The MPE determines if an IP-CAN Session requires an IMS emergency session based on the PDN-id. The MPE device stores a configurable list of Emergency APNs that are valid for the the MPE device. For emergency APNs, the IMSI cannot be present. The MPE device supports requests for PCC and QoS Rules that do not include an IMSI. See Viewing the Audit Log.
The MPE device verifies the Service-URN if the IMS service information is associated with a UE IP address belonging to an emergency APN. The MPE device stores a configurable list of Service-URNs designated for emergency services. If the IMS service information does not contain an emergency-related indication and the UE IP address is associated with an emergency APN, the MPE rejects the IMS service information provided by the AF.