System for retrieving external identifier of terminal

A system for retrieving an External Identifier (EID) of a terminal, comprising a Machine Type Communications (MTC) server, wherein a processor of the MTC server is configured to be capable of executing programmed instructions comprising:

• storing a corresponding relationship between an EID of a terminal and a Reference Number (RN) of the EID of the terminal;
• and
• when a terminal responds to a trigger request from a Machine Type Communications (MTC) server, retrieving an EID of the terminal which corresponds to an RN according to the RN of the EID of the terminal and the corresponding relationship;
• wherein the RN of the EID of the terminal is pre-configured at the network side, or dynamically allocated by a Core Network (CN) network element at the network side;
• wherein storing the corresponding relationship between an EID of a terminal and an RN of the EID of the terminal is:
• storing information of the terminal which is contained in a user information response message transmitted by an HSS, allocating the RN of the EID of the terminal for the terminal, and storing the corresponding relationship between the RN of EID of the terminal and the EID of the terminal;
• and
• using an IMSI contained in the user information response message and the RN of the EID of the terminal allocated, to create a trigger message and transmitting the trigger message to a serving MME of the terminal.