Load Balance Research In CDN Network

As a main type of broadband application, video service based on stream media technology needs to guarantee end-to-end quality, which requires high quality transportation system. Comparing to traditional network, Content Delivery Network technology can implement distributed service and provide better network support to stream media business. Server load balance system is the essential part for user-access dispatch. The whole network efficiency and content service quality directly is decided by the server load balance algorithm.The task of load balance system is to dispatch the user'requests to a suitable point, which will provide service to the user, in the whole network. According to geography structure, we divide server load balance into 2 layers: GSLB (Global Server Load Balancing) and SLB (Server Load Balancing). GSLB is load balance for server clusters in different locations with different network structures. SLB is load balance inside local server cluster.ContEx? is a software content distribution solution, which realizes content guide, serve, dispatch and management by pure software. I am mainly responsible for system structure for load balance in this project. I use CRD and CSG to realize two-layer (global and local) load status report system, which is an integral part of load balance system.As a global content router, CRD is responsible for global balance, which searches for best serving point in CDN network. In order to execute shortest dispatch, it adopts static routing as primary strategy and dynamic routing as complementary strategy.As a local content router, CSG is responsible for local balance, which searches for best serving equipment inside target point. It adopts local content image table as primary strategy and load balance algorithm as complementary strategy.There are two key factors to decide which local balance dispatching strategy is better and can be realize easier. The first is Load balance algorithm and second is network system status checking method and capability.We have performed performance test and functional test for CRD/CST. The performance test is to check whether it can support required applications and protocols. The functional test is to check parallel requirements process capability and dispatch delay.CDN is a key technology to provide cosmically high quality stream media service. It is becoming mature and applied widely. According to running CDN network experience, it can improve service quality for stream media and reduce bandwidth requirement for backbone network remarkably. At the same time, its widely deployment can make our communication service provided ready for IPTV development. How to make it more suitable for IPTV business requirements is the next topic to research.