在移动社交网络中,人们通过携带无线设备在近距离范围内彼此传递信息,从而达到信息的传播。由于移动社交网络中一般不存在端到端的连接,使得数据转发算法成为一个重要问题。文章从社区和节点的社会属性角度,利用社区和节点的影响力,提...在移动社交网络中,人们通过携带无线设备在近距离范围内彼此传递信息,从而达到信息的传播。由于移动社交网络中一般不存在端到端的连接,使得数据转发算法成为一个重要问题。文章从社区和节点的社会属性角度,利用社区和节点的影响力,提出了一种基于影响力的数据转发算法(data forwarding algorithm based on impact,DFAI)。在该算法中,携带数据包的节点只有在遇到影响力达到一定要求的节点时,才拷贝数据包给相遇节点。仿真试验结果显示,与经典的Epidemic和Label算法相比,DFAI可以明显降低网络开销,同时接近Epidemic算法达到的最大传递率。展开更多
命名数据网(named data networking,NDN)作为一种新型的互联网架构,旨在应对日益增长的数据流量。基于其消费者驱动的内容检索模型,NDN自然地支持消费者移动性。然而生产者移动性仍然是一个具有挑战性的问题,需要额外的机制来提高生产...命名数据网(named data networking,NDN)作为一种新型的互联网架构,旨在应对日益增长的数据流量。基于其消费者驱动的内容检索模型,NDN自然地支持消费者移动性。然而生产者移动性仍然是一个具有挑战性的问题,需要额外的机制来提高生产者移动期间的数据可用性。针对该问题,提出一种可扩展的移动管理机制来支持生产者移动性。该机制利用网络终端在基于名称的NDN转发平面上建立了临时转发路径,并设计了缓存与重传机制支持时延容忍和时延敏感的应用数据流。最后在ndnSIM中建立了一个全面的仿真环境,对所提方案与现有解决方案进行了评估和比较。仿真结果表明,该机制能够充分支持生产者移动性。当速度为30 m/s时,丢包率仅为3.0%,平均传输延时为352.1 ms。此外,支持生产者移动性所需的额外消耗对于方案相比降低了49.18%。展开更多
During convergence,after a link state change in traditional networks with a distributed control plane,packets may get caught in transient forwarding loops.Such loops can be avoided by imposing a certain order among th...During convergence,after a link state change in traditional networks with a distributed control plane,packets may get caught in transient forwarding loops.Such loops can be avoided by imposing a certain order among the routers in updating their forwarding information bases(FIBs),but it requires some form of coordination among routers.As an alternative,a progressive link metric increment method has been proposed for loop-free forwarding without ordered FIB updates,but it takes longer to converge to the target state.In this paper,we show that the order of updates rarely matters for loop-free convergence when the failure inference-based fast reroute(FIFR)scheme with interface-specific forwarding is employed for dealing with link failures.The key insight is to have each router install the traditional interface-independent forwarding entries as soon as they are recomputed during convergence and install the recomputed interface-specific backwarding entries post-convergence.Our evaluation of 280 real and random topologies confirms that the order of updates does not matter with the proposed approach for 17336 out of 17339 links in those topologies.To handle such rare cases where the order matters,it can be coupled with progressive link metric increments to ensure loop-freedom with unordered FIB updates.Thus,the proposed approach,referred to as FIFR++,makes it possible to achieve disruption-free fast convergence and fast reroute without requiring any modification to the IP datagram and without needing any coordination between routers.展开更多
文摘在移动社交网络中,人们通过携带无线设备在近距离范围内彼此传递信息,从而达到信息的传播。由于移动社交网络中一般不存在端到端的连接,使得数据转发算法成为一个重要问题。文章从社区和节点的社会属性角度,利用社区和节点的影响力,提出了一种基于影响力的数据转发算法(data forwarding algorithm based on impact,DFAI)。在该算法中,携带数据包的节点只有在遇到影响力达到一定要求的节点时,才拷贝数据包给相遇节点。仿真试验结果显示,与经典的Epidemic和Label算法相比,DFAI可以明显降低网络开销,同时接近Epidemic算法达到的最大传递率。
文摘命名数据网(named data networking,NDN)作为一种新型的互联网架构,旨在应对日益增长的数据流量。基于其消费者驱动的内容检索模型,NDN自然地支持消费者移动性。然而生产者移动性仍然是一个具有挑战性的问题,需要额外的机制来提高生产者移动期间的数据可用性。针对该问题,提出一种可扩展的移动管理机制来支持生产者移动性。该机制利用网络终端在基于名称的NDN转发平面上建立了临时转发路径,并设计了缓存与重传机制支持时延容忍和时延敏感的应用数据流。最后在ndnSIM中建立了一个全面的仿真环境,对所提方案与现有解决方案进行了评估和比较。仿真结果表明,该机制能够充分支持生产者移动性。当速度为30 m/s时,丢包率仅为3.0%,平均传输延时为352.1 ms。此外,支持生产者移动性所需的额外消耗对于方案相比降低了49.18%。
文摘During convergence,after a link state change in traditional networks with a distributed control plane,packets may get caught in transient forwarding loops.Such loops can be avoided by imposing a certain order among the routers in updating their forwarding information bases(FIBs),but it requires some form of coordination among routers.As an alternative,a progressive link metric increment method has been proposed for loop-free forwarding without ordered FIB updates,but it takes longer to converge to the target state.In this paper,we show that the order of updates rarely matters for loop-free convergence when the failure inference-based fast reroute(FIFR)scheme with interface-specific forwarding is employed for dealing with link failures.The key insight is to have each router install the traditional interface-independent forwarding entries as soon as they are recomputed during convergence and install the recomputed interface-specific backwarding entries post-convergence.Our evaluation of 280 real and random topologies confirms that the order of updates does not matter with the proposed approach for 17336 out of 17339 links in those topologies.To handle such rare cases where the order matters,it can be coupled with progressive link metric increments to ensure loop-freedom with unordered FIB updates.Thus,the proposed approach,referred to as FIFR++,makes it possible to achieve disruption-free fast convergence and fast reroute without requiring any modification to the IP datagram and without needing any coordination between routers.
文摘在软件定义网络(software-defined networking,SDN)中,OpenFlow交换机通常采用三态内容可寻址存储器(ternary content addressable memory,TCAM)存储流表,以支持快速通配查找.然而,TCAM采用并行查找方式,查找能耗高,因此有必要为OpenFlow交换机选择合适的TCAM容量,以平衡分组转发时延和能耗.针对软件定义数据中心网络(software-defined data center network,SD-DCN)这一典型应用场景,利用多优先级M/G/1排队模型刻画OpenFlow交换机的分组处理过程,进而建立OpenFlow分组转发时延模型.同时,基于网络流分布特性,建立TCAM流表命中率模型,以求解OpenFlow分组转发时延与TCAM容量的关系式.在此基础上,结合TCAM查找能耗,建立OpenFlow分组转发能效联合优化模型,并设计优化算法求解TCAM最优容量.实验结果表明:所提时延模型比现有模型更能准确刻画OpenFlow分组转发时延.同时,利用优化算法求解不同参数配置下的TCAM最优容量,为SD-DCN实际部署提供参考依据.
