Specifications

Interface Protocols
Operating Characteristics
August 08, 2000 68P81095E55-E 3-21
Mobile Switching Center
Interconnect Call Processing uses data in the MSC to define and control access to the
iDEN system and the system services.
MSC - Home
Location Register
The MSC-Home Location Register (HLR) is where the MSs permanent subscriber
Interconnect records are stored. The database may be internal to the MSC (iNode) or
it may be a large, remote, shared, system or service. Remote HLR systems are more
common because the database processing demands on the MSC may have an adverse
affect on call processing.
All MS identities and the various supplementary services are provisioned in the
HLR. The HLR performs Subscriber Access Control. It is queried each time an
interconnect call is initiated or interconncet call features are requested.
The MSC manages access to the system by verifying requests for service against a
database of subscriber privileges. The HLR database also contains Mobile Station
Identification data and Fixed Network Data.
The HLR Mobile Station Data includes:
•IMSI
• Temporary Mobile Station Identity (TMSI)
• MS Authentication (Random Number and Signature Number table)
• Telephone Unit ID
The HLR Fixed Network data includes:
• Services: Allow/Deny
• Telephone, Short Message Service, Data
• Telephone Access Privileges
• Local Calls only, Inbound Calls only
- Supplemental Services: Telephone
- Call Waiting, Call forwarding, etc.
MSC - Visited
Location Register
The MSC - Visited Location Register (VLR) contains the most recent location
information on each MS. The MSC VLR is part of the MSC. As an MS travels it
reports its location to the MSC which updates the VLR with the latest data. The VLR
contains the same MS ID and subscriber specific data that is contained in the HLR.
Additionally, the VLR contains the current location and status of the MS.
The VLR is a fast access database storing data about the MS units that are now or
have been recently active. It is a fast look up for Interconnect calls permissions and
services. The VLR speeds call setup because the entire HLR subscriber database on
disk is not searched.