What do you mean by short messages in the network and short messages between networks?

Hello, what's the difference between online short messages and intranet short messages?

In-network short message means that the mobile phone numbers used by the sender and the receiver belong to the same communication operator (for example, sending short messages from electrical signals to electrical signals).

Internet SMS means that the numbers used by the sender and the receiver belong to different communication operators (for example, the telecom number sends SMS to the number of China Mobile or China Unicom).