Research On Evolution Mechanism And Invulnerability Of Network Topology

As the high development of network, enormous interest has been devoted to the study of network topology due to its universality and essentiality. Since the network topology is a main factor that affects the performance of routing protocols, it is vital to design a network which is scientific and reasonable. The current network topology models are not only reflect the characteristics of real networks, but also are vulnerable against both failure and attack. Relied on the research and development of the project of fast self-healing routing protocol and experiment system , this dissertation makes a detailed research on the network s evolution mechanism, the optimization and evaluation about network invulnerability, and finally provides cogent technique support for the simulation environment of fast self-healing routing protocol. The main work and contributions are outlined as follows:■Based on the three characteristics of real networks and the concept of local world , a Local-World based evolving network model with Tunable Clustering coefficient (LWTC) is designed, which fully considers all kinds of evolving forms of nodes and links, realizes the tunable clustering coefficient according to parameters, and adapts mean-field theory to get the analytical expression of power-law degree distribution. The simulation results not only proves the correctness of analytical results, but also indicates that the clustering coefficient is far better than local world model, and exactly describes many characteristics of real networks.■By analyzing the cause of network vulnerability, two methods to optimize the invulnerability are put forward. From the perspective of whole network, the optimal network model based on network structure entropy is proposed, and improves the generation algorithm according to the optimization results; from the perspective of local network, this dissertation analyzes the relationship between network resilience and key nodes, then uses split method towards key nodes. Both theory prove and simulation results show that the two methods simply and effectively enhances the network invulnerability, and provides techniques for design of invulnerable network Invulnerable LWTC (ILWTC).■Presenting a novel evaluation scheme for network invulnerability. Due to the characteristic changes of network topology against failure and attack, first a new measurement about network performance is given which named network efficiency parameter EFF(G), then two new measurements of network invulnerability based on EFF(G) are put forwarded for the two different damages, finally the comparative analysis among ILWTC model, LWTC model and local world model show that the invulnerability of ILWTC model is the strongest. ■From the simulation requirement of fast self-healing routing protocol, the ILWTC topology module is added in BRITE to get the ILWTC topology generator, which provides simulation environment for SSFNet to realize the fast self-healing routing protocol. The ILWTC generator has been successfully applied to research and development of fast self-healing routing protocol and experiment system .