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 ...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.展开更多
In order to discover more detailed topol- ogy inforrmtion of a certain network, a fightweight approach is proposed, in which only one probe source is required. In this approach, a heuristic method in using the＂ trace...In order to discover more detailed topol- ogy inforrmtion of a certain network, a fightweight approach is proposed, in which only one probe source is required. In this approach, a heuristic method in using the＂ traceroute＂ tool is introduced to collect more topology pieces. Based on those traces, subnets （or point-to-point links） in the backbone can be identified. With those identified inforrmtion, a set of roles is developed to resolve router IP aliases. Experiments with both this ap- proach and existing topology discovery methods are carried out on two real networks, i.e., TUNET, the Tsinghua University campus network, and CERNET （AS4538）, the third largest ISP network of China. According to the comparison, the approach in this paper can get nmch higher quality inforrm-tion about 1P addresses, links, and touters. In con-clusion, a more complete and accurate topology can be gained with this approach.展开更多
Through the analysis of network topology discovery algorithm used ICMP protocol and FDB address, a novel layer topology discovery and link layer topology discovery algorithm which is suitable for campus network enviro...Through the analysis of network topology discovery algorithm used ICMP protocol and FDB address, a novel layer topology discovery and link layer topology discovery algorithm which is suitable for campus network environment is proposed based on SNMP protocol. This algorithm can rapidly and accurately calculate the second and third floors topology of the whole pipe network.展开更多
Community discovery of complex networks,esp.of social networks,has been a hotly debated topic in academic circles in recent years.Since actual networks usually contain some overlapping nodes that are difficult to assi...Community discovery of complex networks,esp.of social networks,has been a hotly debated topic in academic circles in recent years.Since actual networks usually contain some overlapping nodes that are difficult to assign to a certain community,overlapping community discovery is under great demand in practical applications.However,at present network community discovery is mainly done by non-overlapping community discovery methods,overlapping discovery methods are not common.In this context,an overlapping community discovery method is proposed hereby based on topological potential and specific algorithms are also provided.This method not only considers the spread of the uncertainty of community identity of the overlapping nodes in the network,but also realizes a quantified representation,i.e.,uncertainty measure,of the community identity of the overlapping nodes.The experiment results show that this method yields the results that are consistent with those by the classic methods and are more reasonable.展开更多
The research and analysis of Internet topology is hot in the field of networkmeasurement, which have important applications in network security, traffic schedulingand many other fields. Most of the existing works are ...The research and analysis of Internet topology is hot in the field of networkmeasurement, which have important applications in network security, traffic schedulingand many other fields. Most of the existing works are focused on the AS-level and routerleveltopology, but few works are about the IP-level topology. In fact, obtaining thetopology of each continent and knowing how the topologies of the continents areconnected to each other can help us understanding the Internet around the world morethoroughly. In this paper, we obtained data sets from RIPE, constructed and analyzednetwork topologies of all the continents. By analyzing the topological connectionsbetween continents, we found out that most of the junctions of inter-continent traces arelocated in a few countries.展开更多
After the discovery of fraction quantum Hall states in the 1980s, it became more and more clear that Landau symmetry breaking theory does not describe all possible quantum phases of matter. The new quan- tum phases of...After the discovery of fraction quantum Hall states in the 1980s, it became more and more clear that Landau symmetry breaking theory does not describe all possible quantum phases of matter. The new quan- tum phases of matter were called topologically ordered phases（for gapped cases） or quantum ordered phases （for gapless cases）, which correspond to pat- terns of many-body entanglement. One may won- der： besides quantum Hall systems, are there other systems that realize the new topological/quantum order？展开更多
针对目前传统机动通信系统、主流软件定义网络(software defined network,SDN)的拓扑发现方法不适合基于分布式SDN的机动通信系统这一问题,遵循OpenFlow拓扑发现算法(OpenFlow discovery protocol,OFDP)移植传输控制协议/网际协议(trans...针对目前传统机动通信系统、主流软件定义网络(software defined network,SDN)的拓扑发现方法不适合基于分布式SDN的机动通信系统这一问题,遵循OpenFlow拓扑发现算法(OpenFlow discovery protocol,OFDP)移植传输控制协议/网际协议(transmission control protocol/Internet protocol,TCP/IP)相关协议到SDN网络的研究思路,对开放最短路径优先(open shortest path first,OSPF)协议进行优化,精简协议状态机、优化协议报文、增加协议功能并设计拓扑发现算法,提出一种适合基于分布式SDN的机动通信系统的拓扑发现方法,并搭建仿真实验平台进行验证。实验结果表明,优化后OSPF协议适应于分布式SDN网络,网络拓扑建链时间降低80%且重新收敛时间显著降低,建链开销平均每秒接收字节数、发送字节数分别下降了31.7%和21.5%,维持开销平均每秒收发字节数降低了45%,增加了收集信道种类等网络信息的新功能。展开更多
IP geolocation determines geographical location by the IP address of Internet hosts.IP geolocation is widely used by target advertising,online fraud detection,cyber-attacks attribution and so on.It has gained much mor...IP geolocation determines geographical location by the IP address of Internet hosts.IP geolocation is widely used by target advertising,online fraud detection,cyber-attacks attribution and so on.It has gained much more attentions in these years since more and more physical devices are connected to cyberspace.Most geolocation methods cannot resolve the geolocation accuracy for those devices with few landmarks around.In this paper,we propose a novel geolocation approach that is based on common routers as secondary landmarks(Common Routers-based Geolocation,CRG).We search plenty of common routers by topology discovery among web server landmarks.We use statistical learning to study localized(delay,hop)-distance correlation and locate these common routers.We locate the accurate positions of common routers and convert them as secondary landmarks to help improve the feasibility of our geolocation system in areas that landmarks are sparsely distributed.We manage to improve the geolocation accuracy and decrease the maximum geolocation error compared to one of the state-of-the-art geolocation methods.At the end of this paper,we discuss the reason of the efficiency of our method and our future research.展开更多
IP geolocation determines geographical location by the IP address of Internet hosts.IP geolocation is widely used by target advertising,online fraud detection,cyber-attacks attribution and so on.It has gained much mor...IP geolocation determines geographical location by the IP address of Internet hosts.IP geolocation is widely used by target advertising,online fraud detection,cyber-attacks attribution and so on.It has gained much more attentions in these years since more and more physical devices are connected to cyberspace.Most geolocation methods cannot resolve the geolocation accuracy for those devices with few landmarks around.In this paper,we propose a novel geolocation approach that is based on common routers as secondary landmarks(Common Routers-based Geolocation,CRG).We search plenty of common routers by topology discovery among web server landmarks.We use statistical learning to study localized(delay,hop)-distance correlation and locate these common routers.We locate the accurate positions of common routers and convert them as secondary landmarks to help improve the feasibility of our geolocation system in areas that landmarks are sparsely distributed.We manage to improve the geolocation accuracy and decrease the maximum geolocation error compared to one of the state-of-the-art geolocation methods.At the end of this paper,we discuss the reason of the efficiency of our method and our future research.展开更多
基金supported by State Key Program of National Natural Science of China (91738202)Science &Technology Program of Beijing (Z171100005217001)
文摘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.
基金This paper was supported by the National Natural Science Foundation of China under Grant No. 60973144 the National Basic Research Program of China under Grant No. 2009CB320505.
文摘In order to discover more detailed topol- ogy inforrmtion of a certain network, a fightweight approach is proposed, in which only one probe source is required. In this approach, a heuristic method in using the＂ traceroute＂ tool is introduced to collect more topology pieces. Based on those traces, subnets （or point-to-point links） in the backbone can be identified. With those identified inforrmtion, a set of roles is developed to resolve router IP aliases. Experiments with both this ap- proach and existing topology discovery methods are carried out on two real networks, i.e., TUNET, the Tsinghua University campus network, and CERNET （AS4538）, the third largest ISP network of China. According to the comparison, the approach in this paper can get nmch higher quality inforrm-tion about 1P addresses, links, and touters. In con-clusion, a more complete and accurate topology can be gained with this approach.
文摘Through the analysis of network topology discovery algorithm used ICMP protocol and FDB address, a novel layer topology discovery and link layer topology discovery algorithm which is suitable for campus network environment is proposed based on SNMP protocol. This algorithm can rapidly and accurately calculate the second and third floors topology of the whole pipe network.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61073041,60873037,61100008 and 61073043)the Natural Science Foundation of Heilongjiang Province(Grant No.F200901 and F201023)+1 种基金the Harbin Special Funds for Technological Innovation Research(Grant No. 2010RFXXG002 and 2011RFXXG015)the Fundamental Research Funds for the Central Universities of China(Grant No.HEUCF100602)
文摘Community discovery of complex networks,esp.of social networks,has been a hotly debated topic in academic circles in recent years.Since actual networks usually contain some overlapping nodes that are difficult to assign to a certain community,overlapping community discovery is under great demand in practical applications.However,at present network community discovery is mainly done by non-overlapping community discovery methods,overlapping discovery methods are not common.In this context,an overlapping community discovery method is proposed hereby based on topological potential and specific algorithms are also provided.This method not only considers the spread of the uncertainty of community identity of the overlapping nodes in the network,but also realizes a quantified representation,i.e.,uncertainty measure,of the community identity of the overlapping nodes.The experiment results show that this method yields the results that are consistent with those by the classic methods and are more reasonable.
文摘The research and analysis of Internet topology is hot in the field of networkmeasurement, which have important applications in network security, traffic schedulingand many other fields. Most of the existing works are focused on the AS-level and routerleveltopology, but few works are about the IP-level topology. In fact, obtaining thetopology of each continent and knowing how the topologies of the continents areconnected to each other can help us understanding the Internet around the world morethoroughly. In this paper, we obtained data sets from RIPE, constructed and analyzednetwork topologies of all the continents. By analyzing the topological connectionsbetween continents, we found out that most of the junctions of inter-continent traces arelocated in a few countries.
文摘After the discovery of fraction quantum Hall states in the 1980s, it became more and more clear that Landau symmetry breaking theory does not describe all possible quantum phases of matter. The new quan- tum phases of matter were called topologically ordered phases（for gapped cases） or quantum ordered phases （for gapless cases）, which correspond to pat- terns of many-body entanglement. One may won- der： besides quantum Hall systems, are there other systems that realize the new topological/quantum order？
文摘IP geolocation determines geographical location by the IP address of Internet hosts.IP geolocation is widely used by target advertising,online fraud detection,cyber-attacks attribution and so on.It has gained much more attentions in these years since more and more physical devices are connected to cyberspace.Most geolocation methods cannot resolve the geolocation accuracy for those devices with few landmarks around.In this paper,we propose a novel geolocation approach that is based on common routers as secondary landmarks(Common Routers-based Geolocation,CRG).We search plenty of common routers by topology discovery among web server landmarks.We use statistical learning to study localized(delay,hop)-distance correlation and locate these common routers.We locate the accurate positions of common routers and convert them as secondary landmarks to help improve the feasibility of our geolocation system in areas that landmarks are sparsely distributed.We manage to improve the geolocation accuracy and decrease the maximum geolocation error compared to one of the state-of-the-art geolocation methods.At the end of this paper,we discuss the reason of the efficiency of our method and our future research.
文摘IP geolocation determines geographical location by the IP address of Internet hosts.IP geolocation is widely used by target advertising,online fraud detection,cyber-attacks attribution and so on.It has gained much more attentions in these years since more and more physical devices are connected to cyberspace.Most geolocation methods cannot resolve the geolocation accuracy for those devices with few landmarks around.In this paper,we propose a novel geolocation approach that is based on common routers as secondary landmarks(Common Routers-based Geolocation,CRG).We search plenty of common routers by topology discovery among web server landmarks.We use statistical learning to study localized(delay,hop)-distance correlation and locate these common routers.We locate the accurate positions of common routers and convert them as secondary landmarks to help improve the feasibility of our geolocation system in areas that landmarks are sparsely distributed.We manage to improve the geolocation accuracy and decrease the maximum geolocation error compared to one of the state-of-the-art geolocation methods.At the end of this paper,we discuss the reason of the efficiency of our method and our future research.
