The Analysis Of The Large-scale Network's Characteristics And The Study Of Risk Assessment

In recent years, with the rapid growing of the network scale, the internet topology structures always keep evolving state. The internet attacks make many networks paralysis, bringing about very bad influence. Because of the large-scale network's huge nodes and complex structures, the characteristics exited are differ from the traditional small-scale network. Moreover, the researches on the large complex network are still in exploration and development. The available topology models and security assessment methods in the small network are not suitable for the large-scale network. Therefore, to study the security of the large-scale network need thoroughly analyze and summarize the characteristics and attributes.This paper firstly analyzed the large-scale network's characteristics, summed up their particular properties from the view of network topology, discussed the typical network models combining with the network properties. Modeling the large-scale network can be a complicated process. Then, it analyzed the differences between the large-scale network and small-scale works from the aspects such as the characteristics, topology models, evolving mechanism, security influence and so no.Secondly, this paper generally analyzed the security factors which the large-scale network faced. We introduced the classification of the network vulnerability, assets and threats, also drew up some principles of choosing levels about evaluating values, analyzed the topology's influence on the security. Based on all of these, we proposed a risk assessment model characterized by layered assessing and allocating weighing levels.Finally, we simulated the DDOS--a typical threat in the large-scale network, in the ns-2 platform. By changing the network topology and parameters of the attack, we compared the experiment results and calculate the network's risk value based on the layered large-scale network risk assessment model. This is effective in evaluating the network's security situations under the special threaten—DDOS attacks.