08.023GPPBase Station System - Mobile Services Switching Centre (BSS-MSC) Interface - Interface PrinciplesRelease 1999TS
The signals between BSS and MSC are classified under three headings:
Where DTAP BSSMAP and BSSAP are as defined in 3GPP TS 08.08.
Layer 3 call control messages will as far as possible pass transparently through the BSS. The discrimination between BSSMAP and DTAP messages is detailed in Technical Specification 3GPP TS 08.06.