Just a follow up to all the good points and answers.
A CAMEL user is Serviced Marked in the HLR (or Database) with
a CAMEL Subsription Identity (CSI) flag. This can be Originated (O-CSI)
or Terminated (T-CSI) flag. For O-CSI, CAMEL calls are routed to the
gsmSSF / gsmSCF. In term the respective CAMEL applicaton (e.g. PrePaid)is contacted.
As CAMEL uses the notion of “triggering”. In order to trigger to a control (gsmSCF) a Detection Point (DP) must be used. DP2 is used to collect and analyse the received digits. DP7 is used to monitor the gsmSSF for an answer (Originating-ans) signal.
CAMEL is based on the traditional Intelligent Networks – IN. CAMEL/IN uses a Finite State Machine (FSM) to move the gsmSSF from one state to another in a clear and well defined manner.
Basic call state model (BCSM) is used to describe the actions and different phases of the call processing in the MSC/VLR/GMSC. The BCSM consists of two sets of
call processing logics, i.e., originating BCSM (O-BCSM) and terminating BCSM (T-BCSM).
The DP and points in call are two main components of a BCSM.
For cases where the gsmSCF / SDF cannot be accessed the system can be configured so that
calls can be setup and processed. CDR / DRs can then be collected and processed by a mediation
node. In turn, via CDR processing the accounts in the SDF can be updated.
Please let me know if you need any further inputs.
VBR/ Wallis Dudhnath