Why did China Telecom delay SMS?

Short message delay is a kind of network delay, which is a normal phenomenon.

When we communicate by SMS, unlike voice communication, the two users are not directly connected. When user A sends a short message to user B, user A edits the short message and sends it. At this time, the short message is temporarily stored in the telecom server and enters the queue. Then the server will confirm communication with user B (this process is imperceptible to the user), and the server will send a short message to user B only when it is confirmed that user B is in the power-on state. This is the reason for the delay of SMS.

Of course, this is also a special design of SMS communication, in order not to miss SMS when user B is not turned on, because SMS can be temporarily stored in the server of telecom service provider.