(S13 and S13’ Interfaces) – With reference to the SAE and the Evolved Packet Core (EPC), the interface S13 is defined between the Equipment Identity Register (EIR) and the MME and the interface S13′ is defined between EIR and SGSN. The S13 and S13′ interfaces are based on the Diameter protocol and are used to check the status of the UE (e.g. if it has been reported stolen or blacklisted). The MME or SGSN checks the ME Identity by sending the Equipment Identity to an EIR and analyzing the response.
