| 1. |
- Fan, Xing, 1975-, et al.
(författare)
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Admission control for switched real-time Ethernet : scheduling analysis versus network calculus
- 2005
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Ingår i: Proc. of the Swedish National Computer Networking Workshop (SNCNW’05), Halmstad, Sweden, Nov. 23-24, 2005. ; , s. 4 s.-
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Konferensbidrag (refereegranskat)abstract
- Many approaches have been developed to give an estimation of the upper bound of the end-to-end delay or the response-time for real-time application, e.g., the Network Calculus (NC) model and the scheduling analysis. In this paper, we present an approach based on scheduling analysis to support guaranteed real-time services over standard switched Ethernet. Furthermore, we conduct a comparative study between these two admission control schemes, our novel algorithm and an NC-based algorithm. The simulation analysis shows that our feasibility analysis gives up to 50% higher utilization than the popular NC. Another advantage of our solution is that no additional hardware or software modification of the switch and the underlying standard. In our proposal, the traffic differentiation mechanism introduced by the IEEE 802.1D/Q standard and the standard hardware-implemented First Come First Served (FCFS) priority queuing are used in the switch and the source nodes. We have derived a feasibility analysis algorithm to ensure that the real-time requirements can be met. The algorithm also gives, as a sub-result, the needed buffer space in the end nodes and the switch. Moreover, our feasibility analysis supports variable-sized frames and switches with different bit-rates ports.
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| 2. |
- Fan, Xing, 1975-, et al.
(författare)
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Guaranteed real-time communication in packet-switched networks with FCFS queuing
- 2009
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Ingår i: Computer Networks. - Amsterdam : North Holland. - 1389-1286 .- 1872-7069. ; 53:3, s. 400-417
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a feasibility analysis of periodic hard real-time traffic in packet-switched networks using first come first served (FCFS) queuing but no traffic shapers. Our work constitutes a framework that can be adopted for real-time analysis of switched low-cost networks like Ethernet without modification of the standard network components. Our analysis is based on a flexible network and traffic model, e.g., variable-sized frames, arbitrary deadlines and multiple switches. The correctness of our real-time analysis and the tightness of it for network components in single-switch networks are given by theoretical proofs. The performance of the end-to-end real-time analysis is evaluated by simulations. Moreover, our conceptual and experimental comparison studies between our analysis and the commonly used Network Calculus (NC) shows that our analysis can achieve better performance than NC in many cases.
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| 3. |
- Fan, Xing, 1975-, et al.
(författare)
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Guaranteed Real-Time Communication in Packet-Switched Networks with FCFS queuing : Analysis and Simulations
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, we present a real-time analytical framework and the performance evaluation on our analysis. We propose a feasibility analysis of periodic hard real-time traffic in packet-switched networks using First Come First Served (FCFS) queuing but no traffic shapers. We choose switched Ethernet as an example to present the idea of our analysis and our experimental evaluations in this report.The remainder of the report is organized as follows. In Chapter 2, we define the network models, important concepts and terminology for real-time analysis. Chapter 3 presents our real-time analysis for isolated network elements. Chapter 4 gives end-to-end real-time analysis. Chapter 5 presents the performance evaluation of our results by simulation and comparison study and summarizes this report.
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| 4. |
- Fan, Xing, 1975-, et al.
(författare)
-
Guaranteed real-time services over standard switched Ethernet
- 2005
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Ingår i: The IEEE Conference on Local Computer Networks, 30th Anniversary. - New York, NY : IEEE Computer Society. - 0769524214 ; , s. 490-492
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Konferensbidrag (refereegranskat)abstract
- In this paper, we contribute with an approach to support guaranteed real-time services over standard switched Ethernet without additional hardware or software modification of the switch and the underlying standard. In our proposal, the traffic differentiation mechanism introduced by the IEEE 802.1D/Q standard and the standard hardware-implemented first come first served (FCFS) priority queuing are used in the switch and the source nodes. We have derived a feasibility analysis algorithm that can be used to ensure that the real-time requirements can be met. The algorithm also gives, as a sub-result, the needed buffer space in the end nodes and the switch. Moreover, our feasibility analysis supports variable-sized frames and switches with different bit-rates ports. The simulation analysis verifies our feasibility analysis.
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| 5. |
- Fan, Xing, 1975-, et al.
(författare)
-
Network component architectures from a real-time perspective
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, we survey different architectural features of network components for packet-switched networks. Especially, we have a real-time perspective in the study. We also discuss how different architectural features vary with different implementations of two standards, RapidIO and switched Ethernet.
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| 6. |
- Fan, Xing, 1975-
(författare)
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Real-Time Services in Packet-Switched Networks for Embedded Applications
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Embedded applications have become more and more complex, increasing the demands on the communication network. For reasons such as safety and usability, there are real-time constraints that must be met. Also, to offer high performance, network protocols should offer efficient user services aimed at specific types of communication.At the same time, it is desirable to design and implement embedded networks with reduced cost and development time, which means using available hardware for standard networks. To that end, there is a trend towards using switched Ethernet for embedded systems because of its hight bit rate and low cost. Unfortunately, since switched Ethernet is not specifically designed for embedded systems, it has several limitations such as poor support for QoS because of FCFS queuing policy and high protocol overhead.This thesis contributes towards fulfilling these requirements by developing (i) real-time analytical frameworks for providing QoS guarantees in packet-switched networks and (II) packet-merging techniques to reduce the protocol overhead.We have developed two real-time analytical frameworks for networks with FCFS queuing in the switches, one for FCFS queuing in the source nodes and one for EDF queuing in the source nodes. The correctness and tightness of the real-time analytical frameworks for different network components in a singel-switch neetwork are given by strict theoretical proofs, and the performance of our end-to-end analyses is evaluated by simulations. In conjunction with this, we have compared our results to Network Calculus (NC), a commonly used analytical scheme for FCFS queuing. Our comparison study shows that our anlysis is more accurate than NC for singel-switch networks.To reduce the protocol overhead, we have proposed two active switched Ethernet approaches, one for real-time many-to-many communication and the other for the real-time short message traffic that is often present in embedded applications. A significant improvement in performance achieved by using our proposed active networks is demonstrated.Although our approaches are exemplified using switched Ethernet, the general approaches are not limited to switched Ethernet networks but can easily be moified to other similar packet-switched networks.
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| 7. |
- Wang, Bin, et al.
(författare)
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Analysis of Efficient TDMA Schedules via the Fat-Tree Network with Real-Time Many-to-Many Communication
- 2006
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Ingår i: Proceedings of the IASTED International Conference on Parallel and Distributed Computing and Networks. - Anaheim, CA : ACTA Press. - 088986568X ; , s. 192-197
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Konferensbidrag (refereegranskat)abstract
- The Real-Time Many-to-Many (RTM2M) communication pattern is widely used in many parallel and distributed computing applications with time constraints such as radar signal processing. In this paper, we propose how to use TDMA (Time Division Multiple Access) to achieve efficient support for RTM2M over the fat-tree network built up on 4×2 switches (four children and two parents). Moreover, we have compared four different TDMA schedules in terms of the end-to-end delay and network utilization [1] and presented two of them in detail hereby. The general formulas of the end-to-end delay of two of the most interesting schedules are derived and simulations are represented to both verify the formulas and provide support for the conclusion from the viewpoint of the network utilization.
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