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

Signaling System 7 GSM standard {{telephony-stub