Section: 4.3.19.2 MSB in LAC and MME Group ID
Content: For PLMNs deployed with such mechanism the MME differentiates between a GUMMEI mapped from P-TMSI/RAI and a native GUMMEI based on the value of most significant bit of the MME Group ID; i.e. the MSB is set to "0" then the GUMMEI is mapped from P-TMSI/RAI and if MSB is set to "1", the GUMMEI is a native one, as specified in TS 23.003[ Numbering, addressing and identification ]  [9]. For PLMNs deployed with such mechanism the S4-SGSN differentiates between a P-TMSI/RAI mapped from GUTI and a native P-TMSI/RAI based on the value of most significant bit of the LAC; i.e. the MSB is set to "1" then the P-TMSI/RAI is mapped from GUTI and if MSB is set to "0", the P-TMSI/RAI is a native one, as specified in TS 23.003[ Numbering, addressing and identification ]  [9].