Due to minimum consideration of an actual network topology, the existing peer-to-peer (P2P) overlay networks, such as CAN, Chord, Pastry and Tapestry, will lead to high latency and low efficiency. In TaChord, a topolo...Due to minimum consideration of an actual network topology, the existing peer-to-peer (P2P) overlay networks, such as CAN, Chord, Pastry and Tapestry, will lead to high latency and low efficiency. In TaChord, a topology-aware routing approach in P2P overlays and an improved design in Chord are presented. TaChord and other algorithms are evaluated by physical hops, interdomain-adjusted latency, and aggregate bandwidth used per message. Experimental results demonstrate that TaChord has the drastic improvement in routing performance where average physical hop is half that of chord, and the impact of cache management strategies in the TaChord overlay cannot be neglected.展开更多
数据中心网络的节能路由算法大体可分为流量感知和拓扑感知两大类.前者性能的好坏很大程度取决于流量矩阵预判的准确性.由于实际网络流量动态、随机产生,具有突发性,预判流量矩阵不一定与网络实时流量状态相符,因此,这类算法往往难以保...数据中心网络的节能路由算法大体可分为流量感知和拓扑感知两大类.前者性能的好坏很大程度取决于流量矩阵预判的准确性.由于实际网络流量动态、随机产生,具有突发性,预判流量矩阵不一定与网络实时流量状态相符,因此,这类算法往往难以保证突发流的可靠传输.而后者在休眠冗余设备时,仅从保证网络拓扑具有某种程度的连通性出发,并未考虑网络负载情况,可能导致低负载时设备空闲率较高,节能效果有限.为此,针对fat-tree拓扑的软件定义数据中心网络(software-defined data center network,SDCN),将网络流量因素引入拓扑感知节能路由机制,提出等效节点、最小网络连通子集、孤岛交换机、无效链路等概念以及辅助图模型和SDCN连通条件,给出多约束节能路由优化模型,同时还提出一种多约束节能路由算法(multi-constrained energy-saving routing,MER).MER算法在保证数据流的时延和可靠性要求前提下,尽可能多地休眠冗余交换机和链路,以降低网络能耗.最后,通过Mininet和Floodlight进行仿真测试.仿真结果表明:与文献中已有算法相比,MER具有更低的平均分组时延和丢包率,并且可以达到理想的节能效果.展开更多
The mismatch between the structured peer-to-peer （P2P） overlay network, which is based on Hashing, and the actual physical network, leads to query repeatedly passing through some nodes in the actual route when it is...The mismatch between the structured peer-to-peer （P2P） overlay network, which is based on Hashing, and the actual physical network, leads to query repeatedly passing through some nodes in the actual route when it is applied in Ad-hoc networks. An approach of getting an appropriate node identifier （ID） bearing its local physical information is proposed, in which the traditional theory of getting node ID through Hashing the node＇s Internet protocol （IP） address is abandoned, and a topology-aware overlay network suiting Ad-hoc networks is constructed. The simulation results show that the overlay network constructed in the proposed method can avoid the route being iteratively accessed. Meanwhile, it can effectively minimize the latency and improve the load balance.展开更多
Current peer-to-peer （P2P） applications suffer performance degradation from the problems such as load imbalance, topology mismatch between overlay and underlay, and instability caused by node joining and leaving. In...Current peer-to-peer （P2P） applications suffer performance degradation from the problems such as load imbalance, topology mismatch between overlay and underlay, and instability caused by node joining and leaving. In this paper, we propose the idea of implementing 2 functions of routing message and main- taining service index on different layers of overlay to deal with the aforementioned problems. Taking Chord as example, we design algorithms for building cluster and overlay and implement function-separated （FUSE） overlay with 2-dimensional address ID space We further propose an analytic model for describing node＇s load for evaluation. Simulation results indicate that, compared with 2-layer Chord-centered overlay in previous researches, this overlay excels in the metrics such as query path length, load, and query delivery ratio.展开更多
文摘Due to minimum consideration of an actual network topology, the existing peer-to-peer (P2P) overlay networks, such as CAN, Chord, Pastry and Tapestry, will lead to high latency and low efficiency. In TaChord, a topology-aware routing approach in P2P overlays and an improved design in Chord are presented. TaChord and other algorithms are evaluated by physical hops, interdomain-adjusted latency, and aggregate bandwidth used per message. Experimental results demonstrate that TaChord has the drastic improvement in routing performance where average physical hop is half that of chord, and the impact of cache management strategies in the TaChord overlay cannot be neglected.
文摘数据中心网络的节能路由算法大体可分为流量感知和拓扑感知两大类.前者性能的好坏很大程度取决于流量矩阵预判的准确性.由于实际网络流量动态、随机产生,具有突发性,预判流量矩阵不一定与网络实时流量状态相符,因此,这类算法往往难以保证突发流的可靠传输.而后者在休眠冗余设备时,仅从保证网络拓扑具有某种程度的连通性出发,并未考虑网络负载情况,可能导致低负载时设备空闲率较高,节能效果有限.为此,针对fat-tree拓扑的软件定义数据中心网络(software-defined data center network,SDCN),将网络流量因素引入拓扑感知节能路由机制,提出等效节点、最小网络连通子集、孤岛交换机、无效链路等概念以及辅助图模型和SDCN连通条件,给出多约束节能路由优化模型,同时还提出一种多约束节能路由算法(multi-constrained energy-saving routing,MER).MER算法在保证数据流的时延和可靠性要求前提下,尽可能多地休眠冗余交换机和链路,以降低网络能耗.最后,通过Mininet和Floodlight进行仿真测试.仿真结果表明:与文献中已有算法相比,MER具有更低的平均分组时延和丢包率,并且可以达到理想的节能效果.
基金supported by the National Natural Science Foundation of China (0672124)the Hi-Tech Research and Development Program of China (2007AA01Z221).
文摘The mismatch between the structured peer-to-peer （P2P） overlay network, which is based on Hashing, and the actual physical network, leads to query repeatedly passing through some nodes in the actual route when it is applied in Ad-hoc networks. An approach of getting an appropriate node identifier （ID） bearing its local physical information is proposed, in which the traditional theory of getting node ID through Hashing the node＇s Internet protocol （IP） address is abandoned, and a topology-aware overlay network suiting Ad-hoc networks is constructed. The simulation results show that the overlay network constructed in the proposed method can avoid the route being iteratively accessed. Meanwhile, it can effectively minimize the latency and improve the load balance.
基金Supported by the Natural Science Foundation of Hubei Province (2006ABA217)the Key Technological Problems Tackling Project of Wuhan (200750499172)
文摘Current peer-to-peer （P2P） applications suffer performance degradation from the problems such as load imbalance, topology mismatch between overlay and underlay, and instability caused by node joining and leaving. In this paper, we propose the idea of implementing 2 functions of routing message and main- taining service index on different layers of overlay to deal with the aforementioned problems. Taking Chord as example, we design algorithms for building cluster and overlay and implement function-separated （FUSE） overlay with 2-dimensional address ID space We further propose an analytic model for describing node＇s load for evaluation. Simulation results indicate that, compared with 2-layer Chord-centered overlay in previous researches, this overlay excels in the metrics such as query path length, load, and query delivery ratio.
