03.713GPPFunctional descriptionLocation Services (LCS)Release 1999Stage 2TS
A PLMN can have one or more of the following roles in supporting the LCS service.
Gateway PLMN (GPLMN)
The PLMN in which a location request originates. For an MT-LR, the GPLMN contains the GMLC.
Home PLMN (HPLMN)
The home PLMN for the MS being located. The HPLMN contains the HLR for the located MS.
Visited PLMN (VPLMN)
The PLMN currently serving the MS being located. The VPLMN contains the MSC/VLR serving the located MS, the SMLC and any LMUs used to perform the location.