Excuse me, the network structure of my 4-star hotel is 20M optical fiber of telecom, and then a telecom device (like a model) is connected to a switch.

1: The modem-like thing connected to the telecom optical fiber is called optical cat, which plays the role of signal conversion. Generally, one end is connected to the optical fiber and the other end is connected to the network cable.

2. What you are talking about should not be a switch, but a device similar to a security gateway, which can record and restrict some illegal network behaviors. If the public network IP is set, you can directly log in remotely for management.

3. Routers are mainly used for NAT translation, which is often called dragging N, so it is necessary.