
6 ◾ IP Communications and Services for NGN
e A interface is a standardized open interface with a 64 kbps user chan-
nel. is interface connects the BSC with the network and switching subsystem
(NSS). is subsystem performs switching, mobility management, interconnection
to other networks, and system control functions. It has a GSM mobile switching
center (GMSC), home location register (HLR), virtual location register (VLR),
authentication center (AUC), equipment identity register (EIR), and operating net-
work management center (OMC). e MSC controls all connections via a sepa-
rated network to/from a mobile terminal within the domain of ...