scholarly journals Worst case performance bounds for multimedia flows in QoS-enhanced TNPOSS network

2011 ◽  
Vol 8 (3) ◽  
pp. 890-908
Author(s):  
Ke Xiong ◽  
Yu Zhang ◽  
Shenghui Wang ◽  
Zhifei Zhang ◽  
Zhengding Qiu
Keyword(s):  
Network Optimization ◽  
Network Performance ◽  
Buffer Management ◽  
Buffer Size ◽  
Network Calculus ◽  
Performance Bounds ◽  
Transmission Scheme ◽  
Worst Case ◽  
Delay Bound ◽  
Packet Length

Network performance bounds, including the maximal end-toend (E2E) delay, the maximal jitter and the maximal buffer backlog amount, are very important for network QoS control, buffer management and network optimization. QoS-enhanced To Next-hop Port Sequence Switch (QTNPOSS) is a recently proposed transmission scheme to achieve scalable fast forwarding for multimedia applications. However, the existing E2E delay bound of QTNPOSS network is not tight. To this end, this paper presents a lower E2E delay bound for QTNPOSS networks by using the network calculus theory, where the inherent properties (e.g. packet length and peak rate) of the flow are taken into account. Besides, the buffer size bound and the jitter bound of QTNPOSS network are also presented. Moreover, by extensive numerical experiments, we discuss the influences of the Long Range Dependence (LDR) traffic property and the Weighted Fair Queuing (WFQ) weight on the proposed network performance bounds. The results show that the WFQ weight influences the bounds more greatly than the LRD property.

scholarly journals Network Calculus-Based Latency for Time-Triggered Traffic under Flexible Window-Overlapping Scheduling (FWOS) in a Time-Sensitive Network (TSN)

2021 ◽  
Vol 11 (9) ◽  
pp. 3896
Author(s):  
Khaled M. Shalghum ◽  
Nor Kamariah Noordin ◽  
Aduwati Sali ◽  
Fazirulhisyam Hashim
Keyword(s):  
Real Time ◽  
Connected Vehicles ◽  
Network Calculus ◽  
Timing Constraints ◽  
Traffic Scheduling ◽  
Worst Case ◽  
Continuous Increase ◽  
Scheduled Traffic ◽  
Support Time ◽  
New Framework

Deterministic latency is an urgent demand to pursue the continuous increase in intelligence in several real-time applications, such as connected vehicles and automation industries. A time-sensitive network (TSN) is a new framework introduced to serve these applications. Several functions are defined in the TSN standard to support time-triggered (TT) requirements, such as IEEE 802.1Qbv and IEEE 802.1Qbu for traffic scheduling and preemption mechanisms, respectively. However, implementing strict timing constraints to support scheduled traffic can miss the needs of unscheduled real-time flows. Accordingly, more relaxed scheduling algorithms are required. In this paper, we introduce the flexible window-overlapping scheduling (FWOS) algorithm that optimizes the overlapping among TT windows by three different metrics: the priority of overlapping, the position of overlapping, and the overlapping ratio (OR). An analytical model for the worst-case end-to-end delay (WCD) is derived using the network calculus (NC) approach considering the relative relationships between window offsets for consecutive nodes and evaluated under a realistic vehicle use case. While guaranteeing latency deadline for TT traffic, the FWOS algorithm defines the maximum allowable OR that maximizes the bandwidth available for unscheduled transmission. Even under a non-overlapping scenario, less pessimistic latency bounds have been obtained using FWOS than the latest related works.

scholarly journals Cross Layer Optimization and Simulation of Smart Grid Home Area Network

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Lipi K. Chhaya ◽  
Paawan Sharma ◽  
Adesh Kumar ◽  
Govind Bhagwatikar
Keyword(s):  
Smart Grid ◽  
Network Performance ◽  
Performance Enhancement ◽  
Hierarchical Architecture ◽  
Buffer Size ◽  
Cross Layer ◽  
Area Network ◽  
Frame Aggregation ◽  
Cross Layer Optimization ◽  
Layered Approach

An electrical “Grid” is a network that carries electricity from power plants to customer premises. Smart Grid is an assimilation of electrical and communication infrastructure. Smart Grid is characterized by bidirectional flow of electricity and information. Smart Grid is a complex network with hierarchical architecture. Realization of complete Smart Grid architecture necessitates diverse set of communication standards and protocols. Communication network protocols are engineered and established on the basis of layered approach. Each layer is designed to produce an explicit functionality in association with other layers. Layered approach can be modified with cross layer approach for performance enhancement. Complex and heterogeneous architecture of Smart Grid demands a deviation from primitive approach and reworking of an innovative approach. This paper describes a joint or cross layer optimization of Smart Grid home/building area network based on IEEE 802.11 standard using RIVERBED OPNET network design and simulation tool. The network performance can be improved by selecting various parameters pertaining to different layers. Simulation results are obtained for various parameters such as WLAN throughput, delay, media access delay, and retransmission attempts. The graphical results show that various parameters have divergent effects on network performance. For example, frame aggregation decreases overall delay but the network throughput is also reduced. To prevail over this effect, frame aggregation is used in combination with RTS and fragmentation mechanisms. The results show that this combination notably improves network performance. Higher value of buffer size considerably increases throughput but the delay is also greater and thus the choice of optimum value of buffer size is inevitable for network performance optimization. Parameter optimization significantly enhances the performance of a designed network. This paper is expected to serve as a comprehensive analysis and performance enhancement of communication standard suitable for Smart Grid HAN applications.

Benchmarks Comparing for IEEE 802.15.4 with Hidden Terminals

2011 ◽  
Vol 403-408 ◽  
pp. 1950-1955
Author(s):  
Zhen Hua Wu ◽  
Xiao Chuan Huang ◽  
Jian Shu
Keyword(s):  
Wireless Network ◽  
Network Performance ◽  
Ieee 802.15.4 ◽  
Performance Degradation ◽  
Data Generation ◽  
Main Research ◽  
Network Load ◽  
Hidden Terminals ◽  
Hidden Terminal ◽  
Packet Length

Hidden terminal problem (HTP) has been a main research aspect in the field of wireless network performance analyzing and testing since it was formulated in 1970s. This article conducts a relatively comprehensive testing on the performance degradation of IEEE 802.15.4 network, which is beacon enabled, star architecture and using slotted CSMA/CA algorithm, due to HTP. All simulate experiments are conducted in NS-2. The experiment results show that: data generation form has little impact on HTP; packet length has more effect on HTP than the number of packets; HTP is trivial when network load is lower than 10%; acknowledge mechanism enlarges extremely HTP; increasing the value of beacon order (BO) is help for alleviating HTP when BO value is small than 6. These conclusions are useful for understanding the features of HTP in IEEE 802.15.4 networks.

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