Mobility Support for Content Source in Content-Centric Networking

Content-centric networking(CCN) is rising to solve the problems suffered by traditional networks,especially in terms of content delivery.One of the critical issues for basic CCN is supporting mobility.Handoff of Mobile Content Source(MCS) will result in a large scale routing update,which generates huge amount of routing overhead and leads to service interruption.Most of the existing CCN mobility mechanisms are transplanted from the IP mobility solutions,which are unnaturally integrated with CCN.Different from previous works,a mobility strategy from the perspective of CCN architecture is proposed to support the handoff of MCS in this paper.Especially,we define the critical network routers that can limit the routing update scale effectively when MCS handoff is conducted.Based on the defined critical network routers,the proposed scheme can provide lower routing update overhead,faster routing convergence and shorter service interruption time.Finally,series of simulations are conducted to validate the effectiveness of our proposed scheme.     

Joint multi-QoS and energy saving routing for LEO satellite network

Low earth orbit(LEO) satellite network provides global coverage and supports a wide range of services. However, due to the rapid changes and energy-limitation of satellites, how to meet the demand of the quality of service(QoS) from ground traffic and prolong the lifetime of LEO satellite network is the research emphasis of the investigator. Hence, a routing algorithm which takes into account the multi-QoS requirements and satellite energy consumption(QER) of LEO satellite network is proposed. Firstly, the satellite intimacy degree(SID) and the path health degree(PHD) are introduced to obtain the path evaluation function according to the energy consumption and queue state of the satellite. Then, the distributed routing QER is established through the path evaluation function and the idea of genetic algorithm(GA), which enables each satellite to adjust traffic and realizes the network load balancing. Simulation results show that QER performs well in terms of end-to-end delay, delay jitter, and system throughput.     

Distributed channel assignment combined with routing over multi-radio multi-channel wireless mesh networks

In order to realize the reduction of equipment cost and the demand of higher capacity,wireless mesh network(WMN) router devices usually have several interfaces and work on multi-channels.Jointing channel allocation,interface assignment and routing can efficiently improve the network capacity.This paper presents an efficient channel assignment scheme combined with the multi-radio link quality source routing(MR-LQSR) protocol,which is called channel assignment with MR-LQSR(CA-LQSR).In this scheme,a physical interference model is established:calculated transmission time(CTT) is proposed as the metric of channel assignment,which can reflect the real network environment and channel interference best,and enhanced weighted cumulative expected transmission time(EWCETT) is proposed as the routing metric,which preserves load balancing and bandwidth of links.Meantime,the expression of EWCETT contains the value of CTT,thus the total cost time of channel assignment and routing can be reduced.Simulation results show that our method has advantage of higher throughput,lower end-to-end time delay,and less network cost over some other existing methods.     

Topology and analysis of an N-stage cascaded polymer eight-port microring optical router with 7N channel wavelengths

Eight-port optical routers are widely used in cluster-mesh photonic networks-on-chip(No C). By using 24 groups of cross-coupling two-ring resonators, a 1-stage 8-port polymer optical router is proposed, which can optically route 7 channel wavelength data streams along definite path in two-dimensional(2D) plane. Under the selected 7 channel wavelengths, the insertion losses along all routing paths are within 0.02-0.58 d B, the maximum crosstalk of all routing operations is less than-39 d B, and the device footprint size is about 0.79 mm2. Then, a universal novel structure and routing scheme of N-stage cascaded 8-port optical router are presented, which contains 7N channel wavelengths. Because of the good scalability in wavelength, this device shows potential application of wideband signal routing in optical No C.     

Query routing mismatch alleviation architecture for P2P file lookup in MANETs

A cross-layer optimized query routing mismatch alleviation(QRMA)architecture is proposed to mitigate the problem of query routing mismatch(QRM)phenomenon between the structured peer to peer(P2P)overlay and the routing layer in mobile Ad-hoc networks(MANETs),which is an important issue that results in the inefficiency of lookup process in the system.Explicated with the representative Chord protocol,the proposal exploits the information of topologic neighbors in the routing layer of MANETs to find if there is any optimized alternative next hop in P2P overlay during conventional lookup progress.Once an alternative next hop is detected,it will take the shortcut to accelerate the query procedure and therefore alleviate the QRM problem in scalable MANETs without any assistance of affiliation equipments such as GPS device.The probability of finding out such an alternative node is formulated and the factors that could increase the chance are discussed.The simulation results show that the proposed architecture can effectively alleviate the QRM problem and significantly improve the system performance compared with the conventional mechanism.     

Overlay networking： applications and research challenges

Overlay networking is one of the perspective solutions to today‘s Internet challenges. At basic service level, overlay networks can serve as a supplement and enhancement of existing services, such as routing and addressing. At high application level, overlay networks can be used for applications, which are difficult to deploy in existing IP architecture with some specific reasons, e.g., they need high-level information, which is hard to obtain by underlying layers. To address the heterogeneity of today‘s Internet, overlay networks provide ways to service availability and desirable performance while retaining scalability. In contrast to changing the existing network layer, overlay networks allow bootstrapping, which is most important in the development of Internet infrastructure. Various applications of overlay networking are clarified in this paper. Research challenges including routing and searching in overlay networking are also identified.     

Military multi-hop routing protocol

Military tactical network is one of the most important applications of ad hoc network. Currently the existing routing protocols are put forward based on the simple and universal network model which has the ability of multi-hop routing but cannot work efficiently in the special military applications. The narrow bandwidth and limited energy of the wireless network make general routing protocols seem to be more redundant. In order to satisfy military needs properly, this letter makes a detailed analysis of physical nodes and traffic distribution in military network, uses cross-layer design concept for reference, combines traffic characteristic of application layer with routing protocol design. It categorized routing problem as crucial routes and non-crucial routes which adopted separate maintenance methods. It not only realizes basic transmission function but also works efficiently. It is quite fit for military application.     

Robust multi-path routing for dynamic topology in wireless sensor networks

Wireless sensor networks are being widely researched and are expected to be used in several scenarios. On the leading edge of treads, on-demand, high-reliability, and low-latency routing protocol is desirable for indoor environment applications. This article proposes a routing scheme called robust multi-path routing that establishes and uses multiple node-disjoint routes. Providing multiple routes helps to reduce the route recovery process and control the message overhead. The performance comparison of this protocol with dynamic source routing (DSR) by OPNET simulations shows that this protocol is able to achieve a remarkable improvement in the packet delivery ratio and average end-to-end delay.     

A Secure Adaptive Routing Strategy Using Immune Mechanism in MANET

Many protocols have been proposed to in- crease efficiency and security of traditional protocols in Mobile ad-hoc networks （MANET）, but they are all facing the problem of computation overhead which leads to im- practicability. Adaptive routing strategy （ARS） is a novel routing strategy that switches routing protocol according to the network condition. Though this method alleviates the problem of efficiency, it doesn＇t cover the secure issues. We integrate our security mechanism based on Artificial immune system （AIS）, with adaptive routing strategy to enhance efficiency and security. First we presented a more appropriate definition to the measurement of network con- dition, then we designed a secure adaptive routing strategy based on the definition. At last, we gave a performance analysis to validate the correctness and reliability of our scheme.     

ESMD-Flow: An Intelligent Flow Forwarding Scheme with Endogenous Security Based on Mimic Defense in Space-Air-Ground Integrated Network

The Space-Air-Ground Integrated Network(SAGIN) realizes the integration of space, air,and ground networks, obtaining the global communication coverage.Software-Defined Networking(SDN) architecture in SAGIN has become a promising solution to guarantee the Quality of Service(QoS).However, the current routing algorithms mainly focus on the QoS of the service, rarely considering the security requirement of flow. To realize the secure transmission of flows in SAGIN, we propose an intelligent flow forwarding scheme with endogenous security based on Mimic Defense(ESMD-Flow). In this scheme, SDN controller will evaluate the reliability of nodes and links, isolate malicious nodes based on the reliability evaluation value, and adapt multipath routing strategy to ensure that flows are always forwarded along the most reliable multiple paths. In addition, in order to meet the security requirement of flows, we introduce the programming data plane to design a multiprotocol forwarding strategy for realizing the multiprotocol dynamic forwarding of flows. ESMD-Flow can reduce the network attack surface and improve the secure transmission capability of flows by implementing multipath routing and multi-protocol hybrid forwarding mechanism. The extensive simulations demonstrate that ESMD-Flow can significantly improve the average path reliability for routing and increase the difficulty of network eavesdropping while improving the network throughput and reducing the average packet delay.     

Novel control plane framework and protocol extensions for Spectrum-Efficient Optical Transport Networks

Spectrum-Efficient Optical Transport Networks (SE-OTN), the most important character of which is high spectrum efficiency due to flexible grid, have attracted much attention recently. However, it cannot be employed for practical use since most of the related protocols are immature. This paper mainly focuses on the framework and protocol extensions for the control plane of SE-OTN. A novel control plane framework is designed combining the advantages of Generalized Multi-Protocol Label Switching (GMPLS) and Path Computation Element (PCE), and several routing and spectrum assignment (RSA) models are built. Furthermore, motivation and extension solutions for Open Shortest Path First-Traffic Engineering (OSPF-TE), Resource ReSerVation Protocol-Traffic Engineering (RSVP-TE), and PCE Protocol (PCEP) are proposed based on this framework. An experimental testbed of large-scale spectrum-efficient optical networks with the capability of supporting 1000 GMPLS-based control nodes has been built to validate the performance of the protocols and algorithms, and some numeric results and analysis are given finally. Numeric results show that our proposed Centralized Routing and Centralized Spectrum Assignment (CR+CSA) model has better performance than Centralized Routing and Distributed Spectrum Assignment (CR+DSA) and Distributed Routing and Distributed Spectrum Assignment (DR+DSA), and spectrum defragmentation algorithm based on spectrum compactness can get good performance in the CR+CSA model.     

可变带宽光网络中多项式复杂度的频谱扫描路由算法

Optical Orthogonal Frequency Division Multiplexing (OOFDM) has been proposed as a highly spectrum-efficient modulation technique, which can provide flexible spectrum assignment with fine granularity. In OOFDM-based flexible optical networks, Routing and Spectrum Assignment (RSA) has become a key problem. However, widely used dynamic RSA schemes, such as Fixed Routing (FR) and K-shortest Paths (KSP) routing schemes, are not able to realize route computation based on the link state in-formation, thus leading to poor blocking performance and inefficient resource utilization. To solve this problem, Adaptive Routing (AR) schemes, e.g., the Entire Path Searching (EPS) scheme, have been proposed recently. These schemes have low blocking probability; however, since their computational complexities are factorial, they are not suitable for use in real networks. In this paper, we propose a novel Spectrum-Scan Routing (SSR) scheme in dynamic flexible optical networks. To the best of our knowledge, SSR is the first polynomial-time AR scheme that can realize adaptive shortest-route computation. Simulation results show that our proposed SSR scheme has lower blocking probability and higher resource utilization compared with FR and EPS. Moreover, the worst-case computational complexity of SSR increases linearly with the network scale of the torus topologies, making it applicable to real networks.     

MICRON—A Framework for Connection Establishment in Optical Networks

Traffic grooming in optical networks has gained significance due to the prevailing sub-wavelength requirement of end users. Optical networks get upgraded to the latest technology slowly with time with only a subset of nodes being upgraded to the latest technology. The networks are thus comprised of nodes employing heterogeneous switching architectures. In this paper, we develop a framework called Methodology for Information Collection and Routing in Optical Networks (MICRON) for connection establishment in optical grooming networks with heterogeneous switching architectures. We illustrate with examples the information that may be collected from the links, and operators that may be used to obtain information along a path. The information can be used to select a path dynamically depending on the network status. We complete the MICRON framework by providing a generic channel assignment procedure that could be employed to implement different channel assignment schemes. Various routing and channel assignment algorithms can be developed from the proposed framework. The framework may be easily implemented with simple traffic engineering extensions to the already existing routing protocols in the wide-area networks.     

Demonstration of Deflection Routing With Layer-2 Evaluation at 40 Gb/s in a Three-Node Optical Burst Switching Testbed

We developed an optical burst switching (OBS) network testbed with three nodes, where each node consisted of a fast 5 5 (Pb,La)(Zr,Ti)O optical matrix switch. A newly developed Ether frame media converter was successfully used to evaluate Layer-2 performance of the testbed, with a line rate of 40Gb/s. A dynamic deflection routing scheme for contention resolution is implemented. Error-free switching with 40-Gb/s payload was achieved over the three nodes, promising low frame loss due to dynamic operation. By comparing effects of random collision with and without deflection routing for varying loads, we demonstrate that near-theoretical low frame loss is achievable in fast Layer-2 (Ether frame) transport over OBS networks.     

Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.     

基于博弈理论的无线传感器网络分布式节能路由算法

为了有效解决无线传感器网络路由节能问题,该文提出适合无线传感器网络的节能路由算法。在引入博弈理论概念建立网络模型的基础上,通过对于以往传感器网络簇首选择方法的研究,设计了一种基于博弈论的,兼顾节点剩余能量及簇首分布的节能路由DEER(DistributedEnergy-EconomicalRouting),大大节省了分布式决策网络协议的能量损耗。仿真证明了该方法在无线传感器网络中,能够有效地平衡网络负载,节省节点能量,延长网络寿命。     

Adaptive alternate routing in WDM networks and its performance tradeoffs in the presence of wavelength converters

Routing in wavelength-routed all-optical WDM networks has received much attention in the past decade, for which fixed and dynamic routing methods have been proposed. Taking into account the observation that wavelength-routed all-optical WDM networks are similar to circuit-switched voice networks, except with regard to wavelength conversion, we propose an adaptive alternate routing (AAR) scheme for wavelength-routed all-optical WDM networks. A major benefit of AAR is that it can operate and adapt without requiring an exchange of network status, i.e., it is an information-less adaptive routing scheme. The scope of this work is to understand this scheme in its own right since no other dynamic routing schemes are known to have the information-less property. In this paper, we conduct a systematic study of AAR with regard to factors such as the number of converters, load conditions, traffic patterns, network topologies, and the number of alternate paths considered. We observe that the routing scheme with multiple alternate routes provides more gain at a lower load instead of requiring any nodes to be equipped with wavelength converters. On the other hand, the availability of wavelength converters at some nodes, along with adaptive routing, is beneficial at a moderate to high load without requiring all nodes to be equipped with wavelength converters. We also observed that a small number of alternate routes considered in a network without wavelength converters gives a much better performance than a network with full wavelength converters and fewer alternate routes. Throughout this study, we observed that the proposed adaptive alternate routing scheme adapts well to the network traffic condition.     

MR2-GRADE:一种基于梯度值的无线传感器网络高能效多径干扰避免路由协议

无线传感器网络的径间干扰是多径路由亟待解决的重要问题,然而目前干扰避免策略的设计忽略了无线传感器网络最关心的能耗问题.本文提出基于梯度的MR2-GRADE路由协议框架,利用已建路径上各节点到目的节点的跳数构造干扰范围外节点的网络梯度,有效避免传统广播方式的高路由开销.针对基于梯度的局部路由决策导致后续路径创建成功率受网络节点分布密度影响较大的问题,设计了基于梯度的贪婪转发算法GRADE_GF和受限泛洪算法GRADE_RF.仿真实验结果表明:与已有的同类多径干扰避免路由相比,基于MR2-GRADE协议框架的路由可有效降低路由开销,随着网络规模扩大,优势越明显.     

A technique to improve network lifetime in mobile ad hoc networks

Energy is an important issue in mobile ad hoc networks (MANETs), and different energy‐aware routing mechanisms have been proposed to minimize the energy consumption in MANETs. Most of the energy‐aware routing schemes reported in the literature have considered only the residual battery capacity as the cost metric in computing a path. In this paper, we have proposed, an energy‐aware routing technique which considers the following parameters: (i) a cost metric, which is a function of residual battery power and energy consumption rate of participating nodes in path computation; (ii) a variable transmission power technique for transmitting data packets; and (iii) To minimize the over‐utilization of participating nodes, a limit is set on the number of paths that can be established to a destination through a participating node. The proposed scheme is simulated using Qualnet 4.5 simulator, and compared with Ad hoc On‐Demand Distance Vector (AODV) and Lifetime Enhancement Routing (LER). We observed that the proposed scheme performs better in terms of network lifetime and energy consumption. Copyright © 2014 John Wiley & Sons, Ltd.     

A novel self-routing address scheme for all-optical packet-switched networks with arbitrary topologies

Pure all-optical packet-switched networks in which both header processing and packet routing are carried out in the optical domain overcome the bandwidth bottlenecks of optoelectronic conversions and therefore are expected to meet the needs of next generation high speed networks. Due to the limited capabilities of available optical logic devices, realizations of pure all-optical packet-switched networks in the near future will likely employ routing schemes that minimize the complexity of routing control. In this paper, we propose a novel self-routing scheme that identifies the output ports of the nodes in a network instead of the nodes themselves. The proposed address scheme requires single bit processing only and is applicable to small to medium size pure all-optical packet-switched networks with arbitrary topologies. Unlike traditional self-routing schemes, multiple paths between two nodes can be defined. An hierarchical address structure can be used in the proposed routing scheme to shorten the address.