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
An improved on-demand multicast routing protocol(ODMRP), node classification on-demand multicast routing protocol(NC-ODMRP), which is based on node classification in mobile ad hoc networks was proposed. NC-ODMRP class...An improved on-demand multicast routing protocol(ODMRP), node classification on-demand multicast routing protocol(NC-ODMRP), which is based on node classification in mobile ad hoc networks was proposed. NC-ODMRP classifies nodes into such three categories as ordinary node, forwarding group(FG) node, neighbor node of FG node according to their history forwarding information. The categories are distinguished with different weights by a weight table in the nodes. NC-ODMRP chooses the node with the highest weight as an FG node during the setup of forwarding group, which reduces a lot of redundant FG nodes by sharing more FG nodes between different sender and receiver pairs. The simulation results show that NC-ODMRP can reduce more than 20% FG number of ODMRP, thus enhances nearly 14% data forwarding efficiency and 12% energy consumption efficiency when the number of multicast senders is more than 5.展开更多
In most network analysis tools the computation of the shortest paths between all pairs of nodes is a fundamental step to the discovery of other properties. Among other properties is the computation of closeness centra...In most network analysis tools the computation of the shortest paths between all pairs of nodes is a fundamental step to the discovery of other properties. Among other properties is the computation of closeness centrality, a measure of the nodes that shows how central a vertex is on a given network. In this paper, the authors present a method to compute the All Pairs Shortest Paths on graphs that present two characteristics： abundance of nodes with degree value one, and existence of articulation points along the graph. These characteristics are present in many real life networks especially in networks that show a power law degree distribution as is the case of biological networks. The authors＇ method compacts the single nodes to their source, and then by using the network articulation points it disconnects the network and computes the shortest paths in the biconnected components. At the final step the authors proposed methods merges the results to provide the whole network shortest paths. The authors＇ method achieves remarkable speedup compared to state of the art methods to compute the shortest paths, as much as 7 fold speed up in artificial graphs and 3.25 fold speed up in real application graphs. The authors＇ performance improvement is unlike previous research as it does not involve elaborated setups since the authors algorithm can process significant instances on a popular workstation.展开更多
A Minimizing Intermediate Multicast Routing protocol (MIMR) is proposed for dynamic multi-hop ad hoc networks. In MIMR,multicast sessions are created and released only by source nodes. In each multicast session proces...A Minimizing Intermediate Multicast Routing protocol (MIMR) is proposed for dynamic multi-hop ad hoc networks. In MIMR,multicast sessions are created and released only by source nodes. In each multicast session process,the source node keeps a list of intermediate nodes and destinations,which is encapsulated into the packet header when the source node sends a multicast packet. Nodes receiving multicast packets decide to accept or forward the packet according to the list. Depending on topology matrix maintained by unicast routing,the shortest virtual hierarchy routing tree is con-structed by improved Dijkstra algorithm. MIMR can achieve the minimum number of intermediate nodes,which are computed through the tree. No control packet is transmitted in the process of mul-ticast session. Load of the network is largely decreased. Experimental result shows that MIMR is flexible and robust for dynamic ad hoc networks.展开更多
The trustworthiness and security of routing in the existing Peer-to-Peer (P2P) networks can not be ensured because of the diversity of the strategies of P2P nodes. This paper firstly uses game theory to establish game...The trustworthiness and security of routing in the existing Peer-to-Peer (P2P) networks can not be ensured because of the diversity of the strategies of P2P nodes. This paper firstly uses game theory to establish game model of the strategies and profits of various types of routing nodes. Then,two incentive mechanisms for the corresponding stages of P2P trustworthy routing are proposed,namely trust associated mechanism and trust compensated mechanism. Simulation results show that the incentive mechanisms proposed in this paper will encourage cooperation actions of good nodes and restrain malicious actions of bad nodes,which ensure the trustworthiness of routing consequently.展开更多
In a Wireless Mesh Network(WMN),the convenience of a routing strategy strongly depends on the mobility of the intermediate nodes that compose the paths.Taking this behaviour into account,this paper presents a routing ...In a Wireless Mesh Network(WMN),the convenience of a routing strategy strongly depends on the mobility of the intermediate nodes that compose the paths.Taking this behaviour into account,this paper presents a routing scheme that works differently accordingly to the node mobility.In this sense,a proactive routing scheme is restricted to the backbone to promote the use of stable routes.Conversely,the reactive protocol is used for searching routes to or from a mobile destination.Both approaches are simultaneously implemented in the mesh nodes so that the routing protocols share routing information that optimises the network performance.Aimed at guaranteeing the IP compatibility,the combination of the two protocols in the core routers is carried out in the Medium Access Control(MAC)layer.In contrast to the operation in the IP layer where two routing protocols cannot work concurrently,the transfer of the routing tasks to the MAC layer enables the use of multiple independent forwarding tables.Simulation results show the advantage of the proposal in terms of packet losses and data delay.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Project(90304010) supported by the National Natural Science Foundation of China project supported by the NewCentury Excellent Talents in University
文摘An improved on-demand multicast routing protocol(ODMRP), node classification on-demand multicast routing protocol(NC-ODMRP), which is based on node classification in mobile ad hoc networks was proposed. NC-ODMRP classifies nodes into such three categories as ordinary node, forwarding group(FG) node, neighbor node of FG node according to their history forwarding information. The categories are distinguished with different weights by a weight table in the nodes. NC-ODMRP chooses the node with the highest weight as an FG node during the setup of forwarding group, which reduces a lot of redundant FG nodes by sharing more FG nodes between different sender and receiver pairs. The simulation results show that NC-ODMRP can reduce more than 20% FG number of ODMRP, thus enhances nearly 14% data forwarding efficiency and 12% energy consumption efficiency when the number of multicast senders is more than 5.
文摘In most network analysis tools the computation of the shortest paths between all pairs of nodes is a fundamental step to the discovery of other properties. Among other properties is the computation of closeness centrality, a measure of the nodes that shows how central a vertex is on a given network. In this paper, the authors present a method to compute the All Pairs Shortest Paths on graphs that present two characteristics： abundance of nodes with degree value one, and existence of articulation points along the graph. These characteristics are present in many real life networks especially in networks that show a power law degree distribution as is the case of biological networks. The authors＇ method compacts the single nodes to their source, and then by using the network articulation points it disconnects the network and computes the shortest paths in the biconnected components. At the final step the authors proposed methods merges the results to provide the whole network shortest paths. The authors＇ method achieves remarkable speedup compared to state of the art methods to compute the shortest paths, as much as 7 fold speed up in artificial graphs and 3.25 fold speed up in real application graphs. The authors＇ performance improvement is unlike previous research as it does not involve elaborated setups since the authors algorithm can process significant instances on a popular workstation.
文摘A Minimizing Intermediate Multicast Routing protocol (MIMR) is proposed for dynamic multi-hop ad hoc networks. In MIMR,multicast sessions are created and released only by source nodes. In each multicast session process,the source node keeps a list of intermediate nodes and destinations,which is encapsulated into the packet header when the source node sends a multicast packet. Nodes receiving multicast packets decide to accept or forward the packet according to the list. Depending on topology matrix maintained by unicast routing,the shortest virtual hierarchy routing tree is con-structed by improved Dijkstra algorithm. MIMR can achieve the minimum number of intermediate nodes,which are computed through the tree. No control packet is transmitted in the process of mul-ticast session. Load of the network is largely decreased. Experimental result shows that MIMR is flexible and robust for dynamic ad hoc networks.
基金Supported by the Hi-Tech R&D Program (863) of China (2006AA01Z232)the Research Innovation Program for Graduate Student in Jiangsu Province (CX07B-11OZ)
文摘The trustworthiness and security of routing in the existing Peer-to-Peer (P2P) networks can not be ensured because of the diversity of the strategies of P2P nodes. This paper firstly uses game theory to establish game model of the strategies and profits of various types of routing nodes. Then,two incentive mechanisms for the corresponding stages of P2P trustworthy routing are proposed,namely trust associated mechanism and trust compensated mechanism. Simulation results show that the incentive mechanisms proposed in this paper will encourage cooperation actions of good nodes and restrain malicious actions of bad nodes,which ensure the trustworthiness of routing consequently.
文摘In a Wireless Mesh Network(WMN),the convenience of a routing strategy strongly depends on the mobility of the intermediate nodes that compose the paths.Taking this behaviour into account,this paper presents a routing scheme that works differently accordingly to the node mobility.In this sense,a proactive routing scheme is restricted to the backbone to promote the use of stable routes.Conversely,the reactive protocol is used for searching routes to or from a mobile destination.Both approaches are simultaneously implemented in the mesh nodes so that the routing protocols share routing information that optimises the network performance.Aimed at guaranteeing the IP compatibility,the combination of the two protocols in the core routers is carried out in the Medium Access Control(MAC)layer.In contrast to the operation in the IP layer where two routing protocols cannot work concurrently,the transfer of the routing tasks to the MAC layer enables the use of multiple independent forwarding tables.Simulation results show the advantage of the proposal in terms of packet losses and data delay.
