This article tells you about the description of HLR VLR and AUC and also about the role of HLR VLR and AUC.
Role of HLR VLR and AUC:
HLR (home location register): it is the component of a GSM. It gives the information of the subscriber to the msc. When a user want to connect call then BSC transfer the call to the msc, MSC wants information whether the subscriber is from the same msc or from other for this MSC call to the HLR and VLR. HLR gave the info to the MSC and call will be connected.
the HLR is a central database that contains details of each mobile subscriber that is
authorized to use the GSM network.
one HLR can work with one imsi.
VLR ( visitor location register):
it is the component of gsm architecture. VLR is connected with MSC and contain information about the mobile subscriber which came from the other MSC.
when the subscribe from other MSC came into the MSC the MSC want the information of that user and it calls to the vVLR and BSC for this.vlr provide TMSI (temporary mobile subscriber identity) to user and after that MSC allowed the user to use the network.and call termination problem will not be occurred with subscriber or user of the network.
AUC (authentication center):
the AUC is a device that is used to locate sim card that want to connect with gsm network. If authentication is not completed user cant use the services of the network. After authentication HLR allowed to use services. When authentication is completed a key is generated that is used to connect mobile user and gsm network.