🏛️國立陽明交通大學機構典藏

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Weighted Routing in Hierarchical Multi-domain SDN Controllers
(2015)
Huang, Jian-Jhong
;
Chen, Ying-Yu
;
Chen, Chien
;
Chu, Yu Huang
;
資訊工程學系
In the common implementation of software defined networking where only one controller is used, tasks required by various applications may overwhelm the controller as the network grows, leading to degradation of the network performance. Some multi-controller architectures have been proposed to remedy such scalability issue. In this paper, we present our design and implementation of a routing application under a hierarchical multi-controller architecture. In this architecture, a network is partitioned into multiple domains, each of which is managed by a dedicated local controller, which is managed by a common global controller. The routing application is executed on the local and global controllers, jointly providing a routing service for each new flow. We provide effective mechanisms to reduce the link state that should be kept by the global controller. We propose a weight function on the links so that a weighted shortest path can be found that avoids the congested links on the network. Experiments results show that our routing application in the hierarchical multi-controller architecture has a great improvement over that of the single-controller architecture in terms various performance metrics.
A Low-Latency Multipath Routing Without Elephant Flow Detection for Data Centers
(2016)
Chakraborty, Suchandra
;
Chen, Chien
;
資訊工程學系
;
Department of Computer Science
Multipath routing in data center has been studied intensively in recent years in order to minimize the finish time of data transfer or the latency of message sending. Existing scheme of splitting traffic at the granularity of packets can cause reordered packets within a TCP flow. Another alternative scheme of splitting traffic at the granularity of a flow avoids packet reordering but may increase latency as it does not differentiate between elephant and mice flows. A newer efficient approach is to split elephants down into many mice flows, and distribute them uniformly at random over all paths. However, elephant detection is mandatory and the performance is largely depends on accuracy of the elephant detection. We propose, a simple yet effective multipath routing that leverage the same idea of splitting elephants down into many mice flows but without any farther requirement of elephant flow detection by using the hard time-out based flow removal feature of OpenFlow switches. Furthermore, we integrate a VLAN based routing scheme to addresses the challenges of cost-effective scalability. As per our simulation using mininet, we found a 44% reduction in overall flow completion time (FCT) compared to TinyFlow and 32% reduction in the consumption of flow table entry resources inside of aggregate switches in datacenter.
Scalable Topology-based Flow Entry Management in Data Center
(2016)
Hung, Chi-Hsiang
;
Huang, Chao-Wei
;
Wang, Li-Chun
;
Chen, Chien
;
資訊工程學系
Compared with current distributed networks, Software defined networking is an innovative technology to manage networks by a centralized controller with global visibility. OpenFlow is one kind of SDN protocols. It provides flow-level controllability of network traffic to simplify the management of the administrators of data center. Flow control rules used by OpenFlow in switch flow table are called flow entries. Modern commodity switches use TCAM to implement flow table because of its high matching speed. However, the general TCAM size of switch only accommodates up to thousands of flow entries due to its high cost-to-density ratio and high power consumption. It indicates that the maximal number of flow that can be controlled is restricted to the TCAM size of switch. That leads to several scalability issues, especially in a data center. In this paper, we propose a topology based flow entry management (TFEM) technique, which is a scalable and memory-efficient solution by exploiting the hierarchical topology characteristic to aggregate the uses of flow entries for most of the small flows in a data center. With the proposed downlink and uplink separated flow tables structure, our results show that TFEM can reduce the average number of flow entries by 50%similar to 78% for fat-tree topology against the traditional SDN without any switch hardware modification.
Enhancing Application Performance through OpenFlow Enabled Multi-homed Devices
(2014)
Tamba, Bully
;
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.

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🏛️國立陽明交通大學機構典藏

Search Results