| 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. |
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| 3. |
- Fan, Xing, 1975-, et al.
(författare)
-
Efficient Many-to-Many Real-Time Communication Using an Intelligent Ethernet Switch
- 2004
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Ingår i: Proceedings of the 7<sup>th</sup> International Symposium on Parallel Architectures, Algorithms and Networks, 2004. - Piscataway, N.J. : IEEE. - 0769521355 ; , s. 280-287
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Konferensbidrag (refereegranskat)abstract
- This paper presents a solution for efficient many-to-many communication over switched Ethernet. The performance of using an ordinary switch and an intelligent switch is compared, and the results of the analysis based on 100 Mbit/s fast Ethernet show that an intelligent switch used to handle many-to-many communication can give better performance (shorter latency and higher utilization) than an ordinary switch. We also extend the network to serve many-to-many traffic with real-time demands by adding a thin software layer to the intelligent Ethernet switch and the end-nodes. Earliest deadline first (EDF) scheduling is used.
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| 4. |
- Fan, Xing, 1975-, et al.
(författare)
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Efficient Support for High Traffic-Volumes of Short-Message Real-Time Communication Using an Active Ethernet Switch
- 2004
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Ingår i: Proceedings of the 10th International Conference on Real-time and Embedded Computing Systems and Applications (RTCSA’04). ; , s. 517-533
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Konferensbidrag (refereegranskat)abstract
- There are several different types of communication traffic with real- time demands apparent in distributed industrial and embedded systems, for example, group communication and process synchronization. The length of these messages is often very short but the traffic volume might be really high. Standard network protocols do not normally reach very high utilization for such small messages. This paper presents a solution to efficiently support real-time short message communication over switched Ethernet. In our proposal, the Ethernet switch and the end-nodes are enhanced to combine several short messages into an Ethernet frame to improve the performance, and to give the short-message traffic real-time support on two levels, short-frame level and Ethernet frame level. Earliest Deadline First (EDF) scheduling is used in the switch and in the source nodes on both these two levels. We have characterized the performance of the network in terms of channel utilization and the number of accepted real-time channels, by simulations of the network assuming Fast Ethernet. We also show, by example, that we can reach an improvement of the possible short-message rate of 66%.
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| 5. |
- 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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| 6. |
- 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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| 7. |
- Fan, Xing, 1975-, et al.
(författare)
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Guaranteed Real-Time Services in Switched Ethernet Networks with Deadline Scheduling in the End Nodes
- 2004
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a switched Ethernet network that supports real-time communication with guaranteed bit rate and end-to-end delay bound. In our proposal, the source nodes use Earliest Deadline First (EDF) scheduling, while the switch uses First Come First Served (FCFS) to control periodic real-time traffic belonging to logical realtime connections. The schedulability condition is drawn and the end-to-end worst-case delay bound is derived for guaranteed real-time traffic, which also gives, as a sub-result, the needed buffer space in the switch. Moreover, different traffic classes are prioritized and put into different output queues in the end nodes and the switch, which minimizes the interference with other traffic when transmitting periodic time-critical messages. The solution requires no additional hardware or software modifications of the switch and the underlying standard. It is based purely on software implementation in the end nodes. Furthermore, the EDF scheduling strategy used in the source nodes allows good resource utilization, while the FCFS scheduling used in the switch limits the switch processing overhead. The paper presents simulation analysis for Fast Ethernet, which verifies our approach of guaranteeing real-time transmission at the same time as achieving high utilization.
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| 8. |
- Fan, Xing, 1975-, et al.
(författare)
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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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| 9. |
- Fan, Xing, 1975-, et al.
(författare)
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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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| 10. |
- Fan, Xing, 1975-
(författare)
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Real-Time Communication Services for Distributed Computing over Switched Ethernet
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In modern and future parallel and distributed processing, a large part of computation overhead comes from communication. This can be minimized if the network protocol offers the user services that are aimed at specific types of communication used in these applications. Other important properties of distributed processing applications are time-deterministic latency and guarantees to meet deadlines. Moreover, an important trend is to implement distributed real-time applications on top of standard Ethernet based networks. Therefore, in this thesis, we focus on developing and analyzing how to efficiently support real-time communication services for distributed computing applications over switched Ethernet. The network architecture currently assumed is a switched Ethernet network with only one switch.The work has resulted in proposed Switched Ethernet networks that offer additional features for parallel and distributed real-time processing. An active Ethernet switch concept is proposed to provide efficient support for different user services, including many-to-many communication and other group communication services with high traffic volumes of short messages. Meanwhile, the real-time support for these special communication patterns is addressed by incorporating deadline-based scheduling in the switch and the end nodes.Moreover, this thesis addresses real-time services by proposing an alternative solution. In this proposal, the Earliest Deadline First (EDF) algorithm is only used in the source nodes to support real-time traffic with a guaranteed bit rate and end-to-end worst-case delay bound. The thesis also reports a feasibility analysis for hard real-time traffic, which also produces figures on the minimum buffer sizes in the switch to be able to guarantee real-time demands. Meanwhile, differentiation of heterogeneous traffic is considered in the proposed system by placing traffic into several priority classes with distinctly different QoS levels.The performance of the proposed methods is evaluated in simulations and calculations. It is shown that the different Ethernet extensions, in many cases, are efficient choices for distributed computing systems.
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