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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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🏛️國立陽明交通大學機構典藏

Author: search.filters.author.Chen, ChienSubject: search.filters.subject.SDN

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Now showing 1 - 4 of 4
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    A Zero Flow Entry Expiration Timeout P4 Switch
    (2018-01-01)
    He, Cheng-Hung
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    Chang, Brian Y.
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    Chakraborty, Suchandra
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    Chen, Chien
    ;
    Wang, Li Chun
    Existing OpenFlow based flow expiry mechanisms rely on a fixed timeout after which the switch proactively removes the flow entries from its flow table. Assigning an appropriate value to this timeout presents a tradeoff between efficient flow table utilization and controller overhead.We propose a simple addition of a zero flow entry expiration timeout scheme to idle timeout mechanism on a P4 based switch that identifies the last packet of a TCP flow, and removes the corresponding flow entry from the flow table. It enables connections to be deleted from the flow table right after it finishes, instead of waiting to expire after it reaches the timeout threshold and causing unnecessary flow table occupation.
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    Network Aware VM Load Balancing in Cloud Data Centers Using SDN
    (2017-01-01)
    Tsygankov, Mykola
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    Chen, Chien
    ;
    資訊工程學系
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    電機工程學系
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    Department of Computer Science
    Despite being industry standard, load balancing via virtual machine (VM) migration methods in modern cloud data centers still exhibit two major performance issues: resulting system load balancing degree and total time till balanced state. Over the years research has been conducted to improve these metrics. Yet due to the fact that these issues influence each other, it has been a challenge to achieve substantial advancement in both metrics simultaneously. In this paper we study the problem of VM migration with load balancing and migration time constraints. We formulate this problem as a variation of multi-commodity minimum cost flow problem and show how both resulting degree of imbalance and a total migration time can be optimized together. We also propose a heuristic method based on Ant Colony Optimization family of algorithms. Through simulation results we show that our heuristic gives good performance results compared to optimal solutions to minimum cost flow problem. Furthermore, our method achieves on average twice faster migration time compared to existing methods, proposed in related works.
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    A Software Defined Network Architecture for GeoBroadcast in VANETs
    (2015)
    Liu, Yu-Chun
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    Chen, Chien
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    Chakraborty, Suchandra
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    資訊工程學系
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    資訊技術服務中心
    This paper proposes a Software Defined Network (SDN) architecture for GeoBroadcast in VANETs. We have implemented a component to automatically manage the geographical location of Road Side Units (RSUs), which are used as a basis for our GeoBroadcast routing. GeoBroadcast in a vehicular network supports periodic broadcast messages from a source vehicle to the destination vehicles that are located in a specific geographical region. In existing Intelligent Transport Systems (ITS), the GeoBroadcast mechanism can be implemented using traditional IP networking. Typically, every periodic warning messages received at nearest RSU from the source must be routed to the control center in ITS, where it is redirected to every other RSUs, that are located in the destination geographical region for broadcasting. As a result, huge overhead in the control center is produced and higher network bandwidth is consumed. However, in our SDN based GeoBroadcast mechanism, the first warning message received by the source RSU is sent to the SDN controller as a packet-in message. The SDN controller will decode the packet-in message and use topological and geographical information to set up the routing paths to the destination RSUs, by installing appropriate flow entries on the corresponding RSUs and intermediate switches, for the following periodic warning messages that are to be broadcasted. As per our simulation with OpenNet a significant reduction by 84% in controller overhead, 60% in network bandwidth consumption, and 81% in latency are achieved.
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    Enhancing Application Performance through OpenFlow Enabled Multi-homed Devices
    (2014)
    Tamba, Bully
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    Tseng, Kuo-Chun
    ;
    Chen, Chien
    ;
    Tseng, Chien-Chao
    ;
    資訊工程學系
    The increasing demand for mobile data usage is overwhelming our wireless network. However, most of these devices are equipped with multiple network interfaces (multi-homed) which when properly exploited have the potential to increase bandwidth capacity and ensure reliable connectivity. But some technical challenges are restricting our multimode devices to using one single interface at a time. In this paper, we advocate for the use of multiple interfaces simultaneously, which can achieve reliable network connectivity, allow applications to distribute their traffic over multiple interfaces, and aggregate the capacity of different paths. We proposed an OpenFlow-based Multiple WLAN Interface (OpenMWF) prototype, designed by embedding OpenFlow network resource controller and a data forwarding open virtual switch (OVS) in the network stack of the device operating system. A proof of concept implementation and evaluation was carried out using Web-based Real-Time Communication (WebRTC) interactive video conferencing and multi-source downloading utility (Aria2c) applications use cases. The result showed the approach yielded benefits for applications performance, over single interface usage.