GSM: What kind of information is kept in HLR and VLR ?

Question

In Practical, how far a BTS cover ?

Answer 1

Whenever a UE connects to a GSM network, it is served by a MSC. Each MSC maintains a database for all active subscribers knows as VLR. HLR is a permanent database which contains many more information irrespective of which MSC is serving to UE.
This is the basic understanding I have in GSM network.

Answer 2

HLR stands for Home Location Register.The HLR is a database used for storage and management of subscriptions.It stores the permanent data of the subscribers.It stores the service profile,location information and activity status.When a user buy's a SIM card then all the information is registered in the HLR of that operator.

VLR stands for Visitor Location Register.The VLR is a database used for storage of temporary information of the subscriber's.It is integrated with MSC just like HLR. Whenever a user roams into the new MSC it request's the moblie station for the HLR information of the subscriber.If the user makes the call the VLR will set up the call without interrogating with the HLR each time.