In Intelligent Network and CAMEL switching, a BCSM is a Basic Call State Model.
Types O-BCSM (Originating BCSM) T-BCSM (Terminating BCSM) A fundamental concept for IN control is the basic call state model (BCSM). When a call is processed by an exchange, the call goes through a number of pre-defined phases. These phases of the call are described in the BCSM. The BCSM generally follows the ISUP signalling of a call
State machine description In the following IN BCSMs, bold Detection Points and Points In Call are also present in the CAMEL Ph1 subset.
TODO: Expand to Ph2,3,4
O-BCSM Points in call 1. O_Null & Authorize Origination Attempt 2. Collected_info (Merged with 1. in CAMEL Ph1) 3. Analyze_Info 4. Routing & Alerting (Merged with 3. in CAMEL Ph1) 5. O_Active 6. O_Exception
Detection Points 1 Origination_Attempt_Authorized 2 Collected_Info 3 Analyzed_Info (this is the only Statically armed DP, others are dynamically armed using "Request Report BCSM (RRBE)" message by the SCP) 4 Route_Select_Failure 5 O_Called_Party_Busy 6 O_No_Answer 7 O_Answer 8 O_Mid_Call 9 O_Disconnect 10 O_Abandon
T-BCSM Points in call 7. T_Null & Authorize Termination_Attempt 8. Select_Facility & Present_Call 9. T_Alerting (Merged with 8. in CAMEL Ph1) 10. T_Active 11. T_Exception
Detection Points 12 Termination_Attempt_Authorized 13 T_Called_Party_Busy 14 T_No_Answer 15 T_Answer 16 T_Mid_Call 17 T_Disconnect 18 T_Abandon
Messages
Initial Detection Point (IDP) RRBE (Request Report BCSM) Event Report BCSM (ERB) Connect (CON) Continue (CUE) Send Charging Information (SCI) ACH (Apply Charging) ACR (Apply Charging Report)
References