Section: 4.3.19 Core Network node resolution 4.3.19.1 General
Content: The indication of mapped or native GUTI shall be signalled by the UE to the MME as an explicit indication in Attach Request and TAU Request messages. The indication of mapped or native P-TMSI/RAI shall be signalled by the UE to the SGSN as an explicit indication in Attach Request and RAU Request messages. The MME/SGSN resolves the old MME/SGSN using old GUTI respective old P-TMSI/RAI sent in the Attach request and TAU/RAU request messages, and determines if the old GUTI or the old P-TMSI/RAI is mapped or native by one of the following two methods: - Indication using most significant bit (MSB) in LAC and MME Group ID. - Explicit indication sent from UE to MME and SGSN.