The short message has been serialized. What happened?

Refers to the unique serial number that needs to be generated when a mobile phone network sends a short message. This serial number can identify the receiver, sender and sending time of the short message. Under normal circumstances, the SMS serial number will be generated automatically, without user's processing, but if the receiver has problems in the process of receiving the SMS, it can query the detailed information about the SMS according to the SMS serial number.