`The functional entities included in the CDN network include content caching devices, content switches, content routers, CDN content management systems, etc.` Content caching is a CDN network node located at the user access point. It is a content providing device for end users. It can cache static Web content and streaming media content to achieve content edge propagation and storage, so that users can access it nearby. The content switch is at the user access concentration point, which can b...