High Network Load Research Articles

Studying Semi-TCP and Its Application in Marine Internet

TCP protocol has good performance on the Internet, but its performance is significantly reduced when it is applied to Marine Internet (MI). How to improve the performance of TCP protocol in Marine Internet has become an important research topic. In this paper, an improved Semi-TCP is adopted for Marine Internet, and the implementation scheme of Semi-TCP congestion control is introduced. The exposed terminal problem and congestion control problem of high load networks are analyzed in detail. By using a timer, the congestion control algorithm is improved. Performance analysis and comparison of TCP-Lite, Semi-TCP-RTS, and improved Semi-TCP (Semi-TCP-RTS-V2) are carried out on Exata simulation platform, and the experimental results show that Semi-TCP-RTS-V2 has better transmission performance in ship ad hoc networks.

Performance maximization of network assisted mobile data offloading with opportunistic Device-to-Device communications

Mobile data traffic inside mobile operator’s infrastructure is increasing exponentially every year. This increasing demand forces mobile network operators (MNOs) to seek for alternative communication methods in order to relieve the traffic load in base stations, especially in highly populated and crowded environments. Network assisted data offload and Device-to-Device(D2D) communications are two prominent methods to help MNOs solve this problem. In this study, a data offload framework is developed that incorporates network assisted multiple attribute decision making (MADM) for best network selection and D2D communications for exploiting user proximity in crowded environments. The performance of the framework is evaluated with simulation results as well as analytic solutions and performance bounds. The simulation results indicate the superiority of incorporating network-based information besides user-based information in offloading decisions and demonstrates the significant benefits of D2D communications when the density of D2D users is properly adjusted. The simulation results depict that up to 168% and 200% increase in user satisfaction and throughput can be achieved under high network load scenarios at optimal D2D density.

Enhancing Cooperative Driving in IEEE 802.11 Vehicular Networks Through Full-Duplex Radios

On the path to zero fatalities on the roadways, all vehicles have to periodically broadcast cooperative awareness messages (CAMs) in a timely and reliable manner, even in areas of high traffic density. The carrier senses multiple access with collision avoidance (CSMA/CA) scheme of IEEE 802.11, the de-facto standard for vehicular communications, is known to offer no reliability to broadcast packets that cannot be acknowledged, and to poorly perform at high network load due to collisions and interference. In this paper, an enhanced CSMA/CA protocol is analyzed for vehicular networks, which improves the CAM timeliness and reliability by leveraging full-duplex (FD) transceivers on board. FD devices can listen to the channel while transmitting, thus making collision detection viable. A FD vehicle can detect a CAM collision while sending, promptly abort the packet and retransmit it later. Results achieved through an analytical model under mathematically tractable assumptions, and through extensive system-level simulations in a complex urban environment, show the effectiveness of the protocol to cope with direct collisions , especially in high traffic areas, paving the way towards the realization of cooperative automated driving.

Drop-Burst Length Evaluation of Urban VANETs

Networks performance is traditionally evaluated using packet delivery ratio (PDR) and latency (delay). We propose an addition mechanism the drop-burst length (DBL). Many traffic classes display varying application-level performance according to the pattern of drops, even if the PDR is similar. In this paper we study a number of VANET scenarios and evaluate them with these three metrics.Vehicular Ad-hoc Networks (VANETs) are an emerging class of Mobile Ad-hoc Network (MANETs) where nodes include both moving vehicles and fixed infrastructure. VANETs aim to make transportation systems more intelligent by sharing information to improve safety and comfort. Efficient and adaptive routing protocols are essential for achieving reliable and scalable network performance. However, routing in VANETs is challenging due to the frequent, high-speed movement of vehicles, which results in frequent network topology changes.Our simulations are carried out using NS2 (for network traffic) and SUMO (for vehicular movement) simulators, with scenarios configured to reflect real-world conditions. The results show that OLSR is able to achieve a best DBL performance and demonstrates higher PDR performance comparing to AODV and GPSR under low network load. However, with GPSR, the network shows more stable PDR under medium and high network load. In term of delay OLSR is outperformed by GPSR.

Improved protocols for spreading vehicle emergency messages in mobile ad hoc networks

This paper proposes relay node selection schemes for propagating vehicle emergency messages (EM) in vehicle mobile ad hoc networks (VMANETs). In the majority of VMANET applications, an EM is propagated in the form of broadcasting. But, typical broadcasting schemes cause some problems, such as high network load, delayed multi-hop propagation, and absence of a range control function, and so on. In this paper we present two competition based relay node selection schemes; one scheme is the Stem and Branch (S&B) protocol that makes use of the sender's location information, the other scheme is the least common neighbor (LCN) protocol that utilizes the neighbor lists. According to simulation results of highway traffic scenarios, the performance of proposed S&B and LCN protocols is better than that of the previous protocols in all areas and the number of forward messages is largely decreased in these proposed protocols.

A performance study for the multicast collision prevention mechanism for IEEE 802.11

In IEEE 802.11 networks a data packet is delivered simultaneously to multiple receivers through the multicast paradigm. The standard defines a simple mechanism that does not implement any error-recovery mechanism, thus, the reliability of the service provided to the multicast users is penalized. This issue is more important as the number of collisions increases due to a large number of active stations and/or a high load network. In this paper we carry out a detailed optimization study of the multicast collision prevention (MCP) mechanism, a highly-efficient multicast collision avoidance mechanism for IEEE 802.11 previously introduced by the authors. Besides a more in deep explanation of MCP, this study includes a comparative performance evaluation of the optimized MCP with the IEEE 802.11 standard. Results shown that, through this optimization, the number of collisions in MCP can be made negligible for any network load.

AN IMPROVED MAINTENANCE STRATEGY IN AD HOC ON-DEMAND ROUTING PROTOCOLS FOR MOBILE AD HOC NETWORKS

In high mobility and high traffic load network situations, the delay time is affected with high end-to-end delay in reactive routing protocols such as AODV. In this paper we proposed an enhanced receiver-based AODV (ERB-AODV) routing protocol by improving the maintenance phase in AODV. ERB-AODV protocol focuses on decreasing the end-to-end delay and the control overhead in high mobility and traffic load. The receiver node uses a controller agent to update the sender node of the current available path. The agent works depend on the history of receiving data packets. Using glomosim, the ERB-ADOV protocol outperforms the AODV protocol in high mobility and traffic load. Results show that, in high mobility, the delay is decreased by 81% and the control overhead is decreased by 77%. The delay is decreased by 91% in high traffic load, and decreases the control overhead by -77% compared with AODV protocol. These results show the improvement of network delay using the new maintenance strategy on on-demand routing protocols for MANETs.

Transport Mechanisms for Mobility Support in Optical Slot Switching-Based Next-Generation Mobile Backhaul Networks

In order to implement the next-generation (e.g., LTE-A) mobile backhaul networking segment, an optical slot switching solution called packet optical add/drop multiplexer (POADM) was previously proposed. Optical slot switching is at the same time a high capacity, energy-efficient, and low-latency optical transport network technology that relies on the direct transmission of data from base station to base station without resorting to time-consuming electronic processing and energy-hungry optoelectronic conversions. Low latency is an important requirement of mobile backhaul networks for real-time traffic such as Coordinated MultiPoint (CoMP) and POADM was shown to be compatible with the strict latency requirement of CoMP—1 ms end-to-end—even for very high network loads of 80% and above. However, user mobility was not taken into account. The traffic of users moving from one cell to another cell during handovers should also meet this strict requirement. In this paper, we propose and evaluate several transport mechanisms to support User Element mobility at the optical layer in a next-generation mobile backhaul network implemented using our previously proposed optical slot switching technology. We show with simulations that with smart introduction of additional electronic processing for handover traffic only (traffic of user elements that have moved from one cell to another), very strict latency constraints (sub-ms) can be met even for the time-sensitive mobile traffic.

In-channel misrouting suppression technique for deflection-routed networks on chip

Deflection routing, where port-contentions in routers are resolved by intentionally misrouting some of packets along unwanted directions instead of storing them, has been proposed as a promising approach for improving power and area efficiency of large-scale networks on chip (NoCs). However, at high network load, when packets are misrouted more frequently, the cost and energy benefits of this simple routing scheme are offset by the performance degradation. To address this problem, we propose a technique that uses small in-channel buffers to capture some of deflected packets before they take a misrouting hop. The captured packets are then looped-back to the routers where they suffered deflection and routed again. To improve the efficiency of this in-channel misrouting suppression scheme we also slightly modify the routing function of the deflection router by restricting the choice of productive directions for misrouted packets. Evaluations on synthetic traffic patterns show that the proposed misrouting suppression mechanism yields an improvement of 36.2% in network saturation throughput when implemented into the conventional deflection-routed network.

Cross-Layer Admission Control to Enhance the Support of Real-Time Applications in WSN

Real-time monitoring applications may be used in a wireless sensor network (WSN) and may generate packet flows with strict quality of service requirements in terms of delay, jitter, or packet loss. When strict delays are imposed from source to destination, the packets must be delivered at the destination within an end-to-end delay (EED) hard limit in order to be considered useful. Since the WSN nodes are scarce both in processing and energy resources, it is desirable that they only transport useful data, as this contributes to enhance the overall network performance and to improve energy efficiency. In this paper, we propose a novel cross-layer admission control (CLAC) mechanism to enhance the network performance and increase energy efficiency of a WSN, by avoiding the transmission of potentially useless packets. The CLAC mechanism uses an estimation technique to preview packets EED, and decides to forward a packet only if it is expected to meet the EED deadline defined by the application, dropping it otherwise. The results obtained show that CLAC enhances the network performance by increasing the useful packet delivery ratio in high network loads and improves the energy efficiency in every network load.

Propagation of Low Variability in Video Traffic

Currently popular HTTP-based video delivery services generate highly variable video traffic over small time scales. This paper confirms that with sufficient transmission bandwidth available to the video traffic, small time scale variations can be reduced to a level approaching the Poisson arrivals without experiencing degradation in the video quality. The primary result in this paper is that upon establishment of a low variability state, this state shows stable behavior. The state remains intact even under a high network load, a high packet loss rate, or a long propagation delay. Furthermore, the state traverses wired/wireless LANs and the Internet. This attractive feature can facilitate the development of more basic and efficient traffic control schemes. The feasibility of this approach to reducing video traffic variability is discussed from the viewpoint of the perceived video quality

Dual-mode inter-router communication channel for deflection-routed networks-on-chip

Deflection routing, characterized by routing simplicity and minimal in-router buffer resources, has recently emerged as a promising approach for improving power and area efficiency of on-chip networks. With this routing strategy, packet contentions in routers are resolved by intentionally misrouting some of packets along unwanted directions instead of storing them. However, at higher network loads, when the contentions are more frequent, packets take longer paths on average to their destinations, and thus increase the energy consumption, delay, and reduce the throughput in the network. To address this problem, we enhance the inter-router communication channels with a lightweight link-control mechanism that prevents unnecessary network hops by forcing deflected packets, when possible, to loop back to their current routers instead of being misrouted. The effect of the packet loop-backing is similar to that of storing deflected packet into a small central in-router buffer, but is accomplished with lower implementation cost (i.e. there is no need for additional buffer memory) and without any modification to the underlying router microarchitecture. Evaluations on synthetic traffic patterns show that the proposed misrouting suppression mechanism yields an improvement of 11.8---14.5 % in network saturation throughput when coupled with the conventional bufferless and buffered deflection-based routers.

Performance Analysis of the Transport Protocols Trickles and TCP under High-load Network Conditions

We study the performance of the Trickles protocol which is a transport-layer protocol for the TCP/IP architecture. We have implemented the original model of the Trickles protocol for the ns-2 simulator and defined performance metrics which were measured using ns-2 simulations.

An RSU-Coordinated Synchronous Multi-Channel MAC Scheme for Vehicular Ad Hoc Networks

This paper proposes a roadside unit (RSU)-coordinated synchronous multi-channel medium access control (MAC) scheme for vehicular ad hoc networks (VANETs). The proposed scheme allows the on board unit (OBU) to reserve service channels (SCHs) on the control channel (CCH) during almost the whole synchronous interval and supports simultaneous transmissions on different SCHs. It enhances the performance of VANETs and decreases the CCH congestion. Moreover, we use RSU to record the rendezvous information and broadcast it to the OBUs. This method avoids the multi-channel hidden terminal problem. An analytical model is developed to evaluate the aggregate throughput on SCHs. This model considers the following factors: non-safety message transmission probability in each synchronous interval, average size of the non-safety message, and the number of OBUs. Furthermore, the requirement of obtaining the maximum throughput is computed. Simulation results are provided to validate the analytical model and to demonstrate the improvement in throughput. The results indicate that the proposed scheme can provide higher aggregate throughput than that of the vehicular enhanced multi-channel MAC and IEEE 1609.4, and better performance in CCH congestion control especially under high network load conditions.

Design of Computer Application Building Automation Control System

The object of this research is building automation control system and to design the system by means of the computer application. First, I analyze the operating principle of the automatic monitored control system based on the computer technology, and I find that with the help of Ethernet switching engineering we can solve the problem about high network load and transmission delay of traditional building automation control system. At the same time, I design the overall structure of the automatic monitored control system. Then I learn the hardware control system and the implementation of the software, and the mainly representative object is the central air-conditioning control system. As the core component of the control system, PLC’s hardware and transducer are chosen. And I design the process of software control, data acquisition, communication device and other modules. Meanwhile, I finish the design of the procedure of PLC master control module and realize the software monitoring and control with the host computer software. Finally, I explore the remote monitoring software based on internet, and improve some problem like the spread of information during the monitoring in the past and develop the auxiliary function of short message reminder with the end of the integrated structure, idea and the structure based on the computer application and the design of the key part.

Notice of Violation of IEEE Publication Principles: Designing Energy Routing Protocol With Power Consumption Optimization in MANET

Notice of Violation of IEEE Publication Principles Designing Energy Routing Protocol with Power Consumption Optimization in by Shivashankar, H.N. Suresh, G. Varaprasad, and G. Jayanthi, in the IEEE Transactions on Emerging Topics in Computing, Vol.2, No.2, June 2014, pp.192-197 After careful and considered review, it has been determined that the above paper is in violation of IEEE's Publication Principles. One of the authors, Golla Varaprasad, falsified reviewer names and provided them as recommended reviewers for the manuscript. As technology rapidly increases, diverse sensing and mobility capabilities have become readily available to devices and, consequently, mobile ad hoc networks (MANETs) are being deployed to perform a number of important tasks. In MANET, power aware is important challenge issue to improve the communication energy efficiency at individual nodes. We propose efficient power aware routing (EPAR), a new power aware routing protocol that increases the network lifetime of MANET. In contrast to conventional power aware algorithms, EPAR identifies the capacity of a node not just by its residual battery power, but also by the expected energy spent in reliably forwarding data packets over a specific link. Using a mini-max formulation, EPAR selects the path that has the largest packet capacity at the smallest residual packet transmission capacity. This protocol must be able to handle high mobility of the nodes that often cause changes in the network topology. This paper evaluates three ad hoc network routing protocols (EPAR, MTPR, and DSR) in different network scales, taking into consideration the power consumption. Indeed, our proposed scheme reduces for more than 20% the total energy consumption and decreases the mean delay, especially for high load networks, while achieving a good packet delivery ratio.

Scalable Fast Scheduling for Optical Flow Switching Using Sampled Entropy and Mutual Information Broadcast

Optical flow switching is a promising architecture to service large transactions of end users with cost-effective and power-efficient direct access to all-optical networks. For dynamic sessions that are bursty, unscheduled, and only require short transmission times at the full rate of a single wavelength (approximately ones to tens of seconds), the network management and control effort can be substantial, even unimplementable if fast booking and initiation of flow service is needed. In this paper, we describe a fast scheduling algorithm that sets up end-to-end connections for users with urgent large transactions with a scheduling delay of slightly more than one round-trip time. This fast setup of connections is achieved by probing multiple lightpaths between the source and the destination. Probing multiple lightpaths is necessary for moderate to high network loads to achieve low blocking probability. However, the network burden of network-state updates and computational complexity of scheduling can be overwhelming and make the algorithm hard to scale to large networks. With the help of information about network regions periodically updated in the form of sampled entropy and mutual information of the network states, the required efforts can be substantially reduced. To minimize probing efforts and avoid unnecessarily tying up network resources, we use a modified Bellman — Ford Algorithm (Entropy — BF) to select the fewest lightpaths for probing that can satisfy a service-level-blocking probability agreement between the user and the network provider. By collapsing detailsof network states into scalar parameters for average entropy and mutual information, we can greatly reduce both the amount of network-state information collected and/or disseminated and the computation complexity of the lightpath selection process of the probing algorithm. The algorithm is also robust to variations of traffic statistics because it does not depend on detailed assumptions about the statistical model of the traffic, which is often unknown and highly variable in real networks. The throughput performance of this access protocol can be kept high while the network-state protocol burden and computation efforts are reduced by orders of magnitude.

Trigger-less readout architecture for the upgrade of the LHCb experiment at CERN

The LHCb experiment has proposed an upgrade of its detector in order to collect data at ten times its initial design luminosity. The current readout architecture will be upgraded by removing the existing first-level hardware trigger whose efficiency is limited for hadronic channels at high luminosity. The new readout system will record every LHC bunch crossing and send data to a trigger selection process performed entirely by software running in a computing farm. Therefore, the new readout system must cope with higher sub-detector occupancies, higher rate and higher network load. In this paper, we describe the architecture, functionalities and technological challenges of such an upgraded system.

Network Interactions and Performance of a Multifunction IEC 61850 Process Bus

New substation technology, such as nonconventional instrument transformers, and a need to reduce design and construction costs are driving the adoption of Ethernet-based digital process bus networks for high-voltage substations. Protection and control applications can share a process bus, making more efficient use of the network infrastructure. This paper classifies and defines performance requirements for the protocols used in a process bus on the basis of application. These include Generic Object Oriented Substation Event, Simple Network Management Protocol, and Sampled Values (SVs). A method, based on the Multiple Spanning Tree Protocol (MSTP) and virtual local area networks, is presented that separates management and monitoring traffic from the rest of the process bus. A quantitative investigation of the interaction between various protocols used in a process bus is described. These tests also validate the effectiveness of the MSTP-based traffic segregation method. While this paper focuses on a substation automation network, the results are applicable to other real-time industrial networks that implement multiple protocols. High-volume SV data and time-critical circuit breaker tripping commands do not interact on a full-duplex switched Ethernet network, even under very high network load conditions. This enables an efficient digital network to replace a large number of conventional analog connections between control rooms and high-voltage switchyards.

Performance analysis of trickles and TCP transport protocols under high-load network conditions

We present our results on performance analysis of the Trickles protocol which is a transport-layer protocol of TCP/IP architecture. Our approach relies on the original model of the protocol which have been made for ns-2 simulator. We create a model of the network and measure performance metrics for the Trickles protocol and standard variants of the TCP protocol.