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Small-scale commercial rollouts of Cellular-IoT (C-IoT) networks have started globally since last year. However, among the plethora of low power wide area network (LPWAN) technologies, the cost-effectiveness of C-IoT is not certain for IoT service providers, small and greenfield operators. Today, there is no known public framework for the feasibility analysis of IoT communication technologies. Hence, this paper first presents a generic framework to assess the cost structure of cellular and non-cellular LPWAN technologies. Then, we applied the framework in eight deployment scenarios to analyze the prospect of LPWAN technologies like Sigfox, LoRaWAN, NB-IoT, LTE-M, and EC-GSM. We consider the inter-technology interference impact on LoRaWAN and Sigfox scalability. Our results validate that a large rollout with a single technology is not cost-efficient. Also, our analysis suggests the rollout possibility of an IoT communication Technology may not be linear to cost-efficiency.

Nowadays, due to modernization or advancement in the Internet of Things (IoT) especially in the Healthcare area, we want to take care of our elders with some monitoring equipment, and the Internet of Things can play a significant role in it. The motivation of writing this paper is to collect the information of various existing Internet of Things Architecture and Communication Techniques used in Healthcare Monitoring System to observe that how efficiently, different researchers have used it. So we have studied different real-time health monitoring system based on diseases which are common in elderly people like diabetes, blood pressure, heart disease, sleep apnea, and cancer, etc. In this real-time health monitoring system, researchers introduced many new measures, communication techniques like ZigBee, Long-Range Wide Area Network (LoRawan), Radio Frequency Identification (RFID). Apart from this, it was also observed that remote monitoring system in Healthcare is incomplete without data processing and early prediction in such diseases. Though, Machine learning provides efficient techniques to extract knowledge from diagnostic medical datasets collected from the patients. That is why we highlighted the current role of various Machine Learning algorithms like Support Vector Machine, K-Nearest Neighbor, Random Forest, etc., for processing of Healthcare data and also helpful to predict the output more precisely.

Existing advanced metering infrastructures (AMI) use three levels of bi-directional communication between the customer and utility. Given the increase of the available amount of data provided by smart meters in smart grid, existing AMI network may not have the required bandwidth to perform the monitoring and control in real time. The increase of the AMI network bandwidth is very expensive. On the other hand, the internet employs a set of universal communication protocols and provides a wide communication bandwidth. A new internet-based advanced metering and control infrastructure (IBAMCI) is provided in this paper. It uses only two level of communication: the local area network (LAN) and the internet. Both LAN and internet platforms already exist in most consumer’s premise. The internet infrastructure when utilized eliminates the need for expensive bandwidth upgrades to the utility wide area network (WAN). The proposed IBAMCI is equipped with an integrated internet/cloud-based data management and control server, a user interface and display module. The consumer power consumption can be displayed from anywhere using the internet. Because the proposed IBAMCI offloads the utility WAN, real-time smart grid load monitoring and control becomes possible without delays. Simulations were carried out to illustrate the benefit of the proposed IBAMCI in monitoring large number of customer loads in real time. For existing AMIs, whenever the communication bandwidth becomes insufficient, the only option is to increase the utility network bandwidth, which can be prohibitively expensive.

LTE Machine Type Communication Category M1 [LTE CAT M (or M1)] is a 3GPP Low Power Wide Area Network most suitable for IoT devices that need low data rates, deep coverage, low-cost, and, most importantly, power-efficient devices. As the number of IoT system devices (called things) is growing massively, there is a shift needed from the traditional LTE network to these low power networks. Power consumption should be minimum for all stages of device functionality to keep the devices working for longest possible time. We performed a power consumption analysis of CAT-M technology under various control path scenarios using a standard CAT-M modem. Due to the absence of a live CAT-M network in India, we use a network simulator to emulate live network scenario by varying network parameters. We measured the power consumed by the CAT-M modem using a standard tool and present simulation results of a variety of network configurable parameters allowed by 3GPP. These parameters are configurable both in scope of user equipment and network deployment. This paper covers some important power measurements related to Power Saving Mode (PSM), extended Discontinuous Reception Mode (eDRX), Uplink Transmission Power, Channel Repetition, Bandwidth and Sub-carrier Spacing. Data path (user payload) considerations are not scope of this document. By the end of the paper, we identified the impact of each parameter on the performance of the CAT-M modem.

The Internet of Things (IoT) is a network of devices for communicating machine to machine (M2M) based on wired and wireless Internet. IoT in agriculture is a revolutionary technology that can be applied to agricultural production year-round. The aim of this study is to summarize cases of IoT being applied to agricultural automation in the agricultural sector and to discuss the limitations and prospects for expanding the application of IoT technology in Korea. The application of IoT in agriculture was classified and analyzed based on previous data, and the sensors and communication technologies used were compared. Based on the analysis results, the limitations of and prospects for IoT in agriculture were discussed. IoT was widely used in agriculture, such as management systems, monitoring systems, control systems, and unmanned machinery. In addition, the various wireless communication technologies used in agriculture, such as Wi-Fi, long-range wide area network (LoRaWAN), mobile communication (e.g., 2G, 3G, and 4G), ZigBee, and Bluetooth, were also used in IoT-based agriculture. With the development of various communication technologies, such as 5G, it is expected that faster and broader IoT technologies will be applied to various agricultural processes in the future. IoT-based agriculture equipped with a communication system suitable for each agricultural environment can contribute to agricultural automation by increasing crop quality and production and reducing labor.

Providing ACID transactions under conflicts across globally distributed data is the Everest of transaction processing protocols. Transaction processing in this scenario is particularly costly due to the high latency of cross-continent network links, which inflates concurrency control and data replication overheads. To mitigate the problem, we introduce Ocean Vista—a novel distributed protocol that guarantees strict serializability. We observe that concurrency control and replication address different aspects of resolving the visibility of transactions, and we address both concerns using a multi-version protocol that tracks visibility using version watermarks and arrives at correct visibility decisions using efficient gossip. Gossiping the watermarks enables asynchronous transaction processing and acknowledging transaction visibility in batches in the concurrency control and replication protocols, which improves efficiency under high cross-data center network delays. In particular, Ocean Vista can access conflicting transactions in parallel and supports efficient write-quorum/read-one access using one round trip in the common case. We demonstrate experimentally in a multi-data center cloud environment that our design outperforms a leading distributed transaction processing engine (TAPIR) more than tenfold in terms of peak throughput, albeit at the cost of additional latency for gossip and a more restricted transaction model. The latency penalty is generally bounded by one wide area network (WAN) round trip time (RTT), and in the best case (i.e., under light load) our system nearly breaks even with TAPIR by committing transactions in around one WAN RTT.

WSN can be a tech in-full development with top-notch, outstanding foreseeable future. The utilization of wireless sensor network (WSN) to get a good quality observation is consists using some range of detector nodes having a network capacity which might be set up for productive effects or to get constant monitoring function. Water is critical within our own lives because of our wellbeing insurance and in different cases such as farming, marketplace, and for the animal’s presence. Diseases linked to inadequate sanitation and water states have over 200 million cases reported causing 5–10 million deaths throughout the world. Water tracking procedures are indispensable to restrain exactly the challenge is gently linked to inadequate household allocation, wasteful usage and too little decent. Wireless sensor networks also have gained fame over the study area only because they supply a promising infrastructure for both multiple monitoring and control software. For fixing the dilemma, various drinking water caliber processes were grown previously in the last ten years. The parameters included with the drinking water quality tracking would be the PH degree, turbidity, dissolved oxygen and temperature has been quantified at the true period from the detectors that ship the info into the bottom channel or control/monitoring space. This document suggests the way the tracking platform might be set up highlighting the elements of low-cost, simple setup, and effortless maintenance and handling. Using this radio platform for tracking purpose is not only going to lower the total observation procedure expenditure in the duration of centers installation and labor price tag but can even offer versatility in the duration of location or distance. In this paper, the essential layout and execution of WSN comprising Lora (wide area network) established technological innovation is suggested. The developed system is cheap and makes it possible for customization. A few preliminary links between dimension to rate the efficiency and efficiency of the machine can also be shown.

The massive increase in the Internet of Things (IoT) has brought a diverse long-range, low-power, and low bit-rate wireless network technologies. The LoRa a low-power wide area network (LPWAN) gained popularity as radio technology for the realization of many IoT applications. LoRa is typically employed together with LoRaWAN MAC protocol and operates in the license-free ISM bands. LoRa networks have an issue with scalability when the number of end nodes connected to one network is larger than the shared number of channels, that causes a collision and packets loss through receiving a wide range of different message sizes from various application. In this paper, we describe an accurate and efficient way confirmed by simulation to calculate the probability of collision rate and packet loss in LPWANs under various circumstances. Moreover, based on the LoRaWAN specification, we consider a dense network deployment of IoT devices. In the event of collisions, our proposed algorithms is classified to two approaches. Firstly a time scheduling algorithm is proposed for LoRaWAN networks that consist of devices supporting LoRaWAN class C mode for synchronization in the beginning between the gateway and the end nodes. Afterwards these devices switch to class A to significantly decrease the collision and to enhance scalability by assigning a Guard Time to each end node. Gateway acknowledgment (ACK) messages to the end nodes are used through class C. Secondly, we also propose a distance spreading factor algorithm according to the distance of the end nodes from the gateway to reduce the probability of collision. Furthermore, many of these devices are battery powered, therefore low power consumption is required.

Due to the development of the Internet and the smart end systems such as smartphones, portable laptop, and other smart mobile devices, as well as the emergence of concepts such as cloud computing, social networks, and Internet of Things, 4G and 5G have changed network requirements. A software-defined network (SDN) is a new architecture to support new network requirements. This architecture is composed of three layers, data, control, and application plane. A lot of papers have been published in well-known journals to improve network performance, so we classify the solutions for performance improvement based on three SDN layers and three SDN-based spheres which are (a) SDN-data center, (b) wireless networks, and (c) software-defined wide area network. This paper surveys the articles which have been published by Springer, IEEE, Elsevier, and ACM. We extract the performance improvement solutions and resources which are required for performance control and the metrics to evaluate the network performance. This article can help network enthusiasts to better understand, investigate, and improve the performance of SDN-based networks.

We conducted a qualitative study to get a preliminary understanding of indigents needs. The results helped us identify system requirements that led to the design of the HELPi system, a digital bracelet to enable local agencies to provide support to indigents who used roam the city. The paper aims to present the studies conducted to inform the design of our technological approach to addressing challenges related to acceptance, coverage of users, and battery lifespan. We built a prototype using LoRa™, which is a Low Power Wide Area Network (LPWAN) technology that offers several features that make it suitable for our application domain; e.g., it enables Machine-to-Machine (M2M) communications. Thus, we have taken advantage of this feature and propose a communication protocol to allow a dynamic coverage of users. We conducted assessments to determine users’ perception about its usefulness, and to measure the performance of the LoRa’s signal propagation and the battery energy consumption for the deployment of the HELPi system. According to our results, the proposed communication protocol should work with a LoRa™ Gateway in the outside setting condition and with an SNR threshold higher than − 2 dB to guarantee the successful reception of messages transmitted.

In large-scale software-defined networks (SDNs), multiple controllers are deployed. Each controller has a logically centralized vision of the network that is used to manage a set of switches. In SDN, a challenge known as controller placement problem arises which is very important to specify the number of controllers that are needed and where they should be deployed. These specifications affect the performance of the network. Meanwhile, the assignment of switches to the controllers plays key role in the quality of solution in this problem. However, recent studies focus more on simply assigning switches to their closest controllers based on propagation delay between controller and switches. In this paper, a new controller placement framework is designed which considers both control plane architecture and relation between control and data planes. This framework is considered as a multi-objective optimization model with two objective functions to minimize the flow setup time and inter-controller latency. Furthermore, we propose a new model for flow setup time function that considers all affected metrics in the placement. To solve the framework, a multi-objective algorithm called non-dominated sorting moth flame controller placement optimizer is designed. To this end, we adapt the best–worst multi-criteria decision-making method considering three metrics, namely hop count, propagation latency and link utilization, to assign switches to controllers. A heuristic approach is also used to assign a path between switch and its controller using above three metrics and path reliability. We run theses three models iteratively to find the best location for controllers, the best switch assignment to controller and also find the best route in the network. We compare our proposed framework with other models using expected path loss and link load balancing metrics. Our performance evaluations on real wide area network topologies show the efficiency of the proposed framework.

We are on the entry of the exponential advancement of the internet-of-things (IoT) due to the quick development of internet-connected smart-objects. As the number of connected smart-objects increase, IoT will continue to advance by providing connectivity and interactions between the physical and the cyber world. This connectivity is characterized by low throughput, delay sensitivity, small and wide coverage, low power consumption, low device, etc. Which explains the emergence of low power wide area network (LPWAN). LPWAN technologies are an alternative promising connectivity solutions for Internet of Things. However, the lack of an overall LPWAN knowledge that present a comprehensive analysis of LPWAN technologies is presently constraining the achievement of the modern IoT vision. In this paper, we begin with a detailed analysis of the conventional high power long-range network technologies that considers IoT applications and requirements. We further point out the need for dedicated low power wide area technologies in IoT systems. In addition, we analyse the technical specification based on the PHY and MAC layers of the technologies that are already deployed, or likely to be deployed. The focus is to incorporate both standard and proprietary technologies in our study. Furthermore, we present the modelling techniques and performance metrics that are adopted in LPWAN networks analysis. Finally, challenges and open problems are presented. The main contribution of this study is that it provides an enhanced summary of the current state-of-the-art of LPWAN suitable to meet the requirements of IoT, while uniquely providing LPWAN’s modelling techniques, performance metrics and their associated enablers.

A generalized Chinese Remainder Theorem (GCRT)-based multi-secret sharing (MSS) scheme, which can solve a tricky problem that the correspondences between multi-secret and their remainders in each share are unclear, has been proposed recently. But potential security issues should be taken into accounts in the design and implementation of MSS. To protect long-lived multi-secret against intended attacks, in this paper, we propose a proactive multi-secret sharing (PMSS) scheme. It consists of share generation, share refreshing, and secret recovery phases. Compared with those existing MSS schemes, unordered shares in the proposed PMSS scheme are refreshed at a fixed period while the multi-secret remains intact. This can lead to a higher security level because an adversary must capture at least t shares from total n shares during a period to crack the secrets. Both the share generation and refreshing phases can be easily realized by using modular operation. What is more, the proposed PMSS scheme has a much less computational load thanks to the use of a lightweight GCRT-based algorithm in the secret recovery phase. Finally, some examples are provided to illustrate the efficiency, and some analyses regarding security are also given.

Client-side metadata prefetching is commonly used in wide area network (WAN) file systems because it can effectively hide network latency. However, most existing prefetching approaches do not meet the various prefetching requirements of multiple workloads. They are usually optimized for only one specific workload and have no or harmful effects on other workloads. In this paper, we present a new self-tuning client-side metadata prefetching scheme that uses two different prefetching strategies and dynamically adapts to workload changes. It uses a directory-directed prefetching strategy to prefetch the related file metadata in the same directory, and a correlation-directed prefetching strategy to prefetch the related file metadata accessed across directories. A novel self-tuning mechanism is proposed to efficiently convert the prefetching strategy between directory-directed and correlation-directed prefetching. Experimental results using real system traces show that the hit ratio of the client-side cache can be significantly improved by our self-tuning client-side prefetching. With regards to the multi-workload concurrency scenario, our approach improves the hit ratios for the no-prefetching, directory-directed prefetching, variant probability graph algorithm, variant apriori algorithm, and variant semantic distance algorithm by up to 15.22%, 6.32%, 10.08%, 11.65%, and 10.73%, corresponding to 25.24%, 18.11%, 23.53%, 24.94%, and 24.19% reductions in the average access time, respectively.

Computational offloading happens to be a prominent solution for leveraging the performance of handheld devices. It raises the feasibility of executing computation-intensive and latency-conscious tasks with the help of task migration to proximate cloud servers. However, longer Wide Area Network latencies of cloud and greater mobile data consumption paved the way to adopting opportunistic offloading instead of remote offloading. This proposed work uses an edge-based solution of Fog computing to handle such tasks and to provide the users with a high Quality of Experience. This paper presents a Capability-Aware Supply Chain Management Model (CASCM $$^2$$ ) as an extension of traditional Supply Chain Management (SCM) model. CASCM $$^2$$ dynamically selects a crowd of competent mobile devices within a Foglet that is in proximity to the users and offloads the complex computational tasks to them. The proposed model aims at optimizing two parameters, such as communication overhead and conductance cost, as they possess a remarkable impact on offloading delay-sensitive tasks. Hence an overall objective optimization is achieved using a dual Lagrangian decomposition method, which subdivides and solves the optimization of parameters in parallel. Experimental analysis of the participator selection is performed for a single period as well as multiple periods. The performance results yield a considerable contribution that alleviates the issues in delay-sensitive applications deployed in the Fog framework.

This research presents a multi-band hybrid mobile phone antenna based on electromagnetic coupling, which can be applied to mobile handheld devices, occupying a small board space of 39.7mm×15.6mm on the system circuit board. By adding resonant and coupled branch instead of multi-feed on the traditional bent antenna, this design provides four wide operating bands of 0.772—0.998 GHz, 1.540—1.600 GHz, 1.680—2.270 GHz and 2.300—2.690 GHz with the hybrid feature of planar inverted-F antenna (PIFA), L-shape, U-shape and S-shape structures, which cover nine-band, i.e., GSM850, GSM900, GPS1575, DCS1800, PCS1900, IMT200, LTE2300, LTE2600 and Blue Tooth/Wi-Fi. Ansoft software HFSS is used in this research to make the antenna performance better and the operating principle of the proposed antenna is described in detail. Result of simulation reveals that the maximum gains of these four wide bands are 2.20, −0.99, 4.01 and 4.05 dBi, respectively. Moreover, this research also tests the return loss (S11) of the fabricated antenna with the vector network analyzer and the result is in accordance with the simulation result on the whole. There are four wide resonant frequencies which cover nine-band of wireless wide area network (WWAN), wireless local area network (WLAN) and long term evolution (LTE), when the available bandwidth is better than 6 dBi return loss.

Low-power, long-range wireless communication has become important for IoT applications in wide space. A Low-Power Wide Area Network (LPWAN) has been proposed to support wireless communication. It provides very long communication distances with low data rates and uses a very simple transmission mechanism to deliver data packets over long distances. The simple transmission mechanism does not consider device characteristics according to generated data. If priority according to the device characteristics is considered during data transmission, the transmission efficiency of each service can be improved. Therefore, this paper proposes data transmission considering device characteristics. The proposed method employs a k-means clustering algorithm to classify devices according to the traffic characteristic. Each group of classified devices has different priority, and the wireless channel access time is determined by that priority. Using different channel access times according to priority allows end-devices to avoid collisions and improve transmission efficiency in LPWAN with long delay. The proposed method is compared to typical transmission methods in an LPWAN through the performance evaluation by computer simulations and its transmission efficiency is validated.

A smart meter neighborhood area network is usually regarded as the last mile network, which plays a significant role for communications in smart grid. A neighborhood area network typically consists of smart meters and Data Aggregation Points (DAPs), which collect energy consumption or billing information from smart meters and forward the information to wide area network gateways via wireless communications. The location of DAPs significantly affects the distance and associated transmission routes between DAPs and smart meters. In this paper, we investigate the DAP placement problem and propose solutions to reduce the distance between DAPs and smart meters. Specifically, the DAP placement problem is formulated with two objectives, e.g., the average distance minimization and the maximum distance minimization. The concept of network partition is introduced in this paper and two associated algorithms are developed to address the DAP placement problem. Extensive simulations are conducted based on a real suburban neighborhood topology. The simulation results verify that the proposed solutions are able to remarkably reduce the communication distance between DAPs and their associated smart meters.

Long lifetime of a wireless sensor/actuator node, low transceiver chip cost and large coverage area are the main characteristics of the low power wide area network (LPWAN) technologies. These targets correlate well with the requirements imposed by the health and wellbeing applications of the digital age. Therefore, LPWANs can found their niche among traditional short range technologies for wireless body area networks, such as ZigBee, Bluetooth and ultra wideband. To check this hypothesis, in this work we investigate the indoor performance with one of the LPWAN technologies, named LoRa, by the means of empirical measurements. The measurements were conducted using the commercially available devices in the main campus of the University of Oulu, Finland. In order to obtain the comprehensive picture, the experiments were executed for the sensor nodes operating with various physical layer settings, i.e., using the different spreading factors, bandwidths and transmit powers. The obtained results indicate that with the largest spreading factor of 12 and 14 dBm transmit power, the whole campus area (570 m North to South and over 320 m East to West) can be covered by a single base station. The average measured packet success delivery ratio for this case was 96.7%, even with no acknowledgements and retransmissions used. The campus was covered also with lower spreading factors with 2 dBm transmit power, but considerably more packets were lost. For example with spreading factor 8, 13.1% of the transmitted packets were lost. Aside of this, we have investigated the power consumption of the LoRa compliant transceiver with different physical layer settings. The experiments conducted using the specially designed module show that based on the settings used, the amount of energy for sending the same amount of data may differ up to 200-fold. This calls for efficient selection of the communication mode to be used by the energy restricted devices and emphasizes the importance of enabling adaptive data rate control.

In this paper, a supervisory computer network for Borneo-Wide Power Grid system have been proposed and implemented, which includes a renewable power generation and advanced metering infrastructure. An Internet-based communication network running on multi-protocol label switching (MPLS) has been implemented for a smart power grid, with the addition of the renewable energy monitoring system. The centralized supervisory control and data acquisition systems (SCADA) are replaced by a wide area monitoring system(WAMS) comprising of a phasor measurement unit (PMU). The implemented communication network used advanced metering infrastructure that operates on worldwide interoperability for microwave access (WiMAX), wireless fidelity (Wi-Fi) and low power Wi-Fi, which are proposed for the distribution systems of Sarawak Energy. The proposed wide area network (WAN) is simulated using OPNET Modeler and the results are compared with the existing WAN used by Sarawak Energy.

Live virtual machine migration is one of the most promising features of data center virtualization technology. Numerous strategies have been proposed for live migration of virtual machines on local area networks. These strategies work perfectly in their respective domains with negligible downtime. However, these techniques are not suitable to handle live migration over wide area networks and results in significant downtime. In this paper we have proposed a Machine Learning based Downtime Optimization (MLDO) approach which is an adaptive live migration approach based on predictive mechanisms that reduces downtime during live migration over wide area networks for standard workloads. The main contribution of our work is to employ machine learning methods to reduce downtime. Machine learning methods are also used to introduce automated learning into the predictive model and adaptive threshold levels. We compare our proposed approach with existing strategies in terms of downtime observed during the migration process and have observed improvements in downtime of up to 15 %.

The communication network of a Smart Grid has a three-level hierarchical structure consisting of Home Area Network (HAN), Neighborhood Area Network (NAN) and Wide Area Network (WAN). Wireless communication, due to its advantages, is identified as a potential candidate for Smart Grid communications, especially in HAN and NAN. However, wireless transmission is inherently unreliable, whereas communication reliability is one of the fundamental requirements of Smart Grid applications. In this paper, a two-layer communication model based on IEEE reference grids is considered for NAN and a method based on transmission redundancy is proposed to improve the reliability of wireless communications in NAN, while the communication delay requirement of the Smart Grid is considered as a restriction. The proposed method finds the optimum number of transmissions at each hop with respect to the loss probability and total delay constraints. Comparing the proposed method to the case of an equal number of transmissions for all the hops, it is shown by analysis that the proposed method achieves a superior reliability while meeting the delay requirement. In addition, the simulation-based evaluation of the proposed method supports the validity of the results obtained from the analytical model.

The paper focuses on cooperation between cloud and network operators, as well as on fitting particular routing strategies to various cloud services. Three cooperation models are presented, analyzed and compared in the paper: the proposed model and two widely used reference models. The main difference between the models is the set of information being exchanged between the involved parties. Additionally, we analyze the applicability of four fitting schemas for each considered model. It is shown that the proposed model, alongside with an appropriate fitting schema, is able to reduce the blocking probability of cloud services requests. At the same time, thanks to the use of green anycast strategies, it is able to significantly reduce carbon dioxide emission.

Smart Grids are characterized by the application of information communication technology (ICT) to solve electrical energy challenges. Electric power networks span large geographical areas, thus a necessary component of many Smart Grid applications is a wide area network (WAN). For the Smart Grid to be successful, utilities must be confident that the communications infrastructure is secure. This paper describes how a WAN can be deployed using WiMAX radio technology to provide high bandwidth communications to areas not commonly served by utility communications, such as generators embedded in the distribution network. A planning exercise is described, using Northern Ireland as a case study. The suitability of the technology for real-time applications is assessed using experimentally obtained latency data.

Real-time interactive multimedia communications are becoming increasingly useful for education, business, e-commerce and e-government, providing an enriched user experience in teleconferencing, e-meetings, distance training and product demonstrations. Large corporations are usually located at several sites, so real-time multipoint sessions within corporations are especially difficult. IP multicast is available or feasible within each site of an organization. Thus, corporate networks can be considered as various multicast-capable networks interconnected through a wide area network without multicast connectivity. This paper proposes a resilient self-managed overlay network to support real-time multipoint interactive sessions within corporate networks. The proposed overlay takes advantage of the configuration of corporate networks to self-organize and provide an efficient media delivery service, making use of multicast communications wherever available. Various self-healing techniques are implemented allowing for the continuity of ongoing sessions in spite of network disruptions and entity failures. Extensive simulations and tests have been carried out to assess the performance and resilience of the overlay facing several types of disruptions.

This paper presents the results and experiences of adapting and improving the Many-Task Computing (MTC) framework Kestrel for use with bag of tasks applications and the STAR experiment in particular. Kestrel is a lightweight, highly available job scheduling framework for Virtual Organization Clusters (VOCs) constructed in the cloud. Kestrel uses the Extensible Message and Presence Protocol (XMPP) for increasing MTC platform scalability and mitigating faults in Wide Area Network (WAN) communications. Kestrel's architecture is based upon pilot job frameworks used extensively in Grid computing, with fault-tolerant communications inspired by command-and-control botnets. The extensibility of XMPP has allowed development of protocols for identifying manager nodes, discovering the capabilities of worker agents, and for distributing tasks. Presence notifications provided by XMPP allow Kestrel to monitor the global state of the pool and to perform task dispatching based on worker availability. Since its inception, Kestrel has been modified based on its performance managing operational scientific workloads from the STAR group at Brookhaven National Laboratories. STAR provided a virtual machine image with applications for simulating proton collisions using PYTHIA and GEANT3. A Kestrel-based Virtual Organization Cluster, created on top of Clemson University's Palmetto cluster, CERN, and Amazon EC2, was able to provide over 400,000 CPU hours of computation over the course of a month using an average of 800 virtual machine instances every day, generating nearly seven terabytes of data and the largest PYTHIA production run that STAR has achieved to date.

The focus of this paper is on the design of the so-called Optical Wide Area Networks (owans), i.e., optical networks that cover broad areas. Our objective is to investigate efficient owan network design, where demand provisioning takes full advantage of the nodal switching equipment and of the network interface platforms under asymmetric traffic. It involves granting all traffic requests while minimizing the network capital and operational expenses, throughout an optimal dimensioning of the nodal equipment, i.e., minimizing the number and the location of the network nodal equipment. The originality of our work is in the forethought and the investigation of these issues. We establish a mathematical model which makes use of large scale optimization tools and propose a column generation algorithm coupled with a rounding off heuristic in order to solve it efficiently. In our experiments, with different network and traffic instances, we show that a careful dimensioning and location of the nodal equipment can save up to 35% of capital expenses, and even more sometimes.

The purpose of tele-immersive collaboration is to enable people in separate locations to work together effectively by the Virtual Reality (VR) technology facilitating the human intuitive insight and interpretation. Consequently, it is important to cogitate with figures and characters as well as voice communication in Collaborative Virtual Environment (CVE). In this paper, we constructed tele-immersive CVE with annotation capability and free-hand drawing of characters and figures into Immersive Projection Technology (IPT) environment. In addition, participants from remote sites connected over a Wide Area Network (WAN) were enabled to interact with each other by sharing annotations via a PDA application. Moreover, we developed applications for scientific visualization and, for intellectual work based on KJ Method inside a tele-immersive CVE. From these results, we are able to maintain essential information for thinking by making annotation on IPT environment, and have proved the system can support intuitive understanding in remote collaborative work.

Several MPI systems for Grid environment, in which clusters are connected by wide-area networks, have been proposed. However, the algorithms of collective communication in such MPI systems assume relatively low bandwidth wide-area networks, and they are not designed for the fast wide-area networks that are becoming available. On the other hand, for cluster MPI systems, a bcast algorithm by van de Geijn, et al. and an allreduce algorithm by Rabenseifner have been proposed, which are efficient in a high bi-section bandwidth environment. We modify those algorithms so as to effectively utilize fast wide-area inter-cluster networks and to control the number of nodes which can transfer data simultaneously through wide-area networks to avoid congestion. We confirmed the effectiveness of the modified algorithms by experiments using a 10 Gbps emulated WAN environment. The environment consists of two clusters, where each cluster consists of nodes with 1 Gbps Ethernet links and a switch with a 10 Gbps upper link. The two clusters are connected through a 10 Gbps WAN emulator which can insert latency. In a 10 millisecond latency environment, when the message size is 32 MB, the proposed bcast and allreduce are 1.6 and 3.2 times faster, respectively, than the algorithms used in existing MPI systems for Grid environment.

In recent years, Grid technologies have been standardized based on Web service specifications. Of these specifications, the WS-Resources Framework and WS-Notification have attracted a great deal of attention. This paper focuses on scientific applications integration on the wide area network. We propose and implement a new distributed workflow management system called the “Application Igniting System.” This system is based on the publish-subscribe notification defined by the WS-Notification specification and realizes a flexible and loosely coupled workflow control by introducing some Web services, which handle message exchange. By applying to a typical bioinformatics workflow, we concluded that the overhead time related to message exchange is very short.

Data access latency is an important metric of system performance in data grid. By means of efficient replication strategy, the amount of data transferred in a wide area network will decrease, and the average access latency of data will decrease ultimately. The motivation of our research is to solve the optimized replica distribution problem in a data grid; that is, the system should utilize many replicas for every data with storage constraints to minimize the average access latency of data. This paper proposes a model of replication strategy in federated data grid and gives the optimized solution. The analysis results and simulation results show that the optimized replication strategy proposed in this paper is superior to LRU caching strategy, uniform replication strategy, proportional replication strategy and square root replication strategy in terms of wide area network bandwidth requirement and in the average access latency of data.

In all optical backbone networks, the introduction of Ultra Long Haul (ulh) optical systems associated with Optical Add Drop Multiplexers (oadm) gives rise to new network architectures and also to new engineering constraints, because signals suffer effects which do not exist in networks today. The purpose of this paper is to study, through numerical simulations, the impact on the signal brought by the concatenation of oadms. It is usually predicted that the transmission quality is severely degraded by filtering effects. However, the simulations show that by introducing for example a small amount of non-linearities, degradations do not obligatorily happen.

This paper explores the issues of measurement and comparison of the current state of advanced manufacturing technology (AMT) adoption in India, including important information technology (IT) factors, and, surprisingly, this appears to be the first such attempt. For a worldwide perspective, comparison is made between Indian firms, firms in a developed country (Canada), and in a developing country (China). Contrary to expectation, the average score of AMT adoption degree of Indian companies in our survey is higher than that of all Canadian companies (when unadjusted for size) and of Chinese companies in one of the highly industrialized regions of China as measured in other surveys. While this suggests considerable strength of the Indian manufacturing sector, there should be further evaluation by other studies in this area to refine and develop these results. This study finds the top six AMTs currently adopted in India are plant certification, computer aided design, local area network, quality circle, MRP/ERP, and wide area network. Clearly four of these top six are directly in the IT area (CAD, LAN, WAN) or directly dependent on it (MRP/ERP systems), indicating a strong IT adoption rate as well as its underlying supportive role in the overall AMT adoption in India. The comparison between Indian firms and Canadian firms indicates that Indian firms adopted computer networks less and MRP/ERP and rapid prototyping systems more. Tests in our survey also reinforce the hypothesis that larger companies are more likely to adopt AMT than the smaller ones.

There have been parallel technological developments in wireless local network (WLAN) and cellular wide area network (WAN) technologies. This is evidenced by the boom in fast WLANs enabled devices, the spread of 2.5 G networks and the increasing emergence 3 G communication networks, applications and terminals. The prospects of integrating WLAN and cellular WAN technologies with support for seamless handoffs between the two heterogeneous have changed the mentality of researchers from considering WLAN technology as a threat to the future of wide area cellular networks to accepting the technology as a complementary solution. A number of architectures for interworking the two different network types have been proposed mainly based on the loose coupling interworking approach recommended by the ETSI. One of the main weaknesses anticipated with loose coupling architecture is excessive handoff latency, which may lead to data loss, traffic congestion and handoff failure. In this paper an architecture for interworking WLAN and the GPRS networks, based on the ETSI tight coupling approach, is proposed.

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.

Module-intensive user-interactive technology towards developing Internet-based communication has become instrumental in implementing actuation sequences of a remotely located mechatronic device. Bi-directional data communication metrics, hitherto dominated largely by text-based formats, has attained substantial up-gradation whereby global access vis-a-vis exchange of technical data has become a boon for the Internet users at large. However, presence of a common web-server in the communication loop has been indispensable till date. The present work reports a novel technique, whereby the web-server is bypassed and the web-enability is ensured by means of peer-to-peer socket communication between the client and the host in situ. The paper delineates algorithm of a new protocol and developmental semantics of the end-hardware for web-enabled communication in order to successfully orchestrate various domains of traditional client---server handshaking in a meaningful and synergistic manner. The developed protocol encompasses programming semantics of web-enabled applets, formulation logistics and portability issues over the Internet. The paper presents the real-life testing sequences for remote activation of a table-top robotic manipulator successively in a Local Area Network (LAN) and also in a Wide Area Network (WAN) and finally through the Internet, using a dedicated web-site.

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.

The continual improvement in computer performance together with the prevalence of high-speed network connections having high throughput and moderate latencies enables the deployment of multimedia applications, such as collaborative virtual environments, over wide area networks (WANs). These applications can serve as simulated environments in scenarios such as emergency response training to catastrophic disasters, military training, and entertainment. Many of these systems use 3D graphics for display and may be required to distribute geometric models on demand between participants. Progressive meshes provide an attractive mechanism for such distribution. Previous uses of progressive meshes have sent data using reliable protocols (TCP). However, such protocols have disadvantages in on-demand settings, in that they: (1) use flow control, which limits performance in WANs; (2) add additional bandwidth when there is loss; (3) treat all loss as an indication of congestion; and (4) require feature-rich multicast support, which is not always available. In this paper, we modify progressive mesh models to allow reconstruction even in the event of packet loss. We use these modifications in two transmission schemes, a hybrid transmission that uses TCP and UDP to send packets and a forward error correction transmission scheme that uses redundancy to decode the information sent. We assess the performance of these transmission schemes when deployed on network testbeds that simulate wide area and wireless characteristics.

This paper introduces an RTP-packets' loss recovery scheme in MPEG-4 playback type multicast application model, which is based on retransmission scheme. Through the auxiliary and coordinated buffer playing scheme of layered “buffer-routers”, the RTP-packets' loss recovery in limited time is made possible. We consider in the scheme to handle retransmission request with buffer waiting when network congestion occurs. Thus, neither the degree of congestion will be worsened nor the retransmission request will be lost when sending the request to higher-level buffer router. The RTP-packets' loss recovery scheme suggested by us is not only applied to MPEG-4 multicast application in LAN, but also can be extended to more spacious WAN (wide area network) when user groups comparatively centralize in certain number of local areas.

The rapid increase of World Wide Web users and the development of services with high bandwidth requirements have caused the substantial increase of response times for users on the Internet. Web latency would be significantly reduced, if browser, proxy or Web server software could make predictions about the pages that a user is most likely to request next, while the user is viewing the current page, and prefetch their content. In this paper we study Predictive Prefetching on a totally new Web system architecture. This is a system that provides two levels of caching before information reaches the clients. This work analyses prefetching on a Wide Area Network with the above mentioned characteristics. We first provide a structured overview of predictive prefetching and show its wide applicability to various computer systems. The WAN that we refer to is the GRNET academic network in Greece. We rely on log files collected at the network's Transparent cache (primary caching point), located at GRNET's edge connection to the Internet. We present the parameters that are most important for prefetching on GRNET's architecture and provide preliminary results of an experimental study, quantifying the benefits of prefetching on the WAN. Our experimental study includes the evaluation of two prediction algorithms: an “n most popular document” algorithm and a variation of the PPM (Prediction by Partial Matching) prediction algorithm. Our analysis clearly shows that Predictive prefetching can improve Web response times inside the GRNET WAN without substantial increase in network traffic due to prefetching.

Optical fiber has evolved from a not-so-transparent glass tube to an extraordinarily efficient transmission medium. It is now acknowledged as a central element of modern telecommunication being part of the whole optimization process to further improve transmission system performance and cost. In this paper, we briefly introduce transmission system optimization problematics as well as key fiber characteristics. We then review the elements of fiber design for optimized optical communication networks, including metropolitan, long and ultra-long haul applications and show how fibers have evolved over the last ten years to keep pace with more and more demanding requirement of transmission system.

This paper aims at looking beyond the gloomy current market evolution of the optical industry. Based on an analysis of the telecom transport market evolution (metropolitan as well as backbone), taking benefit of very significant technological breakthroughs in optics in recent years, this paper will suggest promising, yet pragmatic applications in telecom transport networks where optics will play a significant role beyond pure optical transmission.

On the basis of Europeanist project results in the field of photonics, theoptimist thematic network has produced a roadmap for optical communications. This work is described in the present article which provides scenarios for the evolution of the optical network in the coming 10 years. Predictable developments in optical components, sub-systems and systems and their consequences on the architecture and performances of the networks are analysed. Specific interest is focused on the various parts of the network structure namely the access, the metropolitan area, the wide area and the global networks. Technical documents elaborated by theoptimist consortium and minutes fromist workshops can be found on the website http://www.ist-optimist.org/.[1]. They constitute a main source for further information.

The computational Grid is currently gaining in popularity, and it enables computers scattered all over the world to be connected by the Internet as if they are part of a large computational infrastructure. While the computational Grid gathers more and more computational resources and the number of the applications for the computational Grid is increasing, load balancing for the computational Grid is still not effective enough. Because the computers are connected by a wide area network on the computational Grid, the significant communication latency and the frequency of large wave throughputs make it difficult to achieve effective load balancing. Thus, in this paper, we propose an algorithm to predict networking loads on the computational Grid to make the use of computational resources more efficient. The proposed algorithm based on the Markov model is evaluated using an actual networking load. As a result, the Markov model based algorithm offers the most accurate predictions compared with the related work.

We consider the problem of routing in a wide area mobile ad hoc network called Terminode Network. Routing in this network is designed with the following objectives. First, it should scale well in terms of the number of nodes and geographical coverage; second, routing should have scalable mechanisms that cope with the dynamicity in the network due to mobility; and third, nodes need to be highly collaborative and redundant, but, most of all, cannot use complex algorithms or protocols. Our routing scheme is a combination of two protocols called Terminode Local Routing (TLR) and Terminode Remote Routing (TRR). TLR is used to route packets to close destinations. TRR is used to route to remote destinations. The combination of TLR and TRR has the following features: (1) it is highly scalable because every node relies only on itself and a small number of other nodes for packet forwarding; (2) it acts and reacts well to the dynamicity of the network because as a rule multipath routing is considered; and (3) it can be implemented and run in very simple devices because the algorithms and protocols are very simple and based on high collaboration. We performed simulations of the TLR and TRR protocols using the GloMoSim simulator. The simulation results for a large, highly mobile ad hoc environment demonstrate benefits of the combination of TLR and TRR over an existing protocol that uses geographical information for packet forwarding.

A secure reliable multicast protocol enables a process to send a message to a group of recipients such that all honest destinations receive the same message, despite the malicious efforts of fewer than a third of them, including the sender. This has been shown to be a useful tool in building secure distributed services, albeit with a cost that typically grows linearly with the size of the system. For very large networks, for which such a cost may be too prohibitive, we present two approaches for bringing the cost down: First, we show a protocol whose cost is on the order of the number of tolerated failures. Secondly, we show how relaxing the consistency requirement to a selected probability level of guarantee can bring down the associated cost to a constant.

Operators of multi?service networks require simple charging schemes with which they can fairly recover costs from their users and effectively allocate network resources. This paper studies an approach for computing such charges from simple measurements (time and volume), and relating these to bounds of the effective bandwidth. To achieve economic efficiency, it is necessary that usage?based charging schemes capture the relative amount of resources used by connections. Based on this criteria, we evaluate our approach for real traffic consisting of Internet Wide Area Network traces and MPEG?1 compressed video. Its incentive compatibility is shown with an example involving deterministic multiplexing, and the effect of pricing on a network's equilibrium is investigated for deterministic and statistical multiplexing. Finally, we investigate the incentives for traffic shaping provided by the approach.

Digital libraries involve various types of data like text, audio, images and video. The data objects are typically very large and of the order of hundreds and thousands of kilobytes. In a digital library, these data objects are distributed in a wide area network. Retrieving large data objects in a wide area network has a high response time. We have conducted experiments to measure the communication overhead in the response time. We have studied the correlation between communication and size of data, between communication and type of data and the communication delay to various sites in a local and wide area network. We present different strategies for reducing delay while communicating multimedia data. Images are amenable to losing data without losing semantics of the image. Lossy compression techniques reduce the quality of the image and reduce the size leading to a lower communication delay. We compared the communication delay between compressed and uncompressed images and study the overhead due to compression and decompression. We present issues in providing digital library service to mobile users and discuss a question: What if communication were free? Finally, we present a framework for efficient communication of digital library data.

LandStar is a differential global positioning service (DGPS) that provides 24-h real-time positioning for various applications on land, water, and air in North America, Australia, New Zealand, Europe, and Africa. Its focus is on real-time applications requiring a submeter positioning capability such as agriculture, forestry, Geospatial Information Systems (GIS), survey/mapping, and land/vehicular navigation. LandStar uses a Wide Area Network of reference stations to derive DGPS corrections to model the variation of GPS error sources over a large area. These model parameters are used by the Virtual Reference Station processors to calculate standard corrections that are available for all predefined locations in the network. The corrections are transmitted to the user by L-band satellite communication in the standard RTCM SC104 DGPS correction format. This article investigates the performance of the LandStar Mk III system under various operational conditions and assesses its performance in both static and kinematic modes. Four field tests were conducted during 12 months that tested the sysem in clear static and kinematic conditions as well as suboptimal environments associated with low and heavy foliage conditions. Both the accuracy and availability of the system under these conditions is investigated, with an emphasis on whether the above variables are caused by the LandStar system differential corrections, the GPS measurements, or a combination of both. © 1999 John Wiley & Sons, Inc.

It is an unfortunate fact that current general-purpose middleware implementations cannot support large-scale, wide-area, real-time, high-throughput applications using distributed objects. This paper discusses the background to middleware and explores the need for research into techniques that support high-capacity implementations In order to place the role of this work in context, an overview is given of the simple applications-middleware-infrastructure three-layered model that has been adopted. The paper also gives some background on how applications may specify the non-functional characteristics that they demand of supporting middleware, including invocation latency, which is a widely recognised, measured and reported metric, and invocation throughput rate, which is not. The paper establishes that there is a growing demand for high-invocation-throughput applications, such as the World Wide Web (WWW), collaborative virtual reality (CVR) and intelligent networks (INs), and also that there is increasing availability of suitable high-capacity infrastructure including networks, hosts and operating systems. It also examines the reasons for a lack of implemented high-capacity capacity middleware and reviews current directions in distributed object (DO) research. There is insufficient but growing activity in high-throughput techniques, such as weak-consistency approaches to object replication, that would enable applications to take advantage of high-capacity infrastructure.