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Design and Implementation of TCP-Friendly Meters in P4 Switches
(2020-08-01)
Wang, Shie-Yuan
;
Hu, Hsien-Wen
;
Lin, Yi-Bing
;
資訊工程學系
;
Department of Computer Science
Metering the traffic of a flow and dropping the portion of traffic that exceeds the target rate set by the meter is very important to provide quality of service (QoS) in a network. Most existing switches on the market provide the meter function. Although these meters regulate the traffic of a UDP flow very well, according to our tests, they are not TCP-friendly. For example, we found that a TCP flow passing the meter of a commercial switch can only achieve about 10% of the target rate. Based on our studies, we found that this poor performance is due to the bad interactions between the TCP congestion control and the meter function. In this paper, we design and implement a TCP-friendly meter in the packet processing pipelines of a P4 switch. Experimental results show that our meter regulates a TCP flow very well and can maintain its achieved rate within 5% of the target rate. Compared with the meters in several hardware switches, our meter improves the achieved rate of a TCP flow by almost 85% of the target rate.
GGRA: A Feasible Resource Allocation Scheme by Optimization Technique for IEEE 802.16 Uplink Systems
(2010-01-01)
Chang, Chung-Ju
;
Chiu, Yin
;
Feng, Kai-Ten
;
Ren, Fang-Ching
;
電信工程研究所
Generally, optimization techniques for resource allocation of OFDMA systems are infeasible for real-time applications. In this paper, we propose a genetic algorithm with subscriber station (SS) grouping resource allocation (GGRA) scheme for IEEE 802.16 uplink systems. The GGRA scheme firstly designs a rate assignment strategy, applied with a predefined residual lifetime, to allocate resource to each service dynamically. It then aggregates high correlation SSs into the same group, where the SSs will be allocated to different slots so as to avoid mutual user interference. Finally, the GGRA scheme finds an optimal assignment matrix for the system by the genetic algorithm, based on the SS groups to greatly lessen the computation complexity. The GGRA scheme can also maximize system throughput and fulfill QoS requirements. Simulation results show that the proposed GGRA scheme performs better than the EFS algorithm [6] and the MLWDF algorithm [7] in system throughput, voice/video packet drop rate, unsatisfied ratio of HTTP users/packets, and FTP throughput. The computation complexity of the GGRA scheme is also tractable and thus feasible for real-time applications.
A green radio resource allocation scheme for LTE-A downlink systems with CoMP transmission
(2014-08-01)
Chung, Wen-Ching
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Chang, Chung-Ju
;
Teng, Hsin-Ying
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, we propose a green radio resource allocation (GRRA) scheme for LTE-advanced downlink systems with coordinated multi-point (CoMP) transmission to support multimedia traffic. The GRRA scheme defines a green radio utility function, which is composed of the required transmission power, assigned modulation order, and the number of coordinated transmission nodes. By maximizing this utility function, the GRRA scheme can effectively save transmission power, enhance spectrum efficiency, and guarantee quality-of-service requirements. The simulation results show that when the traffic load intensity is greater than 0.7, the GRRA scheme can save transmission power by more than 33.9 and 40.1 %, as compared with the conventional adaptive radio resource allocation (ARRA) scheme (Tsai et al. in IEEE Trans Wireless Commun 7(5):1734-1743, 2008) with CoMP and the utility-based radio resource allocation (URRA) scheme (Katoozian et al. in IEEE Trans Wireless Commun 8(1):66-71, 2009) with CoMP, respectively. Besides, it enhances the system throughput by approximately 5.5 % and improves Jain's fairness index for best effort users by more than 155 % over these two ARRA and URRA schemes.
Benchmarking handheld graphical user interface: Smoothness quality of experience
(2018-05-01)
Lin, Ying-Dar
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Chu, Edward T. -H.
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Wen, Chien-Ling
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Lai, Yuan-Cheng
;
Chen, I-Ching
With the rapid growth of smartphones in the market, the smoothness of smartphones, how quickly and well smartphones react to a user's input, becomes a crucial factor consumers consider when making buying decisions. However, there is no benchmark for comparing the smoothness of one phone against another. In this paper, a handheld smoothness evaluation over regression (HSER) model was developed to make a fair evaluation. A video was first made and the several key indexes were extracted to represent behavior-based smoothness quality of services (BQoS). We built up a relationship between BQoS and behavior-based smoothness quality of experience (BQoE), and converted BQoE to handheld smoothness quality of experience. Our experiment results show that maximal frame interval and number of frame intervals are the two most critical indexes that indicate smoothness. The proposed HSER model is able to fairly evaluate the smoothness of smartphones because the error rate of the HSER model is less than 9% for a single behavior.
Role-based Campus Network Slicing
(2016-01-01)
Chen, Chien-Hsin
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Chen, Chien
;
Lu, Ssu-Hsuan
;
Tseng, Chien-Chao
;
資訊工程學系
The Internet has evolved greatly in this decade. For economic benefits, the management of Internet networks needs to adapt to mass changes without huge modifications in hardware and software. Especially in campus networks, there are a variety of users and devices with different Quality of Service (QoS) requirements and management policies. Software-defined networking (SDN) decouples the data and control planes. The separated control plan resides on a centralized controller to make networks easier to manage. In this paper, a role-based SDN campus network slicing is proposed by utilizing an authentication controller and the virtualization technology of FlowVisor to divide the campus network into several virtual networks according to the types of users. However, the mapping between the devices' MAC addresses and the users' roles results in a heavy loading problem on FlowVisor. Therefore, a VLAN-based slicing is introduced in this framework to offload the workload of FlowVisor for classifying packets into corresponding slices. Packets are appended with VLAN tags for recognizing types of users to lower the overhead of FlowVisor. Analyses of experimental results show that compared with MAC-based slicing, VLAN-based slicing can reduce the flow setup latency by 14% to 60% depending on the number of devices.
On Different-Dimensional Deployment Problems of Hybrid VANET-Sensor Networks with QoS Considerations
(2017-02-01)
Lin, Chun-Cheng
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Chen, Peng-Chung
;
Chang, Li-Wei
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
To enhance vehicular ad hoc networks (VANETs) with the ability to detect road conditions, hybrid VANET-sensor networks (HVSNs) additionally deploy a large number of wireless sensors on road sides, so as to provide a safer driving environment. Most of the previous works on network deployment problems considered too simplified problem settings, and few of them focused on deploying HVSNs. To meet more practical requirements, this paper investigates the problem of deploying roadside units (RSUs) to serve sensors on three different-dimensional road settings (i.e., a one-dimensional road, a road represented as grid points, and a dense network environment) in HVSNs with two objectives (i.e., to minimize the total distance and the total number of hops from sensors to their respective closest RSUs) and two QoS constraints (i.e., for maximal number of hops and capacity). Achieving the two objectives can effectively decrease the probability of transmission interference and lead to shorter transmission time to inform drivers of unexpected events. Since the optimal deployment problems for a grid road and a dense HVSN cannot be solved analytically, this paper creates mathematical programming models for the problems, and further proposes an improved harmony search algorithm. By simulation in different-size instances and statistical analysis, the proposed approaches show promising performance in solving the problems.
Adaptive router node placement with gateway positions and QoS constraints in dynamic wireless mesh networks
(2016-10)
Lin, Chun-Cheng
;
Chen, Teng-Huei
;
Chin, Hui-Hsin
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Conventionally, router node placement is concerned with placing only routers to serve clients; and gateway placement is concerned with placing only gateways to achieve some requirements for routers. More generally, this work considers the placement with routers and gateways simultaneously, while clients can move based on their own willingness. That is, this work investigates the adaptive placement problem of a dynamic wireless mesh network (dynWMN) consisting of mesh clients, mesh routers, and Internet gateways. Given fixed positions of Internet gateways, this problem is to adjust positions of mesh routers dynamically to make each mesh client connected with some gateway via multi-hop communication at different times, when each mesh client may switch on or off network access, so that both network connectivity and client coverage are maximized, subject to the Quality of Service (QoS) constraints of delay hops, relay load, and gateway capacity. To avoid almost-overlapping routers and few clients-covered routers in router node placement, this work further proposes a novel particle swarm optimization approach with three local search operators. In simulation of dynWMNs, dynamics of mesh clients can be characterized by a Markov chain, and hence, their stable states can be derived theoretically and are used as criteria of evaluating performance, by which the proposed approach shows promising performance and adaptability to topology changes at different times. (C) 2016 Elsevier Ltd. All rights reserved.
An Intelligent Priority Resource Allocation Scheme for LTE-A Downlink Systems
(2012-06)
Chung, Wen-Ching
;
Chang, Chung-Ju
;
Wang, Li-Chun
;
電機學院
;
College of Electrical and Computer Engineering
In this paper, we propose an intelligent priority resource allocation (iPRA) scheme for long term evolution-advanced (LTE-A) downlink systems with multimedia traffic. The iPRA scheme intelligently computes priorities for users by using fuzzy inference system so as to enhance system throughput and attain high Jain fairness index while guarantee QoS requirements. Simulation results show that the iPRA scheme can achieve higher system throughput and better QoS requirement guarantee than conventional radio resource allocation schemes in high traffic load, while attains a rather large Jain fairness index.
Design and Evaluation of a High Throughput MAC with QoS Guarantee for Wireless LANs
(2009)
Kuo, Yaw-Wen
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Lee, Tsern-Huei
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Huang, Yu-Wen
;
Hsieh, Jing-Rong
;
電信工程研究所
The IEEE 802.11e and the IEEE 802.11n focus on quality of service (QoS) and enhancements for high throughput respectively. Modern wireless LAN (WLAN) products should integrate both features. This paper presents a design of a high throughput MAC with QoS guarantee which combines the Hybrid Coordination Function (HCF) of the 802.11e with the frame aggregation technique in the 802.11n. The basic idea of the design is to improve the throughput of best-effort traffic under the constraint that QoS is just met for real-time traffic. Simulation results show that the proposed MAC has high channel utilization and the delay of best-effort traffic is also reduced.
Wireless Mesh Router Placement with Constraints of Gateway Positions and QoS
(2015)
Lin, Chun-Cheng
;
Chen, Tung-Huei
;
Jhong, Shun-Yu
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The past studies on router node placement for wireless mesh networks (WMNs) did not consider placement of Internet gateways. Therefore, mesh routers and mesh clients can only communicate locally. The problem in this paper is to maximize both network connectivity and client coverage for the router node placement in WMNs consisting of mesh routers, mesh clients, and Internet gateways, subject to three QoS constraints: delay, relay load, and Internet gateway capacity. By visualizing the placements in previous works, we discover two main drawbacks: overlapping and coverless. To solve them, this paper presents a novel particle swarm optimization approach. Performance of the proposed approach is verified by simulation.

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