High-speed Wide Area Networks Research Articles

Falcon: Fair and Efficient Online File Transfer Optimization

Research networks provide high-speed wide-area network connectivity between research and education institutions to facilitate large-scale data transfers. However, scalability issues of legacy transfer applications such as scp and FTP hinder the effective utilization of these networks. Although researchers extended the legacy transfer applications to increase their performance by exploiting I/O and network parallelism, these solutions necessitate users to fine-tune parallelism level, a task that is challenging even for experienced users due to the dynamic nature of networks. In this paper, we propose an online optimization algorithm, Falcon, to tune the degree of parallelism for file transfers to maximize transfer throughput while keeping system overhead at a minimum. As research networks are shared infrastructures, we introduce a game theory-inspired novel utility function to evaluate the performance of various parallelism levels such that competing transfers are guaranteed to converge to a fair and stable solution. We assessed the performance of Falcon in isolated and production high-speed networks and found that it can discover optimal transfer parallelism in as little as 20 seconds and outperform the state-of-the-art solutions by more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2\times$</tex-math></inline-formula> . Moreover, Falcon is guaranteed to converge to Nash Equilibrium when multiple transfers compete for the same resources with the help of its game theory-inspired utility function. Finally, we demonstrate that Falcon can also be used as a central transfer scheduler to speed up convergence time, increase stability, and enforce system/user-level resource limitations in shared networks.

Design of CPW antenna for network applications

The novel CPW antenna design consists of monopole, which can used for High speed wide area or local area corporate networks and Video &amp; CCTV surveillance networks and Long-range Rural connectivity. This antenna has been designed with design size parameters of 59.5(L) x 30 (W) x 1.6-(H) mm2, the dielectric constant of FR4 substrate is 4.4, and loss tangent of 0.002 is used. The resonant frequency range of this proposed antenna is 5.85 - 6.6 GHz with return loss above of -10dB achieved. The peak gain of this antenna is 5.5dBi and in addition the S, Z-parameters, VSWR, 2D &amp; 3D radiation pattern are also derived. Good results are achieved after simulation.

Evolution of TCP in High Speed Networks

TCP congestion control protocols have low performances in high speed wide area networks mainly because their slow response with large congestion windows. This TCP behavior has initiated new design phase of alternative protocols that provide improved traffic utilization in high bandwidth delay product networks. The paper presents survey of various high speed sender side congestion control proposals that preserve the fundamental host to host principle. Solutions focus on variety of problems occurring in high speed environment with intention to eliminate congestion collapses and to ensure effective resource utilization. Internet data transfer does not depend only on that how TCP will utilize the network capacity, we have to stress that TCP must cooperate with existing transmitting data protocols through the same network in order to assure fair resource sharing. Part of the paper scope are state of the art high speed TCP proposals, we explore their congestion control techniques, strengths, weaknesses and we try to detect future TCP development possibilities.

Development of A New Efficient Routing Scheme for WiMAX Mesh Networks

The emerging WiMAX (Worldwide Interoperability for Microwave Access) technology (IEEE 802.16) can offer low-cost, high speed and long- range communications. The WiMAX supports a point-to- multipoint (PMP) topology and a mesh topology. A WiMAX network is composed of a Base Station (BS) and multiple Subscriber Station (SS). A BS is the mother node and the SS is the child node, though a SS can also be a mother node of a SS if the child node is connected with him to reach to the BS. The BS serves as a gateway connecting to external networks such as the Internet. Number of nodes situated beside a node is called neighbor nodes. In PMP architecture, there is a multi-hop mesh that can be used to gain the high speed wide area network. Again in mesh topology, it increases the wireless coverage and reconfigures ability. In this mode performance depends on a good routing and scheduling protocol. Routing is the way by which a SS will connect with the BS. A good and efficient routing algorithm along with a scheduling algorithm can improve the total network performance significantly. Scheduling algorithm gives the time slot to all SS in a way so that a SS can transmit data or signal in that time slot. There are many research scopes on IEEE 802.16 mesh network especially in routing and scheduling protocol. The purpose of our thesis work is to propose a new routing algorithm to maximize the performance of the network.

A DECENTRALIZED DYNAMIC LOAD BALANCING FOR COMPUTATIONAL GRID ENVIRONMENTS

With the rapid development of high-speed wide-area networks and powerful yet low-cost computational resources, grid computing has emerged as an attractive computing paradigm. The computational grid is a new parallel and distributed computing paradigm that provides resources for large scientific computing applications. The main techniques that are most suitable to cope with the dynamic nature of the grid are the effective utilization of grid resources and the distribution of application load among multiple resources in a grid environment. This paper addresses the problem of scheduling and load balancing in a grid environment. A Decentralized Dynamic load balancing algorithm is proposed which combines the strong points of neighbor based and cluster based load balancing techniques. This algorithm estimates system parameters such as resource processing capacity, load on each resource and transfer delay for scheduling and load balancing. A set of simulation experiments show that the proposed algorithm provides significant performance over existing ones.

Energy Conservation In Computational Grids

With the increasing development of high-speed wide-area networks and powerful though low cost computational resources, grid computing has emerged as an attractive computing paradigm.With recent advances in computing, the scope of grid computing has been expanded to include mobile and pervasive devices. Grids have become one of the highest consumers of energy. High performance computing is achieved at the cost of energy consumption. Increasing the performance of computer systems requires increasing number of resources which leads to higher power consumption and it creates negative impact on environment. Idle sites in grid are direct sources of energy waste. Saving energy causes two direct advantages: financial and environmental cost reduction and sustainability. With the Grid becoming a viable high-performance alternative to the traditional supercomputing environment, various aspects of Grid resource utilization which can help in energy conservation are gaining significance. In this paper we explore the possibility of reduction in energy consumption of a grid of heterogeneous computers by making use of different power states of cpu.

A Hierarchical Load Balancing Policy for Grid Computing Environment

With the rapid development of high-speed wide-area networks and powerful yet low-cost computational resources, grid computing has emerged as an attractive computing paradigm. It provides resources for solving large scientific applications. It is typically composed of heterogeneous resources such as clusters or sites at different administrative domains connected by networks with widely varying performance characteristics. The service level of the grid software infrastructure provides two essential functions for workload and resource management. To efficiently utilize the resources at these environments, effective load balancing and resource management policies are fundamentally important. This paper addresses the problem of load balancing and task migration in grid computing environments. We propose a fully decentralized two-level load balancing policy for computationally intensive tasks on a heterogeneous multi-cluster grid environment. It resolves the single point of failure problem which many of the current policies suffer from. In this policy, any site manager receives two kinds of tasks namely, remote tasks arriving from its associated local grid manager, and local tasks submitted directly to the site manager by local users in its domain, which makes this policy closer to reality and distinguishes it from any other similar policy. It distributes the grid workload based on the resources occupation ratio and the communication cost. The grid overall mean task response time is considered as the main performance metric that need to be minimized. The simulation results show that the proposed load balancing policy improves the grid overall mean task response time.

A Push-Based Prefetching for Remote Caching RAM Grid

As an innovative grid computing technique for sharing the distributed memory resources in a high-speed widearea network, RAM Grid exploits the distributed computing nodes, and provides remote memory for the user nodes which are short of memory. The performance of RAM Grid is constrained with the expensive network communication cost. In order to hide the latency of remote memory access and improve the performance, the authors proposed the push-based prefetching to enable the memory providers to push the potential useful pages to the user nodes. For each provider, it employs sequential pattern mining techniques, which adapts to the characteristics of memory page access sequences, on locating useful memory pages for prefetching. They have verified the effectiveness of the proposed method through trace-driven simulations.

Scheduling Policies for Processor Coallocation in Multicluster Systems

Building multicluster systems out of multiple, geographically distributed clusters interconnected by high-speed wide-area networks can provide access to a larger computational power and to a wider range of resources. Jobs running on multiclusters and, more generally, in grids, may require (processor) coallocation, i.e., the simultaneous allocation of resources (processors) in different clusters or subsystems of a grid. In this paper, we propose four scheduling policies for processor coallocation in multiclusters, and we assess with simulations their performance under a wide variety of parameter settings. In particular, in our simulations we use synthetic workloads and workloads derived from the logs of actual systems and from runtime measurements. We conclude that although coallocation makes scheduling more difficult and the wide-area communication critically impacts the performance, there is a wide range of realistic applications that may benefit from coallocation. However, unrestricted coallocation is not recommended: Limiting the total job size or the number or the sizes of their components improves performance.

UDT: UDP-based data transfer for high-speed wide area networks

In this paper, we summarize our work on the UDT high performance data transport protocol over the past four years. UDT was designed to effectively utilize the rapidly emerging high-speed wide area optical networks. It is built on top of UDP with reliability control and congestion control, which makes it quite easy to install. The congestion control algorithm is the major internal functionality to enable UDT to effectively utilize high bandwidth. Meanwhile, we also implemented a set of APIs to support easy application implementation, including both reliable data streaming and partial reliable messaging. The original UDT library has also been extended to Composable UDT, which can support various congestion control algorithms. We will describe in detail the design and implementation of UDT, the UDT congestion control algorithm, Composable UDT, and the performance evaluation.

Broadband-Facilitated Inter-WLAN Mobility Architecture

The existing WLAN architecture does not have the capabilities to leverage the wired and wireless broadband-accessed network control for the Inter-WLAN mobility. This paper presents a broadband-facilitated inter-WLAN mobility system architecture including its realization with the wired and wireless broadband-accessed network control for the WLAN mobility management. The proposed broadband-based inter-WLAN mobility management concept has changed the notion of the traditional WLAN mobility. Secondly, an implementation of the distribution system with broadband-accessed central network control for the IEEE 802.11 inter-WLAN mobility along with its management protocol is presented. In addition, this paper provides the modification to the enhanced IAPP protocol signaling messaging required for the broadband-facilitated WLAN mobility management. Finally, simulation experimental results for the proposed inter-WLAN communications architecture’s performance vs. WLAN mobility management performance employing standard and optimized MIP are presented. We believe that the proposed architecture would greatly enhance the Inter-WLAN IP mobility performance. This paper serves as a foundation work for future research in inter-WLAN mobility management using broadband, wired and wireless that integrates high-speed wide area network and WLANs.

Simple Available Bandwidth Utilization Library for High-Speed Wide Area Networks

The growth of high-speed wide area networks (WANs) has enabled the emergence of new classes of data intensive, wide area computing applications, such as the remote analysis and exploration of data and distributed data mining. The de facto standard for reliable data transfers is the Transmission Control Protocol (TCP). Despite improvements in TCP over the years (to reduce overhead and achieve higher throughput), it is still a common experience for the end-to-end data rates of wide area data mining and data analysis applications to be inefficient. This paper introduces a library called SABUL (Simple Available Bandwidth Utilization Library) which merges features of UDP and TCP to produce a light-weight protocol with flow control, rate control and reliable transmission mechanisms that is designed for data intensive applications over wide area high performance networks. In this paper, we describe the library and give experimental evidence of its effectiveness.

Performance Evaluation of MulTCP in High-Speed Wide Area Networks

SUMMARY It is reported that TCP does not perform well in highspeed wide area networks. Because MulTCP behaves like the aggregate of N TCP flows, MulTCP can be used to achieve throughputs of 1 Gbps or more. However, no performance evaluation of MulTCP in high-speed wide area networks has been published. Computer simulations are used to evaluate the performance of MulTCP. The results clarify that synchronized packet losses greatly impact the performance of MulTCP.

Quanta: a toolkit for high performance data delivery over photonic networks

Quanta is a cross-platform adaptive networking toolkit for supporting the data delivery requirements of interactive and bandwidth intensive applications, such as Amplified Collaboration Environments. One of the unique goals of Quanta is to provide applications with the ability to provision optical pathways (commonly referred to as Lambdas) in dedicated photonic networks. This paper will introduce Quanta’s architecture and capabilities, with particular attention given to its aggressive and predictable high performance data transport scheme called Reliable Blast UDP (RBUDP). We provide an analytical model to predict RBUDP’s performance and compare the results of our model against experimental results performed over a high speed wide-area network.

Scalable TCP

TCP congestion control can perform badly in highspeed wide area networks because of its slow response with large congestion windows. The challenge for any alternative protocol is to better utilize networks with high bandwidth-delay products in a simple and robust manner without interacting badly with existing traffic. Scalable TCP is a simple sender-side alteration to the TCP congestion window update algorithm. It offers a robust mechanism to improve performance in highspeed wide area networks using traditional TCP receivers. Scalable TCP is designed to be incrementally deployable and behaves identically to traditional TCP stacks when small windows are sufficient. The performance of the scheme is evaluated through experimental results gathered using a Scalable TCP implementation for the Linux operating system and a gigabit transatlantic network. The preliminary results gathered suggest that the deployment of Scalable TCP would have negligible impact on existing network traffic at the same time as improving bulk transfer performance in highspeed wide area networks.

Multicast group membership management

Multicast services, assisted by special hardware, are being considered as a part of high-speed wide-area networks (WANs) in order to support new generations of multiuser applications. This paper describes an application multicast service for high-speed WANs which is capable of exploiting multicast hardware. Indeed, this research was conducted in context of the spanning tree hardware structure of PARIS and of plaNET, the pioneering broadband experimental networks that predated ATM. The results of this research were also included in IBM's ATM, called Networking BroadBand Services (NBBS).We achieve modularity and low cost by assigning to distinct components the separate problems of: 1) naming groups; 2) finding group members in a network; 3) configuring multicast hardware; and 4) delivering multicast messages in sequence. This modularity enables, for example, both the multicast to a group to which the user initiates the joining (formed by using 1 and 2 above), on one hand, and to groups computed by the source on the other hand. We give the overall organization of our service and then describe in detail the methods used to solve the first two of the subproblems.

Authenticity and integrity of digital mammography images.

Data security becomes more and more important in telemammography which uses a public high-speed wide area network connecting the examination site with the mammography expert center. Generally, security is characterized in terms of privacy, authenticity and integrity of digital data. Privacy is a network access issue and is not considered in this paper. We present a method, authenticity and integrity of digital mammography, here which can meet the requirements of authenticity and integrity for mammography image (IM) transmission. The authenticity and integrity for mammography (AIDM) consists of the following four modules. 1) Image preprocessing: To segment breast pixels from background and extract patient information from digital imaging and communication in medicine (DICOM) image header. 2) Image hashing: To compute an image hash value of the mammogram using the MD5 hash algorithm. 3) Data encryption: To produce a digital envelope containing the encrypted image hash value (digital signature) and corresponding patient information. 4) Data embedding: To embed the digital envelope into the image. This is done by replacing the least significant bit of a random pixel of the mammogram by one bit of the digital envelope bit stream and repeating for all bits in the bit stream. Experiments with digital IMs demonstrate the following. 1) In the expert center, only the user who knows the private key can open the digital envelope and read the patient information data and the digital signature of the mammogram transmitted from the examination site. 2) Data integrity can be verified by matching the image hash value decrypted from the digital signature with that computed from the transmitted image. 3) No visual quality degradation is detected in the embedded image compared with the original. Our preliminary results demonstrate that AIDM is an effective method for image authenticity and integrity in telemammography application.

Telepathology networking in VISN-12 of the Veterans Health Administration.

The Veterans Integrated Service Network (VISN)-12, headquartered in Chicago, has implemented a telepathology network between the eight VISN-12 hospital laboratories and Loyola University Medical School linked by an economical, high-speed wide-area network (WAN). Implementation of the WAN has reduced monthly telecommunications costs in VISN-12 by approximately 67%. In addition to telepathology, the WAN enables real-time teleradiology (general, computer tomography, and ultrasound), telefluoroscopy, telenuclear medicine imaging, telepsychiatry, and other forms of teleconsultation. Current applications of telepathology in VISN-12 include: primary diagnosis and consultation in surgical pathology, interpretation of serum protein electrophoresis and immunofixation gels, provision of support for consolidated microbiology laboratories, review of problematic peripheral blood smears, and distance learning. We have learned a variety of lessons from telepathology. The enthusiasm and technical skill of providers are essential for success. As well, frequent communication and rapid technical support are necessary. Finally, in a supportive environment, telepathology is a tool that can help bring together clinical laboratories with shared missions and goals.

Performance analysis of a scaleable design for replicating file collections in wide-area networks

Mirroring file collections in the global Internet is widely practiced with a recent study estimating the number of WWW hosts with mirrored content at 10% of all WWW hosts. Conventional mirroring tools, however, are not well-suited for the large-scale multiple-site replication services envisioned by projects such as the Internet2 Distributed Storage Infrastructure (I2-DSI) project. This paper presents a scaleable design for the automated synchronization of large collections of files replicated across multiple hosts, as in I2-DSI, and outlines of how the design has been realized using rsync+, a modification to the popular open-source mirroring tool, rsync. A performance study based on an instrumented mirror usingrsync + empirically characterizes server-side processing costs under realistic, large-scale workloads, and supplementary measurements of network throughput across Internet2 links illustrate the achievable network performance in a high-speed wide-area network. These experimental results confirm the validity of scalability arguments for the design, uncover key system parameters for rsync+ that must be tuned for efficient operation, and indicate the limitations of TCP-only transport solutions as the number of mirror sites grows.

Software infrastructure for the I-WAY metacomputing experiment

High-speed wide-area networks are expected to enable innovative applications that integrate geographically distributed, high-performance computing, database, graphics and networking resources. However, there is as yet little understanding of the higher-level services required to support these applications, or of the techniques required to implement these services in a scalable, secure manner. We report on a large-scale prototyping effort that has yielded some insights into these issues. Building on the hardware base provided by the I-WAY, a national-scale asynchronous transfer mode (ATM) network, we developed an integrated management and application programming system, called I-Soft. This system was deployed at most of the 17 I-WAY sites and used by many of the 60 applications demonstrated on the I-WAY network. In this paper we describe the I-Soft design and report on lessons learned from application experiments. We focus on four novel concepts that we believe may have relevance to future, similar systems: point of presence machines as a means of simplifying implementation and management; scheduler proxies to integrate local schedulers to computational resource brokers; authentication proxies to provide a uniform authentication environment across multiple administrative domains; and network-aware parallel programming tools to hide heterogeneity and improve performance in heterogeneous environments. Lessons learned in building I-Soft have motivated subsequent research and development efforts in the Globus project. © 1998 John Wiley & Sons, Ltd.