Classification of traditional telecommunications networks

The telecommunications network consists of three parts: the core network, the access network (AN) and the customer premises network (CPN). The core network and access network are public telecommunications networks, CPN is a user-owned communication network, and traditional CPN is a single user. One side of the access network is the core network, which is mainly composed of various service networks, and the other side is the user. The access network serves as a link between the previous and the next, providing services of the core network to users through the access network. The access network is a transparent transmission system that does not provide services by itself. User terminals cooperate with the core network to provide various services.