Section: 6.1 Identification by temporary identities 6.1.1 General
Content: This mechanism allows the identification of a user on the radio access link by means of a temporary mobile subscriber identity (TMSI/P-TMSI). A TMSI /P-TMSI has local significance only in the location area or routing area in which the user is registered. Outside that area it should be a accompanied by an appropriate Location Area Identification (LAI) or Routing Area Identification (RAI) in order to avoid ambiguities. The association between the permanent and temporary user identities is kept by the Visited Location Register (VLR/SGSN) in which the user is registered. The TMSI/P-TMSI, when available, is normally used to identify the user on the radio access path, for instance in paging requests, location update requests, attach requests, service requests, connection re-establishment requests and detach requests. The procedures and mechanisms are described in 3GPP TS 43.020[ Security related network functions ]  [8] and TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [9]. The following sections contain a summary of this feature.