Visitor location register (VLR) 

•  The role of a VLR in a GSM network is to act as a temporary storage location for 

subscription information for MSs, which are within a particular MSC service 

area.  

•  Thus, there is one VLR for each MSC service area.  This means that the MSC 

does not have to contact the HLR (which may be located in another country) 

every time the subscriber uses a service or changes its status.  

•   The VLR is always integrated with the MSC

•  For the duration when the MS is within one MSC service area, then the VLR 

   contains a complete copy of the necessary subscription details, including the 

   following information:  

  Identity numbers for the subscriber  

  Supplementary service information (e.g. Does the subscriber has call 

     waiting activated or not) 

  Activity of MS (e.g. idle or busy) 

  Current Location Area of MS