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
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
The virtual network(VN) embedding/mapping problem is recognized as an essential question of network virtualization. The VN embedding problem is a major challenge in this field. Its target is to efficiently map the vir...The virtual network(VN) embedding/mapping problem is recognized as an essential question of network virtualization. The VN embedding problem is a major challenge in this field. Its target is to efficiently map the virtual nodes and virtual links onto the substrate network resources. Previous research focused on designing heuristic-based algorithms or attempting two-stage solutions by solving node mapping in the first stage and link mapping in the second stage. In this study, we propose a new VN embedding algorithm based on integer programming. We build a model of an augmented substrate graph, and formulate the VN embedding problem as an integer program with an objective function and some constraints. A factor of topology-awareness is added to the objective function. The VN embedding problem is solved in one stage. Simulation results show that our algorithm greatly enhances the acceptance ratio, and increases the revenue/cost(R/C) ratio and the revenue while decreasing the cost of the VN embedding problem.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.
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Project supported by the National Basic Research Program(973)of China(Nos.2011CB302901 and 2012CB315801)Fundamental Research Funds for the Central Universities,China(No.2011RC0118)
文摘The virtual network(VN) embedding/mapping problem is recognized as an essential question of network virtualization. The VN embedding problem is a major challenge in this field. Its target is to efficiently map the virtual nodes and virtual links onto the substrate network resources. Previous research focused on designing heuristic-based algorithms or attempting two-stage solutions by solving node mapping in the first stage and link mapping in the second stage. In this study, we propose a new VN embedding algorithm based on integer programming. We build a model of an augmented substrate graph, and formulate the VN embedding problem as an integer program with an objective function and some constraints. A factor of topology-awareness is added to the objective function. The VN embedding problem is solved in one stage. Simulation results show that our algorithm greatly enhances the acceptance ratio, and increases the revenue/cost(R/C) ratio and the revenue while decreasing the cost of the VN embedding problem.
