Research On Key Technologies Of Imerged Content Delivery Network

The availability, reliability have become the key issue of Internet technology because of the growth of Internet traffic and the demand of access speed. Content delivery networks focus on optimizing Internet quality of service. With the progress of cloud computing, mobile Internet and dynamic Web content technology, content delivery technology becomes specialization, customization. The content routing, management, and security of content delivery networks face new challenges. Based on above reasons, in this dissertation, we investigate performance and security of CDN to deal with the traffic cost, quality of service and data transmission network security. First, the content outside which may cause large number of traffic and decreasethe quality of service should be stored in order to decrease the inter-domain traffic. To solve this problem, we first propose hierachy deployment mechanism, which is divided into two layers. The purpose of the first level, which deploy content nodes at the inter-domain entrances, is reducing the inter-domain traffic. The inner deployment strategy based on greedy algorithm selects the content node from core routers. Then we design RCBF (Record Counter Bloom Filter) index structure and synchronization mechanisms to enhance the content routing performance by improving the environment under the CDN. Second, we investigate the content management problem when the location ofsurragate servers has been fixed. Content management includes local cache management and remote cache pushing. In order to extend the life cycle of popular cache object, we propose cache replacement policy based on access density and object size. Then considering the cache data are depended on user behaviors, we analyze the application layer data in order to evaluate the object popularity. Cache data pushing scheme based on the value of popular object is further proposed to deal with the access delay and network performance. Third, in order to improve the quality of service and decrease the network riskis a key task for ISP merged CDN. The previous network monitoring and detection mechanisms neglect the potential of social relations in these malicious network behaviors. This paper proposes a novel network group behavior clustering model based on trust through exploring the behavior similarity to construct trusted CDN. This model establishes the trust relationship between the nodes of the network using the network communication topology. Then we use relevant trust concept which is used to increase the trust value between two weak correlation nodes. Based on the clustering method, we reduce the network risk for CDN.Finally, we design and implement a content delivery system for ISP. The system is different from trandistional CDN system in two parts:1. Parsing the network data passively and hierachy deployment;2. Security monitoring for ISP. The system includes three parts: information collection, cache management and auditing offline. Under the practical evaluations, our deployment machanism, cache management and security monitoring method achieve our initial research objectives.