Mobile entities
The Visitor Location Register (VLR)
A mobile station roaming in an MSC area is controlled by the
Visitor Location Register in charge of this area.
When a mobile station enters a new location area it starts its
The MSC in charge of that area notices this registration and
transfers to the Visitor Location Register the identity of the
location area where the MS is situated.
If this MS is not yet registered, the VLR and the HLR exchange
information to allow the proper handling of calls involving the MS.