workstations, and collections of heterogeneous clusters. Intuitively, the problem is to load balance the work with different-speed resources while minimizing the communication volume. We formally state this problem and prove its NP-completeness. Next we introduce a (polynomial) column-based heuristic, which turns out to be very satisfactory: we derive a theoretical performance guarantee for the heuristic, and we assess its practical usefulness through MPI experiments.