Topology Discovery Sub-Layer for Integrated Terrestrial-Satellite Network Routing Schemes

With the booming development of terrestrial network, scaling terrestrial network over satellite network to build Integrated Terrestrial-Satellite Network(ITSN) and meanwhile to provide the global Internet access, has become ever more attractive. Naturally, the widely and successfully used terrestrial routing protocols are the promising protocols to integrate the terrestrial and satellite networks. However, the terrestrial routing protocols, which rely on propagating routing messages to discover New Network Topology(NNT) in the terrestrial network with rare topology changes, will suffer from overly numerous routing messages in satellite network whose topology frequently changes as satellites move. In this paper, a Topology Discovery Sub-layer for ITSN Routing Schemes(TDS-IRS) is firstly proposed to avoid the propagation of numerous routing messages by taking advantage of the movement predictability of satellite and the requirements of routing schemes to discover NNT in advance of topology change. Secondly, a Weighted Perfect Matching based Topology Discovery(WPM-TD) model is designed to conduct the NNT discovery on the ground. Thirdly, this paper builds a testbed with real network devices and meanwhile interconnect that testbed with real Internet, to validate that RS-TDS can discover NNT immediately with the less on-board overhead compared with optimized routing schemes. Finally, different network scenarios are applied to validate the WPM-TD, i.e., the core module of TDS-IRS. Extensive experiments show WPM-TD can work efficiently, avoiding the invalid NNT discovery and decreasing 20% ~ 57% of potential topology changes, which can also improve up to 47% ~ 105% of network throughput.

Adaptive clustering hierarchy routing for delay tolerant network

Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combination of single copy scheme and multi-copy scheme and the combination of hop-by-hop and multi-hop mechanism ACHR,which has the advantages in simplicity,availability and well-expansibility.The result shows that it can take advantage of the random communication opportunities and local network connectivity,and achieves 1.6 times delivery ratio and 60% overhead compared with its counterpart.

Interruption Tolerance Routing Strategy for Space Information Network

Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will consume considerable time(compared with ground networks)derived from long ISL delay and flooding between hundreds or even thousands of satellites.During the network convergence/update stage,the lack of up-to-date forwarding information may cause severe packet loss.Considering the fact that ISL handovers for close-to-earth constellation are predictable and all the ISL handover information could be stored in each satellite during the network initialization,we propose a self-update routing scheme based on open shortest path first(OSPF-SUR)to address the slow route convergence problem caused by frequent ISL handovers.First,for predictable ISL handovers,forwarding tables are updated according to locally stored ISL handover information without link state advertisement(LSA)flooding.Second,for unexpected ISL failures,flooding could be triggered to complete route convergence.In this manner,network convergence time is radically descended by avoiding unnecessary LSA flooding for predictable ISL handovers.Simulation results show that the average packet loss rate caused by ISL handovers is reduced by 90.5%and 61.3%compared with standard OSPF(with three Hello packets confirmation)and OSPF based on interface state(without three Hello packets confirmation),respectively,during a period of topology handover.And the average endto-end delay is also decreased by 47.6%,9.6%,respectively.The packet loss rate of the proposed OSPF-SUR does not change along with the increase of the frequency of topology handovers.

HHR:Hierarchical Hybrid Routing Scheme for Information-Centric Network

Publish/subscribe(pub/sub) paradigm is the main communication model for Information-Centric Network(ICN) proposals.A key issue for pub/sub system is how to route the content objects to the correct subscribers,and ICN is no exception.ICN network would be divided into core domain and many edge domains as today's internet does.HHR(Hierarchy Hybrid Routing scheme) is presented for ICN:A Chord-like routing scheme is used in core domain,while edge domains routing structure can be classified into three categories,Local Routing(LR),Delivery of Local Publication to Core domain(DLPC),and Remote Publication Routing into edge domain(RPR).LR can be decided by each edge domain,which determined by many factors,such as locality characteristic for pub/sub information and local policies.A hierarchical routing algorithm is proposed to solve DLPC and RPR simultaneously.Simulation results demonstrate that HHR can be fast deployed,and can be applied in large scale network or dynamic subscription environment.

Improvisation of Node Mobility Using Cluster Routing-based Group Adaptive in MANET

In today's Internet routing infrastructure,designers have addressed scal-ing concerns in routing constrained multiobjective optimization problems examining latency and mobility concerns as a secondary constrain.In tactical Mobile Ad-hoc Network(MANET),hubs can function based on the work plan in various social affairs and the internally connected hubs are almost having the related moving standards where the topology between one and the other are tightly coupled in steady support by considering the touchstone of hubs such as a self-sorted out,self-mending and self-administration.Clustering in the routing process is one of the key aspects to increase MANET performance by coordinat-ing the pathways using multiple criteria and analytics.We present a Group Adaptive Hybrid Routing Algorithm(GAHRA)for gathering portability,which pursues table-driven directing methodology in stable accumulations and on-request steering strategy for versatile situations.Based on this aspect,the research demonstrates an adjustable framework for commuting between the table-driven approach and the on-request approach,with the objectives of enhancing the out-put of MANET routing computation in each hub.Simulation analysis and replication results reveal that the proposed method is promising than a single well-known existing routing approach and is well-suited for sensitive MANET applications.

A geographic routing protocol based on trunk line in VANETs

A Trunk Line Based Geographic Routing(TLBGR)protocol in Vehicular Ad-hoc Networks(VANETs)is proposed in this paper to solve the problem of data acquisition in the traditional trunk coordinated control system.Because of the characteristics of short communication time and high packet loss among vehicles,the vehicles entering the trunk lines can not transmit their information to the trunk coordinated control system stably.To resolve this problem,the proposed protocol uses the trunk lines’traffic flow and the surrounding road network to provide a real-time data transmission routing scheme.It takes into account the data congestion problem caused by the large traffic flow of the main roads,which leads to the corresponding increase of the information flow of the section and the package loss,and the link partition problem caused by the insufficient traffic flow,which makes the vehicles have to carry and relay information thus increasing the transmission delay.The proposed TLBGR protocol can be divided into two stages:the next-intersection selection,and the next-hop selection in the chosen path between the current and next intersections.Simulation results show that,compared with other IoT routing protocols including Greedy Perimeter Stateless Routing(GPSR),Ad-hoc On Demand Vector(AODV),and Q-AODV,the TLBGR protocol has better performance in aspects of end-to-end delay,delivery rate,and routing cost under the scenario of urban traffic trunk lines.The TLBGR protocol can effectively avoid data congestion and local optimum problems,increase the delivery rate of data packets,and is therefore suitable for the routing requirements in this application scenario.

Potential field based hole detour routing algorithm in wireless sensor networks

The current geographic routing protocols arise data congestion if a multi-flow bypasses a hole simultaneously and excessive energy consumption of hole boundary nodes because these protocols tend to route data packets along the boundaries of void areas （holes） by perimeter routing scheme.This scheme possibly enlarges the holes phenomenon （called hole diffusion problem） and shortens the life span of the network. A novel geographical routing algorithm based on a potential field approach （PFA） is proposed to deal with multiple holes scenario and restrict data to forward near boundary of a hole. That is, data packets are attracted to its sink and are repulsed away from the hole （s）. Simulation results show that PFA is superior to other protocols in terms of packet delivery ratio, network lifetime.

Reliable Data Collection Model and Transmission Framework in Large-Scale Wireless Medical Sensor Networks

Large-scale wireless sensor networks(WSNs)play a critical role in monitoring dangerous scenarios and responding to medical emergencies.However,the inherent instability and error-prone nature of wireless links present significant challenges,necessitating efficient data collection and reliable transmission services.This paper addresses the limitations of existing data transmission and recovery protocols by proposing a systematic end-to-end design tailored for medical event-driven cluster-based large-scale WSNs.The primary goal is to enhance the reliability of data collection and transmission services,ensuring a comprehensive and practical approach.Our approach focuses on refining the hop-count-based routing scheme to achieve fairness in forwarding reliability.Additionally,it emphasizes reliable data collection within clusters and establishes robust data transmission over multiple hops.These systematic improvements are designed to optimize the overall performance of the WSN in real-world scenarios.Simulation results of the proposed protocol validate its exceptional performance compared to other prominent data transmission schemes.The evaluation spans varying sensor densities,wireless channel conditions,and packet transmission rates,showcasing the protocol’s superiority in ensuring reliable and efficient data transfer.Our systematic end-to-end design successfully addresses the challenges posed by the instability of wireless links in large-scaleWSNs.By prioritizing fairness,reliability,and efficiency,the proposed protocol demonstrates its efficacy in enhancing data collection and transmission services,thereby offering a valuable contribution to the field of medical event-drivenWSNs.

OpenFIow-Based Control Architecture for the Mobile FreeSpace Optical Networks

Mobile free space optical networks have aroused much attention due to the ability of providing high speed connectivity over long distance using the wireless laser links,while requiring relatively high available bandwidth resource and less energy consumption.However,maintaining the network with laserlinks is quite challenging due to a number of issues,such as the link fragility,the difficulty in pointingand tracking of the link,which also raises the great difficulty in the control of the network.In this paper,we present the methodology for the deployment of the mobile freespace optical networks based on our proposed OpenFlow-based control architecture.In addition,a new routing scheme is proposed and demonstrated on the testbed based on this control architecture.Delivery ratio,average delivery delay and time complexity are given to verify the performance of the OpenFlow-based control architecture.

APPLICATION OF ID-BASED AGGREGATE SIGNATURE IN MANETS

Aggregate signatures are a useful primitive which allows aggregating many signatures on different messages computed by different users into a single and constant-length signature and adapts to Mobile Ad hoc NETwork (MANETs) very much. Jumin Song, et al. presented an ID-based aggregate signature, applied it to MANETs and proposed a secure routing scheme. In this work, we analyze Jumin Song, et al.’s aggregate signature scheme and find some limitations on its batch verification. In addition, in this work, we apply Craig Gentry, et al.’s ID-based aggregate signature to on-demand routing pro-tocol to present a secure routing scheme. Our scheme not only provides sound authentication and a secure routing protocol in ad hoc networks, but also meets the nature of MANETs.

Estimating minimum ecological water required of the western route first stage project of China＇s south-to-north water transfer scheme for water exporting rivers

It is well known that there is abundant water resources in basin of the Yangtze River, the first largest river in China, which is mainly located in Southern China. However, water resources is very scarce in the basin of the Yellow River, which is mainly located in Northern China. So the western route project of south-north water transfer scheme （WRP-SNWTS） aims to transfer water from the Yangtze River to the Yellow River. The area of WRP-SNWT, located in the upper reaches of the Yangtze River and the main areas of Sichuan and the marginal areas of the Qinghai-Tibet Plateau, has sufficient water resources but fragile ecology and environment. Therefore, it is necessary for WRP-SNWT to analyze the ecology water required. Based on the planning principles of from low elevation to high elevation, from small to large, from short to long and from easy to difficulty, the WRP-SNWT will be constructed through three stage projects. The western route first stage project of the south-north water transfer scheme （WRFST-SNWTS） is planned to transfer 4×10^9m^3/a from six tributaries of the Yalong river and from Dadu river to Jiaqu of Yellow River.. Daqu river and Niqu river are the branches of Xianshui river. Sequ river, Duke river, Make river and Ake river are the branches of Dadu river, which account for 65-70% of the total river run-off. It need more research and the rest run-off can satisfy channel ecology water required. According to analysis ecological water required which mainly satisfy for aquicolous biology in water-exporting region, such as low air temperature. Fish and aquicolous biology main living from May to August, and rivers are iced up from December to March of next year, ecology water required mainly for fish and aquicolous biology. The flow criterion of Tennant method is modified. The ecology water required of WRFSP-SNWTS is estimated by the flow data of Zhuwo gauging station, Zhuba gauging station, Chuosijia gauging station and Zumuzu gauging station. The result show that the ecology water required calculated by modified Tennant less 1 l percent than that of Tennant. This estimating result can supply more water resources for transferring to Yellow River. Meanwhile, this can supply gist for research transferring water of WRFSP-SNWTS.

A compass time-space model-based virtual IP routing scheme for NTSN satellite constellations

Recently,Non-Terrestrial Satellite Networks(NTSTs)have gained more and more attentions due to global coverage,low latency,and high-speed communications.The routing scheme is one of the primary challenges for NTSNs,due to the mega scale of an NTSN constellation and the dynamic topology feature.To solve many pressing problems,a Compass time-space Model-based Virtual IP(CMVIP)routing scheme is proposed in this paper.In order to compensate for discontinuities in existing topology models,a compass-shaped time-space model is proposed.It can be adapted with Inter-Satellite-Link(ISL)and Ground-Satellite-Link(GSL)transmissions.A distributed algorithm with multiple optimization objectives and multiple constraints is applied for routing path discovery.To more realistically verify the specific scheme,a traffic model that supports two different services is proposed.Access and bearer services are the two main applications of an NTSN.Experimental results demonstrate that the proposed scheme achieves superior Qualityof-Service(QoS)performance.In addition,comparison results demonstrate that the CMVIP routing scheme is superior to the Virtual-Topology-based Shortest Path(VT-SP)routing algorithm.

A Fault-Tolerant Routing Scheme in Dynamic Networks

In dynamic networks, links and nodes will be deleted or added regularly. It is very essential for the routing scheme to have the ability of fault-tolerance. The method to achieve such a goal is to generate more than one path for a given set of source and destination. In this paper, the idea of interval routing is used to construct a new scheme (Multi-Node Label Interval Routing scheme, or MNLIR scheme) to realize fault-tolerance. Interval routing is a space-efficient routing method for networks, but the method is static and determinative, and it cannot realize faulttolerance. In MNLIR scheme some nodes will have more than one label, thus some pairs of destination and source will have more than one path; the pairs of nodes, which have inheritance relation, will have the shortest path. Using this character, MNLIR scheme has better overall routing performance than the former interval routing scheme, which can be proven by simulations. The common problem concerning the insertion and deletion of nodes and links is considered in this paper. So if the networks have some changes in topology, MNLIR scheme may find alternative path for certain pairs of nodes. In this way, fault-tolerance can be realized with only a little space added to store the multi-node labels.

Valiant load-balancing and regionalized routing scheme

Valiant load-balancing （VLB） routing scheme has drawbacks of logical full mesh, intermediate nodes （networks） and single application of topology. To address these, the authors propose a novel routing scheme called regionalized VLB （R-VLB）. Based on ideas of VLB and regionalizing, R-VLB divides the nodes of backbone network into several regions whose topological structure is logical full mesh, and combines shortest-path routing scheme and VLB routing scheme. R-VLB also achieves logical local interconnection, non-central nodes （networks） and a wide range of application of topology. The relevant theoretical analysis and simulation results show that R-VLB achieve good throughput and failure performance close to that of VLB, and it even has better delay performance. R-VLB provides an idea for the application of VLB routing scheme.