Virtual Bandwidth Research Articles

Load adaptive merging algorithm for multi-tenant PON environments

Wavelength division multiplexing\ ime division multiplexing passive optical network (WDM/TDM-PON) is the attractive candidate for PON bandwidth sharing among multiple service providers, featuring massive bandwidth and longer reach. This infrastructure reduces the overall cost of the Fiber-to-the-premises (FTTP) services and offers relatively lower tariffs for the end customers. The dynamic bandwidth and wavelength allocation (DBWA) process in such PON networks ensure the fair sharing of the available bandwidth resources among the virtual network operators (vNOs). The earlier reported DBWA schemes with multiple vNOs have not efficiently utilized the unused and residual upstream bandwidth. This study presents a novel load adaptive merging algorithm (LAMA) for converting various individual virtual bandwidth maps(vBWmaps) into a single physical bandwidth map (phyBWMap). The LAMA scheme modifies the existing strict priority scheme called the Priority-Based Merging Algorithm (PBMA) scheme and improves the performance of the merging engine by allocating the phyBWMap in a load adaptive manner to the vNOs in the multi-tenant PON architecture. The proposed algorithm is compared with PBMA in terms of throughput efficiency, upstream delay, and capacity utilization under self-similar and Poison traffic scenarios. The results show that the proposed scheme offers higher bandwidth utilization resulting in increased throughput with lower upstream delays in the multi-tenant PON environment.

Design of Sparse Multiband Signal for Precise Positioning With Joint Low-Complexity Time Delay and Carrier Phase Estimation

This paper presents a methodology to design a sparse multiband ranging signal with a large virtual bandwidth, from which time delay and carrier phase are estimated by a low complexity multivariate maximum likelihood (ML) method. In the estimation model for a multipath channel, not all reflected paths are considered, and time delay and carrier phase are estimated in a step-wise manner to further reduce the computational load. By introducing a measure of dependence and a measure of bias for a multipath reflection, we analyse the bias, precision and accuracy of time delay and carrier phase estimation. Since these two indicators are determined by the signal spectrum pattern, they are used to formulate an optimization for signal design. By solving the optimization problem, only a few bands from the available signal spectrum are selected for ranging. Consequently, the designed signal only occupies a small amount of signal spectrum but has a large virtual bandwidth and can thereby still offer a high ranging precision with only a small bias, based on the low-complexity simplified ML method. Numerical and laboratory experiments are carried out to evaluate the ranging performance of the proposed estimation method based on sparsely selected signal bands. Relative positioning, in which we only measure a change in position, based on either the time delay estimates or the carrier phase estimates, is presented as a proof-of-concept for precise positioning. The results show that positioning based on only 7 out of 16 signal bands, sparsely placed in the available spectrum, achieves a decimeter level accuracy when using time delay estimates, and a millimeter level accuracy when using carrier phase estimates. Compared with the case of using all available bands, and without largely decreasing the positioning performance, the computational complexity when using the sparse multiband signal can be reduced by about 80%.

High-Accuracy Narrowband Software-Defined Radar Using Successive Multiple-Frequency Continuous-Wave Modulation for Sensing Applications

This paper describes a software-defined radar sensor based on successive multiple-frequency continuous-wave (S-MFCW) modulation. S-MFCW is a radar modulation technique capable of detecting static and moving targets with high accuracy while modulating the transmitted signal over a narrow frequency bandwidth. The proposed software-defined radar is implemented as a highly reconfigurable system made of a field-programmable gate array (FPGA)-based system-on-chip (SoC), a wideband homodyne radio frequency (RF) transceiver, and two antennas. The utilized programmable general-purpose SoC and transceiver front end allow for some of the radar components to be reconfigured by a software program running on the SoC. This radar system adequately follows the software-defined radar paradigm wherein most of the radar operation is configured and controlled using software programs, thus providing the ability to combine multiple radar functions on the same hardware resource. The presented radar sensor is experimentally evaluated in both outdoor and indoor measurement scenarios. The radar operates in the S-band and occupies a narrow virtual bandwidth of 34 MHz when transmitting S-MFCW tones whose frequencies are shifted by two gaps of 4 and 30 MHz, from 3.550 to 3.584 GHz. Experimental results show that the proposed radar system is capable of measuring short-range targets with a range accuracy of less than 21 cm.

Design of Onboard Real-Time Networks Based on SDN Technology

Modern onboard equipment complexes (OEC) utilize AFDX and FC-AE-ASM-RT switched networks implementing a virtual link-based approach to real-time data transfer. The main drawback of these networks is their limited or absent support for dynamic reconfiguration of virtual links, which makes impossible the dynamical recomposition of OEC operation modes, particularly in case of multiple equipment failures. To remove these drawbacks, in this paper an approach is proposed to use software-defined networks (SDN) as onboard real-time networks. The proposed approach is based on implementation of a virtual link-based technology (similar to those used in AFDX and FC-AE-ASMRT) in an SDN supporting OpenFlow 1.3 protocol. The approach was implemented as a functional prototype and experimentally evaluated in a virtual network environment based on Ofsoftswitch13 software SDN switches and RUNOS controller. The experiments indicated that the proposed data exchange scheme allows the transfer of messages within the given limits on delay and jitter, and does not allow violation of constraints on a virtual link bandwidth. The experiments also confirmed that dynamic reconfiguration of virtual links in SDN does not interrupt the data transfer through unchanged virtual links. An important direction for future work is development of algorithms for dynamic creation of virtual link routes in course of OEC reconfiguration. The final goal of the work is to create an SDN-based network technology supporting both real-time data transfer and automatic network reconfiguration in case of OEC mode change, including parrying multiple failures.

A novel virtual disk bandwidth allocation framework for data-intensive applications in cloud environments

Recently, cloud computing has become a promising distributed processing paradigm to deploy various kinds of non-trivial applications. In those applications, most of them are considered data-intensive and therefore require the cloud system to provide massive storage space as well as desirable I/O performance. As a result, virtual disk technique has been widely applied in many real-world platforms to meet the requirements of these applications. Therefore, how to efficiently allocate the virtual disk bandwidth has become an important issue that needs to be addressed. In this paper, we present a novel virtual disk bandwidth allocation framework, in which a set of virtual bandwidth brokers are introduced to make allocation decisions by playing two game models. Theoretical analysis and solution are presented to prove the effectiveness of the proposed game models. Extensive experiments are conducted on a real-world cloud platform, and the results indicate that the proposed framework can significantly improve the utilisation of virtual disk bandwidth comparing with other existing approaches.

A novel virtual disk bandwidth allocation framework for data-intensive applications in cloud environments

A novel virtual disk bandwidth allocation framework for data-intensive applications in cloud environments

Data-Aware Scheduling Strategy for Scientific Workflow Applications in IaaS Cloud Computing

Scientific workflows benefit from the cloud computing paradigm, which offers access to virtual resources provisioned on pay-as-you-go and on-demand basis. Minimizing resources costs to meet user’s budget is very important in a cloud environment. Several optimization approaches have been proposed to improve the performance and the cost of data-intensive scientific Workflow Scheduling (DiSWS) in cloud computing. However, in the literature, the majority of the DiSWS approaches focused on the use of heuristic and metaheuristic as an optimization method. Furthermore, the tasks hierarchy in data-intensive scientific workflows has not been extensively explored in the current literature. Specifically, in this paper, a data-intensive scientific workflow is represented as a hierarchy, which specifies hierarchical relations between workflow tasks, and an approach for data-intensive workflow scheduling applications is proposed. In this approach, first, the datasets and workflow tasks are modeled as a conditional probability matrix (CPM). Second, several data transformation and hierarchical clustering are applied to the CPM structure to determine the minimum number of virtual machines needed for the workflow execution. In this approach, the hierarchical clustering is done with respect to the budget imposed by the user. After data transformation and hierarchical clustering, the amount of data transmitted between clusters can be reduced, which can improve cost and makespan of the workflow by optimizing the use of virtual resources and network bandwidth. The performance and cost are analyzed using an extension of Cloudsim simulation tool and compared with existing multi-objective approaches. The results demonstrate that our approach reduces resources cost with respect to the user budgets.

Dynamic high bandwidth nodes for routing in MANETs

The main objective of the proposed work is to provide an optimal routing in wireless communication in order to improve the better achievable data rates. High bandwidth routing is the most desired advantage in networks with portable nodes. The main objective is to attain a high bandwidth route for increasing the delivery rate in mobile adhoc networks (MANETs). Dynamic high bandwidth (DHB) nodes are selected for consecutive data transmission in MANETs by evaluating their available virtual channel bandwidth using channel rate. The total efficiency of a node is measured through the packets currently received by a node; the corresponding delay and the bandwidth estimated from that received packet. Thereby the routes are computed by this dynamic estimation to improve routing capability in MANETS. Performance analysis of this proposed DHB-routing system is achieved by using the Network Simulator (NS-2) tool.

Channel Virtual Widening for Electric Information Acquisition System Based on LoRa and Edge Computing

Limited by the channel bandwidth of the terminal communication network in the power system electric information acquisition system, the energy user data at the end of the power system lack proper access mode. In this paper, based on the analysis and comparison of PLC technology, small wireless technology and GPRS technology, a new method of access communication based on LoRa technology and edge computing is proposed. The technology can take into account the advantages of low cost, strong coverage and anti-jamming, and can also improve the virtual bandwidth of the channel, and provide a solid foundation for high frequency data acquisition and mass delivery.

Verification of the Virtual Bandwidth SAR Scheme for Centimetric Resolution Subsurface Imaging From Space

This paper presents the first experimental demonstration of the virtual bandwidth synthetic aperture radar (VB-SAR) imaging scheme. VB-SAR is a newly developed subsurface imaging technique which, in stark contrast to traditional close proximity ground penetrating radar schemes, promises imaging from remote standoff platforms such as aircraft and satellites. It specifically exploits the differential interferometric SAR (DInSAR) phase history of a radar wave within a drying soil volume to generate high-resolution vertical maps of the scattering through the soil volume. For this study, a stack of C-band vertically polarized DInSAR images of a sandy soil containing a buried target was collected in the laboratory while the soil moisture was varied—first during controlled water addition, and then during subsequent drying. The wetting image set established the moisture-phase relationship for the soil, which was then applied to the drying DInSAR image set using the VB-SAR scheme. This allowed retrieval of high-resolution VB-SAR imagery with a vertical discrimination of 0.04 m from a stack of 1-m vertical resolution DInSAR images. This paper unequivocally shows that the basic principles of the VB-SAR technique are valid and opens the door to further investigation of this promising technique.

AN EXPERIMENT BASED EXAMINATION OF ENERGY OVERHEAD THROUGH VM MIGRATION

Abstract: The use of cloud computing has increased in recent days with tremendous benefits to users and also provoked to rise in total ownership cost due to swift increase in energy consumption of data centers. Out of various approaches, best of virtual machine placement policies can be exploited to reduce the energy consumption during migration in data centers. The virtual machine live migration during placement has enough potential to reduce energy consumption with certain level of utilization. One of the mechanisms to achieve energy efficiency is to manage the migration time parameter of live migration with appropriate network bandwidth in communication aware connected data centers. In spite of this, virtual machine size and network bandwidth have a great impact on energy consumption of sub systems during virtual machine live migration. To follow this study, in this paper, analysis has been made to see the impact of migration time on energy consumption of sub systems during guest virtual machine live migration. For experimentation, Kernel-based Virtual Machine (KVM) hypervisor and Virt Manager was used to perform live migration on Ubuntu 14.04 Linux machines in various conditions. Afterwards, the noted observations are validated with Pearson’s Correlation Coefficient statistical approach to study the strength of relationship of defined parameters.

V-BAG: A virtual bandwidth aggregation scheme for Internet of Things data

In order to meet the two crucial requirements of Internet of Things (support of a large number of Internet of Things devices and low power consumption), this article proposes a novel and efficient virtual bandwidth aggregation scheme for Internet of Things data. Since many Internet of Things applications require reliable Internet of Things data transmission, a Transmission Control Protocol is chosen as a transport protocol in this article. The proposed scheme consists of three salient functions: packet scheduler, estimator, and ACK buffer. The packet scheduler provides an efficient heterogeneous link selection using the proposed scheduling algorithm. The estimator provides an accurate delay and bandwidth estimation of heterogeneous wireless links using network layer information. Finally, the ACK buffer substantially boosts the performance of the scheduler and estimator with a simple ACK buffering scheme. Our extensive analysis using a numerical method and simulation corroborates the outstanding performance of the proposed scheme. Because of the salient functions of the proposed scheme, it can provide maximum capacity for future Internet of Things data transmission.

Virtual bandwidth SAR (VB-SAR) for centimetric-scale sub-surface imaging from space

Virtual bandwidth synthetic aperture radar (VB-SAR) is a radical new technique that promises, for the first time, sub-surface imaging at large stand-off distances applicable to airborne and spaceborne platforms. The scheme relies on understanding and exploiting the way a radar wave interacts with a soil volume. A wave passing through a soil to a buried object is delayed relative to the equivalent free-space path due to the higher relative permittivity of a soil, which is measured as a phase shift. This can equivalently be thought of as a shift in the real radar frequency to a virtual frequency. Temporal variations in soil moisture across a temporal stack of differential interferometric SAR (DInSAR) images can transport the real radar frequency at a pixel across a set of virtual frequencies to create a virtual bandwidth. Even small changes in moisture can produce large virtual bandwidths promising very high, centimetric-scale vertical resolutions: 1.6 cm at X-band and 8.6 cm at L-band for a 10% moisture change in a sandy soil. To produce a sub-surface depth profile at an image pixel, a Fourier transform is performed on the complex data stack collected across the DInSAR set. Retrieving the depth profile at each pixel across the 2D image provides a 3D map of the sub-surface backscattering through the scene. A description of the model is presented, and representative modelling results are presented to assess performance and application across different soil types, moisture regimes, and SAR platforms.

Analytical Analysis of In-Band Crosstalk, Out-of-Band Crosstalk and GVD-Based Power Penalties in DWDM and TDM/DWDM-PONS

In addition to the ever-increasing demand for broader bandwidth per user, which results from the continuous development of new bandwidth-hungry services and applications, the consequent upgrade from the currently deployed Time-Division Multiplexing Passive Optical Networks (TDM-PONs) to Next-Generation Optical Access Networks (NG-OANs) has become inevitable. Different architectures for creating a NG-OAN have been proposed in the literature. Among those architectures, the DWDM and TDM/DWDM-Based OANs are very promising candidates. They were mainly proposed to exploit the large wavelength counts available in the fibre (its virtual unlimited bandwidth) to achieve a significant increase in the system capacity. Moreover, they allow coexistence in an open access environment among different network operators. In this study, we first analyze the impact of in-band crosstalk, out-of-band crosstalk to evaluate the performance of the Arrayed Waveguide Grating (AWG). The reason to focus on the AWG is due to this optical device is used almost in all DWDM and TDM/WDM-PONs. We then turn our attention to analyze the impact of group velocity dispersion GVD to estimate the maximum allowable bit rate for optical transmission without the need for using a Dispersion Management Technique (DMT) and/or a Forward Error Correction Technique (FECT). The analysis was performed using Matlab software (The Math works, Inc., Natick, MA, USA) and confirms that the in-band crosstalk has a stronger effect than the out-of-band crosstalk because its noise floor is reached at a lower crosstalk noise and with fewer crosstalk components. The in-band crosstalk noise should be kept below -37 dB and -34 dB to maintain a power penalty of less than 1 dB if 15 and 7 in-band crosstalk components are considered, respectively. The out-of-band crosstalk noise should be kept below -20.3 dB and -17.18 dB to maintain a power penalty of less than 1 dB if 240 and 56 out-of-band crosstalk components are considered, respectively. It was observed that the GVD noise floor is reached at a shorter fiber length as the bit rate increases and it was confirmed that a significant improvement in which the GVD noise floor is reached at longer fiber can be achieved if an externally modulated, small spectral-width source is used when a bit rate of 622 Mbps, 1 Gps, or 2.5 Gbps is used. However, a dispersion management technique becomes necessary if the bit rate increases to 10 Gbps or more.

English

In this work a corporate network model consists of two separate buildings with four departments on different virtual local area network (VLAN) for the security purpose had been developed. The implementation was achieved using OPNET technology which really helped to reveal the traffic characteristics of network just like in a real life network. The central idea of this work is focused on the choice of likely bandwidth suitable for a corporate network design; this work categorically suggested that larger bandwidth is more preferable which is capable of handling large volume of traffic compare to the narrow bandwidth which usually suffers from delay and congestion that limits the number of the throughput at the destination. Key words: Virtual local area network (VLAN), bandwidth, IP address, Traffic and OPNET technology.

Distinction of Closely Spaced Targets using Pseudo Resolution Technique

The radar range resolution depends on signal bandwidth thereby detection of multiple closely spaced scattered points depends on bandwidth. To resolve this method of pseudo resolution is introduced which exploits the bandwidth allocation and increases the resolution of the overlapping scattered point (target/multipath). This resolution can be achieved by increasing the bandwidth of the received signal at receiver by stuffing zeros in between the samples received. This is why such bandwidth allocation is referred to as virtual bandwidth. The entire method is called Pseudo resolution. General Terms Multipath effects, Bandwidth exploration, Radar processing, target realization, intelligent transport system, collision avoidance and warning system.

A method for trust management in cloud computing: Data coloring by cloud watermarking

With the development of Internet technology and human computing, the computing environment has changed dramatically over the last three decades. Cloud computing emerges as a paradigm of Internet computing in which dynamical, scalable and often virtualized resources are provided as services. With virtualization technology, cloud computing offers diverse services (such as virtual computing, virtual storage, virtual bandwidth, etc.) for the public by means of multi-tenancy mode. Although users are enjoying the capabilities of super-computing and mass storage supplied by cloud computing, cloud security still remains as a hot spot problem, which is in essence the trust management between data owners and storage service providers. In this paper, we propose a data coloring method based on cloud watermarking to recognize and ensure mutual reputations. The experimental results show that the robustness of reverse cloud generator can guarantee users' embedded social reputation identifications. Hence, our work provides a reference solution to the critical problem of cloud security.

Game Based Virtual Bandwidth Allocation for Virtual Networks in Data Centers

In current data center, virtual machines may experience severely degraded performance due to the competing of network traffic on shared physical links. This situation is mainly caused by unreasonable and unfair allocation of the bandwidth resource. This paper presents a schema based on the idea of non-cooperative game theory in the field of microeconomics for dynamic bandwidth resource allocation between virtual networks. By modeling virtual networks as competing players and giving the pricing mechanism which decided by the physical substrate network and to guarantee efficiency, the schema can achieve optimal bandwidth allocation at the Nash equilibrium point of the game. We prove that the scheme admits a unique equilibrium point. Experimental results show that the bandwidth allocation between virtual networks is efficient and fair.

Virtualizing and Scheduling Optical Network Infrastructure for Emerging IT Services [Invited

Emerging IT service providers that aim at delivering supercomputing power available to the masses over the Internet rely on high-performance IT resources interconnected with ultra-high-performance optical networks. To adjust the provisioning of the resources to end-user demand variations, new infrastructure capabilities have to be supported. These capabilities have to take into account the business requirements of telecom networks. This paper proposes a service framework to offer Internet service providers dynamic access to extensible virtual private execution infrastructures, through on-demand and in-advance bandwidth and resource reservation services. This virtual infrastructure service concept is being studied in the CARRIOCAS project and implemented thanks to the scheduling, reconfiguration, and virtualization (SRV) component. This entity handles the service requests, aggregates them, and triggers the provisioning of different types of resources accordingly. We propose to adapt to envisioned heterogeneous needs by multiplexing rigid and flexible requests as well as coarse or fine demands. The goal is to optimize both resource provisioning and utility functions. Considering the options of advanced network bandwidth reservations and allocations, the optimization problem is formulated. The impacts of the malleability factor are studied by simulation to assess the gain.

Next-generation science information network for leading-edge applications

High-speed networks are definitely essential tools for leading-edge applications in many research areas, including nuclear fusion research. This paper describes a number of advanced features in the Japanese next-generation science information network, called SINET3, and gives researchers clues on the uses of advanced high-speed network for their applications. The network services have four categories, multiple layer transfer, enriched virtual private network, enhanced quality-of-service, and bandwidth on demand services, and comprise a versatile service platform. The paper also describes the network architecture and advanced networking capabilities that enable economical service accommodation and flexible network resource assignment as well as effective use of Japan's first 40-Gbps lines.