共查询到20条相似文献，搜索用时 15 毫秒
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With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologies for the network control and management.These two technologies could be combined together to construct a software defined self-managing solution for the future network.An autonomic QoS management mechanism in Software Defined Network(AQSDN) is proposed in this paper.In AQSDN,the various QoS features can be configured autonomically in an OpenFlow switch through extending the OpenFlow and OF-Config protocols.Based on AQSDN,a novel packet context-aware QoS model(PCaQoS) is also introduced for improving the network QoS.PCaQoS takes packet context into account when packet is marked and managed into forwarding queues.The implementation of a video application's prototype which evaluates the self-configuration feature of the AQSDN and the enhancement ability of the PCaQoS is presented in order to validate this design. 相似文献
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With the growing trend of deploying Soft-ware defined networks (SDN) in Internet and data centers, it is necessary to investigate the operation of multicast services in this paradigm shift. We propose an OpenFlow-based virtualized platform to support multiple multicast services simultaneously, each with their own customized multicast algorithms and performance-enhancing strate-gies for its service requirements. The contributions include:1) systematic discussions of the technical challenges re-garding to implementing multicast services in SDN, with the proposed architectural components addressing these is-sues; 2) a virtualized platform enabling user-defined multi-cast services, independent of current Internet-based proto-cols; 3) experiments validating the necessity and efficiency of the platform in supporting its design goals and function-alities, with two additional real multicast applications fur-ther confirming the feasibility and operability of the pro-posed prototype. 相似文献
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The integration of 5G networks with cognitive radio (CR) technology enables the software‐defined networking (SDN) infrastructure to support emergency applications. In future, CR can be integrated with 5G and many wireless networks like Wi‐Fi, WSN, and MANET for efficient spectrum utilization with higher data rate and lower latency. This CR technology allows unlicensed users to access the licensed spectrum, whenever it is free. In this paper, an efficient SDN architecture with cognitive ability for emergency network is proposed in which the SDN controller prolong communication between disaster victims and first responders and so the first responders can arrive at the spot directly and rescue the victims. The SDN controller has cognitive ability so that the victims can utilize the vacant licensed band to communicate with the first responders, thereby improving the spectrum utilization of the network. Another two main challenges during emergency are the occurrence of interference and link failure. The proposed dynamic handover algorithm with interference cancellation (DHAIC) cancels the interference between the nodes inside the network and performs dynamic handoff, whenever link failure occurs between the cluster head (CH) and the controller. An optimum throughput and minimal delay is achieved to ensure the network performance. 相似文献
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Recent advances in microelectronics have encouraged the implementation of a wireless sensor network (WSN) in intelligent monitoring systems (IMSs). The IMS for time‐critical applications requires timely and reliable data delivery without sacrificing the energy efficiency of the network. This paper proposes FPS‐MAC, a fuzzy priority scheduling‐based medium access control protocol, designed for event critical traffic in hierarchical WSN. The FPS‐MAC allows time‐critical event traffic to opportunistically steal the data slots allocated for periodic data traffic in event‐based situations. Additionally, a fuzzy logic‐based slot scheduling mechanism is introduced to provide guaranteed and timely medium access to emergency traffic load and ensures the quality‐of‐service (QoS) requirements of IMSs. Both analytical and simulation results for data throughput, energy consumption, and transmission delay of FPS‐MAC, TLHA, E‐BMA, and BMA‐RR have been analyzed to demonstrate the superiority of the proposed FPS‐MAC protocol. 相似文献
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Enzo Fortunato Mario Marchese Maurizio Mongelli Annamaria Raviola 《International Journal of Communication Systems》2004,17(10):935-962
The aim of this paper is to show the effect of the presence of specific management functions within a network that offers quality of service (QoS). The objective is not privileging a particular technology but to highlight the importance to know which control functions a solution may use, which performance limits the functions have and what can be a realistic user expectation. The paper focuses on the meaning of QoS and on the applications requiring quality, then describes QoS solutions including transport technologies, QoS‐oriented technologies, parameters and management functions. In more detail, the effect on QoS provision of the following issues is investigated and discussed concerning the possibility (or not) to aggregate and differentiate traffic, the implementation of call admission control and of traffic filtering to limit flows to their committed rates. Again, the conclusions should not be considered a merit mark about technology, but only an investigation about: what users and customers should expect by the technologies using specific control functions evidencing that the real limitations are not imposed by a specific technology, whose features may be changed and extended, but by the application of control functions that can guarantee requirements' matching. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Liansheng Tan Zhongxun Zhu Wei Zhang Gong Chen 《International Journal of Communication Systems》2014,27(11):2642-2657
Optimization theory and nonlinear programming method have successfully been applied into wire‐lined networks (e.g., the Internet) in developing efficient resource allocation and congestion control schemes. The resource (e.g., bandwidth) allocation in a communication network has been modeled into an optimization problem: the objective is to maximize the source aggregate utility subject to the network resource constraint. However, for wireless networks, how to allocate the resource among the soft quality of service (QoS) traffic remains an important design challenge. Mathematically, the most difficult comes from the non‐concave utility function of soft QoS traffic in the network utility maximization (NUM) problem. Previous result on this problem has only been able to find its sub‐optimal solution. Facing this challenge, this paper establishes some key theorems to find the optimal solution and then present a complete algorithm called utility‐based allocation for soft QoS to obtain the desired optimal solution. The proposed theorems and algorithm act as designing guidelines for resource allocation of soft QoS traffic in a wireless network, which take into account the total available resource of network, the users’ traffic characteristics, and the users’ channel qualities. By numerical examples, we illustrate the explicit solution procedures.Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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针对运用单目标优化算法求解基于 QoS 的 Web 服务选择问题的不足,设计了一种新的 QoS 全局最优Web 服务选择算法.该算法同时优化组合服务的多维 QoS 属性的多个目标函数,并产生 QoS 全局最优的 Pareto 最优解集.首先建立服务选择问题的多目标优化数学模型,然后采用归档式多目标模拟退火设计该算法以优选 Web服务.实验结果表明了该算法是可行的,实现了全局 QoS 最优化的组合服务. 相似文献
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随着虚拟化技术的出现,网络功能虚拟化(Network Function Virtualization,NFV) 和软件定义网络(Software Defined Networking,SDN) 技术使网络功能从硬件中抽象出来并可运行在虚拟机上,将虚拟网络功能映射部署到物理网络上,为用户提供定制化服务。服务功能链(Service Function Chaining,SFC) 由一组虚拟网络功能组成,目前其部署的一个关键问题是如何在保证为用户提供相应服务的同时降低网络资源消耗和负载压力。为此,首先介绍了一种可用于服务功能链编排的NFV 架构,并对基于SRv6 技术的SFC 编排过程进行说明;然后提出了一种有效的SFC动态编排算法——第一步使用广度优先搜索遍历网络并找到部署服务链的最短物理路径,第二步使用蚁群优化算法生成最优部署方案。仿真结果表明,该方案能够有效减轻网络负载,同时平均降低端到端延迟22%,减少带宽资源消耗18%,优化部署成功率23%。 相似文献
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In order to support the quality‐of‐service (QoS) requirements for real‐time traffic over broadband wireless networks, advanced techniques such as space‐time diversity (STD) and multicarrier direct‐sequence code division multiple access (MC‐DS‐CDMA) are implemented at the physical layer. However, the employment of such techniques evidently affects the QoS provisioning algorithms at the medium access control (MAC) layer. In this paper, we propose a space‐time infrastructure and develop a set of cross‐layer real‐time QoS‐provisioning algorithms for admission control, scheduling, and subchannel‐allocations. We analytically map the parameters characterizing the STD onto the admission‐control region guaranteeing the real‐time QoS. Our analytical analyses show that the proposed algorithms can effectively support real‐time QoS provisioning. Also presented are numerical solutions and simulation results showing that the STD can significantly improve the QoS provisioning for real‐time services over wireless networks. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Mobile users expect a network service, in which seamless handoff occurs while moving on a next generation wireless network. In addition, in smart factories (SFs), communication is required between factory floor and manufacturing zone, as well as connectivity towards office IT, or remote production facilities that are connected via wide area network or internet. For this purpose, interworking between heterogeneous networks is important, but there has been little research on global mobility support. Therefore, this paper proposes Proxy‐LMA technology, a mobile IP‐based global internetworking system, to improve global mobility and interoperability in the SFs network environment. The purpose of the proposed Proxy‐LMA system is to support global mobility by using mobility management protocols such as PMIPv6 and MIPv6 in heterogeneous network environment. As a result of the performance evaluation, Proxy‐LMA system is more efficient than other methods in terms of signaling cost and response delay in heterogeneous network environment. Software‐based networking in SFs enables them to easily adapt the communication network to changing requirements. Similar to cloud‐based systems, such SFs could be seen as production clusters that could be rented and configured as needed. The SF network uses software‐defined networking combined with network functions virtualization, to achieve the required flexibility. Despite the fact that the technology is nowadays not yet ready for deployment in today's manufacturing networks, a novel network architecture for SFs based on software‐defined networking and network virtualization is here proposed, to support smart services, especially for Industrie 4.0. 相似文献
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支持话音/数据分组并传的UPMA多址接入协议 总被引：2，自引：0，他引：2
本文提出了一种新的、支持数据/话音业务并传的多址接入协议——根据用户数目妥善安排分组传输的多址接入(User-dependent Perfect-scheduling Multiple Access——UPMA)协议,它根据实际需求对上、下行带宽资源实行动态分配.UPMA协议对不同的业务类型赋予不同的优先级,并用轮询方式妥善地安排节点的分组传输;同时,它采用独特的帧结构,使话音业务总是能够得到优先传输.本文还提出了一种高效的竞争接入算法,以保证激活的节点能够快速接入信道.最后,对UPMA协议的性能进行了仿真并与MPRMA协议的性能进行了比较,结果证明UPMA协议有更好的性能. 相似文献
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Quang‐Dung Ho Mohamed Ashour Tho Le‐Ngoc 《Wireless Communications and Mobile Computing》2011,11(9):1254-1265
This paper studies and develops efficient traffic management techniques for downlink transmission at the base station (BS) of multi‐service IP‐based networks by combining quality‐of‐service (QoS) provision and opportunistic wireless resource allocation. A delay‐margin‐based scheduling (DMS) for downlink traffic flows based on the delays that each packet has experienced up to the BS is proposed. The instantaneous delay margin, represented by the difference between the required and instantaneous delays, quantifies how urgent the packet is, and thus it can determine the queuing priority that should be given to the packet. The proposed DMS is further integrated with the opportunistic scheduling (OPS) to develop various queueing architectures to increase the wireless channel bandwidth efficiency. Different proposed integration approaches are investigated and compared in terms of delay outage probability and wireless channel bandwidth efficiency by simulation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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H. C. Leligou Ch. Linardakis K. Kanonakis J. D. Angelopoulos Th. Orphanoudakis 《International Journal of Communication Systems》2006,19(5):603-617
The steadily rising demand for multimedia and data services, the falling cost and omnipresence of Ethernet and the maturity of passive optical networks (PON) technology, promise to radically change the landscape in the local loop. The heart of a gigabit PON system (recently standardized by FSAN/ITU) is the medium access controller (MAC), which arbitrates access to the upstream link among users with fluctuating traffic demands and effects the multiplexing and concentration policy. At the same time, it has to safeguard the service quality and enforce the parameters agreed in the service level agreements (SLAs) between the users and the service provider. In this paper, a MAC protocol designed to serve any mix of services according to their quality of service (QoS) needs, employing four priority levels along with a high number of logically separate data queues is presented. The architecture and implementation in hardware of a MAC algorithm capable of allocating bandwidth down to a resolution of a byte with QoS differentiation is the focus of this paper. It employs the bandwidth arbitration tools of the FSAN/ITU G.984.3 standard and maps SLA parameters to GPON service parameters to create an efficient, fair and flexible residential access system. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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鉴于软件定义网络（Software Defined Network,SDN）中带外控制方式的代价及成本较高,基于带内连接网络拓扑,提出了一种SDN带内控制连接建立方法。该方法首先通过链路层发现协议（Link Layer Discovery Protocol,LLDP）完成SDN控制器IP分发和SDN交换机IP分配,其中SDN交换机IP分配采用基于可变长子网掩码（Variable Length Subnet Mask,VLSM）的全自动IP分配技术来实现;之后,基于无类别域间路由（Classless Inter domain Routing,CIDR）的路由聚合技术实现带内路由自动构建。实验结果表明,该方法能够实现SDN交换机与SDN控制器带内控制连接的自动建立,减小了SDN网络的配置复杂度和部署难度,同时使SDN交换机路由表条目数量得到控制,降低了带内路由构建的复杂性,为SDN控制平面与转发平面控制信道的建立提供了设计参考。 相似文献
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In ad hoc wireless networks, the high mobility of hosts is usually a major reason for link failures. The general ‘shortest path’ based routing protocols may not lead to stable routes. In this paper, we propose a mobility assessment on‐demand (MAOD) routing protocol to select a stable route in order to enhance system throughput and performance. An error count parameter is used to judge whether a host is highly mobile. The proposed MAOD routing protocol is an on‐demand routing protocol similar to dynamic source routing (DSR). The difference between MAOD and DSR is in the path selection method. Because MAOD takes the mobility of hosts into consideration, it will select a more stable and reliable path than DSR. In comparison, DSR only considers whether this route is a shortest path or not. Finally, the system performance is analyzed by using the global mobile simulation (GloMoSim) simulator. We can observe that MAOD routing protocol outperforms DSR routing protocol especially in the high mobility environment. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Gang Feng 《International Journal of Communication Systems》2007,20(1):9-22
The development of efficient quality of service (QoS) routing algorithms in a high‐speed networking or the next generation IP networking environment is a very important and at the same time very difficult task due to the need to provide divergent services with multiple QoS requirements. Recently, a heuristic algorithm H_MCOP, which is based on a non‐linear Lagrange relaxation (NLR) technique, has been proposed to resolve the contradiction between the time complexity and the quality of solution. Even though H_MCOP has demonstrated outstanding capability of finding feasible solutions to the multi‐path constrained (MCP) problem, it has not exploited the full capability that an NLR‐based technique could offer. In this paper, we propose a new NLR‐based heuristic called NLR_MCP, in which the search process is interpreted from a probability's perspective. Simulation results indicate that NLR_MCP can achieve a higher probability of finding feasible solutions than H_MCOP. We also verify that the performance improvement of a MCP heuristic has a tremendous impact on the performance of a higher level heuristic that uses a MCP heuristic as the basic step. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献