Home Location Register (HLR):
- It is a database for managing the mobile subscriber.
- HLR stores permanent data of subscriber which include subscribers service profile, location information and its activity.
- A home subscriber charges are less then the roaming subscriber.
Visitor Location Register (VLR):
- It is a database which consists of temporary information about subscribers which is used by MSC in order to provide services to visiting subscriber.
- MSC updates the VLRby determining which users are in roaming.
- Once, the roaming mobile information is updated, then MSC sends necessary information to roaming mobile subscribers so that roaming mobile call can be properly routed.