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VLR & HLR PowerPoint Presentation

VLR & HLR

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VLR & HLR

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  1. VLR & HLR

  2. VLR & HLR • Visitor Location Register (VLR): AVLR is acurrent subset of HLR for a particular cell. • Whenever a subscriber enters a new cell, its current location is stored in VLR representing that cell. • The entry is removed when the subscriber leaves that cell. • The information about a subscriber is replicated in HLR and VLR to achieve faster location search which begins from VLR and ends in HLR if the entry is not found in the VLR. • The VLR data are not used for any administrative purpose; it merely serves as a location identifier.

  3. VLR & HLR • HLR and VLR are huge databases maintained by high-power servers, often a Unix workstation. • Tandem, which is part of Compaq (a part of HP), made the server and called it HLR when used for cellular system. • A large number of mobile units use the same HLR, and there are usually more than one HLR for nationwide cellular system.

  4. VLR & HLR • For example, Motorola uses more than 60 HLRs nationwide. • The processing of HLR is not complex, so it does not need sophisticated database functionality. • The recent trends is to distribute HLRs and use distributed processing approaches for its • management