Thomas Kunz
Systems and Computer Engineering
29
Network and Switching Subsystem
nNSS is the main component of the public mobile network GSM
–switching,
mobility management, interconnection to other networks, system control
nComponents
–Mobile
Services Switching Center (MSC)
controls all connections via a separated network to/from a mobile terminal within the domain of the MSC - several BSC can belong to a MSC
controls all connections via a separated network to/from a mobile terminal within the domain of the MSC - several BSC can belong to a MSC
–Databases
(important: scalability, high capacity, low delay)
nHome Location Register (HLR)
central master database containing user data, permanent and semi-permanent data of all subscribers assigned to the HLR (one provider can have several HLRs)
central master database containing user data, permanent and semi-permanent data of all subscribers assigned to the HLR (one provider can have several HLRs)
nVisitor Location Register (VLR)
local database for a subset of user data, including data about all user currently in the domain of the VLR
local database for a subset of user data, including data about all user currently in the domain of the VLR