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pls am new in the forum.I salute you guys effort.
I want to understand the difference and the funtion of vlr and hlr in a mobile network.
thankshi delegun
Functions of HLR.
Generally as a database for a subscribers and other network elements. Specifically, HLR is a references for subscriber and other network elements such a VLR,SMS,USSD etc. like HLRENQuries,
Functions of VLR.
Generally place for subsribers. Specifically, location update, handovers,paging, charging, call set up etc.
To be more specific…
HLR (Home location Register)is the Home location for a subscriber in and has the subscriber prifile information. Upon registration the profile gets downloaded into the VLR. The HLR can be standalone and can serve multiple Switching centers (MSCs) whereas VLR is generally integrated with every MSC. In any network (Home or visited) calls would be handled by respective VLR, once the subscriber is registered and the profile has been dowloaded from the HLR.
HLR-Holds Permanent Subscriber Details of a particular PLMN + MSC Address wher it is presently Registered.A static DB.Fixed DB Point from where other Network Elements gets information if they need for any activitys inside the newtork.Can work as Integrated/Standalone.
VLR-Holds the subscribers service related informations.Knows exact location of the MS.Dynamic Database keeps track of Visitors who are regsitered in the MSC Service Area.Gets the copy of Subscriber data from HLR.Always integrated in MSC ( I never seen one Stand Alone-In DX200 Nokia Internally it is kept Seperately but the SW Treats as the Integrated Part )
Rgds
Scot
Hi, I want to know, when a subscriber is raoming, will his details be in the HLR of the roaming network. And how does the home PLMN come to know where he is roaming?
Hi Naveen,
When MS is roaming, its details will be transfered from old VLR (or its home HLR) to the visited VLR only.
When MS roaming from one location area (LA) to another, it will perform location updating procedure. Hence, the HLR always knows the lastest LA of the MS.
Location Update procedure always involves HLR…..So HLR will get the Request for a Subscrbtion check from the MSC which serves at that moment.
So HLR stores the MSC Address during the completion of LUP Procedure.
Rgds
Compared to a Fixed (Wireline) customer, a Mobile End User (GSM/3G/4G/etc..) is moving from one location to another. The HLR – Home Location Register – which is a database stores the End User’s Location (current MSC/VLR). The VLR – Visitor Location Register – stores the downloaded HLR profile (Service flags, CAMEL Profile, etc..).
As 3GPP is evolving you will also need to understand HSS and UDC.
VBR/ Wallis Dudhnath
