Introduction to MDN The role of MDN in the video-on-demand system In VoD on-demand, MDN provides VoD data caching and intelligent scheduling functions, which effectively reduces MS VoD data requests and alleviates the huge data read by the media content provider (MCP) The access and transmission capabilities greatly increase the number of MSs served by the MCP, and have good scalability for the number of end users that the MCP can serve. MDN storage strategy According to the on-demand behavior of users in 3TNet video on-demand, only 1% of users have completely watched a movie, 99% of users have only watched part of the movie, and 75% of users have not watched The beginning of the film starts from a block in the middle or back. It can be seen that the existing storage strategy has many shortcomings for the actual system. The block-based storage strategy proposed in this paper will solve these problems. Dongguan Guancheng Precision Plastic Manufacturing Co., Ltd. , https://www.dpowergo.com
MDN is located between MCP and MS, and is composed of MDN management module MM, directory server DS (multi-directory server), virtual content server VCS and several PN nodes distributed in the network (denoted as P1, P2, P3 in the figure) The main function is to provide wide-area media content distribution services, and its storage strategy is shown in Figure 2. 
Figure 2 MDN storage strategy
The storage strategy of the MDN system is shown in Figure 2. All movies are divided into 4 levels. 0: The most popular movie (HOT); 1: The more popular movie (WARM); 2: The more popular movie (COOL); 3: The popular movie (COLD). In the figure, MS0, MS1, MS2, and MS3 represent the percentage of movies of each rating stored on the MS, and P1, P2, and P3 represent the percentage of movies of each rating stored on the PN. storage. Assuming that there are N videos in the system (all videos are the same size as T), among which HOT, WARM, COOL, and COLD have N0, N1, N2, and N3, respectively, the storage space MSstorage of MS and PN in the system can be obtained. PNstorage is as follows: 