Based Plug-in Framework Of The Cdn Simulation System Design And Realization

The performance of key technologies of Content Delivery Network (CDN), including content scheduling, content aging, metadata locating and so on, has great influence on quality of service and user experience of CDN. The primary approach to improving the performance of CDN is to carry out overall comparison and evaluation for the key technologies, and work out optimized algorithms. However, it is relatively difficult to test the algorithm in running CDN system. Accordingly, CDN simulating system should be employed for the algorithm researches. However, some of the existing CDN simulating systems have the following two problems:Firstly, lack of extensibility. There are lots of algorithms of every key technology of CDN. This requires simulating various algorithms rapidly and analyzing the experimental results. However, most existing CDN simulating systems do not support for the replacing of key components because of its high coupling of modules.Secondly, lack of support for third-part development. Most existing CDN simulating systems are lack of universality because they are designed to verify their own algorithms and therefore cannot simulate others.Challenged by these two problems, this thesis designs and implements a CDN simulating system based on plug-in framework.The plug-in framework features extensibility, low coupling of modules and support for the third-part add-ons. It is unnecessary for us to understand the details of original system if we develop new algorithms based on the framework. The only thing we need do to simulate the key technology is to implement the algorithm and plug it in the system. Therefore, the researchers can focus on the research of the algorithm itself.The CDN simulating system constructed on this framework implements a variety of key algorithms, achieves the interchangeability, and exemplifies the characteristics of plug-in framework from the other side. The CDN simulating system based on plug-in framework consists of communication plug-in, main plug-in, node group plug-in and distributed file system plug-in. Distributed file system plug-in is the key plug-in of the system, which includes the nodes behavior simulation and various key technologies of CDN system. This thesis designs the distributed file system based on CDN, and implements the distributed file system plug-in.This thesis introduces the design of plug-in framework firstly and designs and implements the CDN simulating system based on the framework. Secondly, this thesis investigates and tests a variety of algorithms within the simulating system, and has an analysis and comparison of algorithms according to the test results.