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In this paper, we implemented OpenFlow scheduled bundle in the Open vSwitch software switch and evaluated its performance in SDN testbed networks under different scenarios. The scheduled bundle is a very new mechanism proposed in the OpenFlow protocol for achieving consistent updates among multiple SDN switches. However, this feature has not been supported in any hardware SDN switches or any software...
Traceroute is a very useful troubleshooting tool. It reveals the routing path taken by a packet destined to a remote host. Traceroute is originally designed for the legacy IP network. However, the mechanism used by it does not work in an SDN network. In an SDN network, there has been a similar tool called SDN traceroute that provides similar functions as traceroute. However, SDN traceroute does not...
In this paper, we designed, implemented, and evaluated the performance of software OpenFlow flow counters in a bare metal commodity switch. Normally, flow counters are implemented in hardware for line-rate operations and their number needs to be very large to support a large flow-based SDN network. Although these hardware counters operate very fast, they greatly increase the cost of an OpenFlow switch...
Openvswitch is the most popular software implementation of an OpenFlow switch on the Linux system. Its current implementation includes a kernel module and a user space daemon. To connect with an OpenFlow controller and handle all the command message traffic, Openvswitch needs to transfer control messages between the user space and the kernel space of the Linux system frequently. When the amount of...
In this paper, we design and implement a scheme to build an optimal spanning tree over a hybrid network composed of SDN and legacy switches. SDN is an emerging network technology and gradually gaining adoption worldwide. However, during the technology transition period, which may last several years from now on, inevitably SDN switches and legacy switches will need to coexist in a network. In a legacy...
Advanced Persistent Threat (APT) poses a serious threat to cyber security, and its unique high unpredictability, deep concealment and grave harmfulness make the traditional network monitoring technology facing unprecedented challenges in the background of massive and complicated network traffic. This paper aimed for the urgent demand of APT network monitoring. Relying on the rapid development of big...
A Key Establishment Protocol for Anonymous Wireless Roaming (KEP-AWR) allows a wireless user such as a Wi-Fi/WiMAX enabled laptop or smartphone to establish a session key with a foreign server and also roam from one foreign network to another in an anonymous way such that besides the involving foreign server and the user's home server, no one can find out who the user is. Most existing KEP-AWR protocols...
Radio Frequency Identification (RFID) has recently played an important role in wireless sensing network. However, if multiple passive tags are simultaneously transmitted to the reader, the reader is unable to identify the tags. This will reduce the efficiency of a RFID system. To solve this problem, we propose a modified anti-collision algorithm based on ALOHA protocol to improve the performance in...
In this decade, peer-to-peer (P2P) applications have emerged as popular tools for sharing data and they have gained much attention. Such P2P applications build overlay networks on top of existing infrastructure networks and disseminate data in a peer-to-peer manner. How well the P2P overlay network maps onto the underlying physical network topology can significantly impact P2P application performances...
RapidIO is an open standard that provides high-performance interconnect for chip-to-chip, board-to-board, and chassis-to-chassis communications. In this paper, we present an executable RapidIO interconnect in which an improved Buffer structure based on flow control is put forward. It helps to provide a smooth data flow, strong built-in error detection and error recovery mechanisms. It is tested to...
NCTUns is a novel network simulator/emulator that has many unique features over traditional network simulators/emulators. It runs on Linux and many papers/projects have used it for wireless vehicular network research. According to the NCTUns website (http://NSL.csie.nctu.edu.tw/nctuns.html), as of December 24, 2009, more than 16,164 people from 137 countries in the world have registered and downloaded...
The IEEE 802.11(p)/1609 network is a promising candidate for future vehicular communication networks. Due to the deployment cost consideration, roadside units (RSUs) in such networks are usually installed only at hot spots and intersections, causing the service coverage of RSUs to be discontinuous. To overcome this problem, multihop data forwarding among vehicles can be used to extend the service...
Node identification is one of the most important issues to wireless sensor network security. Current approaches use cryptographic authentication and certification tools to ensure the node identification, while this paper introduces an intuitive method to identify a node by measuring its clock skew. This method is based on our observation that every sensor node has a unique clock skew value that is...
NCTUns is a novel network simulator and emulator that has many unique features over traditional network simulators and emulators. It is an open-source software running on Linux and is being used by many researchers in the world. According to the NCTUns official Web site (http://NSL.csie.nctu.edu.tw/nctuns.html), as of June 1, 2008, more than 11,546 people from 124 countries have registered and downloaded...
The paper proposes a fragment and rate matching (FaRM) MAC protocol for wireless local area networks (LANs) to resist the frequent changing of channel quality and increase the network throughput. In wireless environments, channel quality varies with time. FaRM dynamically detects the current SNR to estimate the channel quality through the control frame exchanges. A Finite State Markov Chain (FSMC)...
The IEEE 802.11(p)/1609 standard is an emerging technology for vehicular communication networks. It amends the IEEE 802.11-2007 standard and defines a new WAVE operational mode for vehicular environments. The WAVE mode utilizes a combined FDMA/TDMA scheme to manage network bandwidth. In this mode, a node must periodically switch its frequency channel between two different channels over time. Such...
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