, Telecom Tigers: Normal Prepaid (IN) Call Flow

Saturday, April 14, 2012

Normal Prepaid (IN) Call Flow

Hi All,

      As Prepaid Call Flow with MNP is already posted, but still many of our friends ask us for detailed Normal Prepaid (IN) Call scenario, so here you go,




The above flow describes a basic direct dial call scenario with normal call termination:

1. Mobile A starts a new call by dialing Mobile B. 

2. The MSC sends an IDP (Initial Detection Point) event, which notifies the IN-SCP of the new call.
  IDP Message Contains :- A-Party no, B-Party no., Service key=90, A Party Location, Time stamp.
3. The IN SCP processes the request and after authorizing the user, the IN SCP sends 3 IN messages to the MSC - 
  • AC (Apply Charging) :-  Check the A-Party Balance / tariff related facilities & provides maximum granted time for a call.
  • CIQ (Call Information Query) :- IN request from the MSC for call information, like CAET - Call Attempt Elapsed Time (time between call ringing & user picks the call), CCET - Call Connect Elapsed Time (Duration of a call), CST - Call Stop Time (exact time when call disconnect), RC - Release Cause (Exact release cause due to which call got disconnected).
  • RRBCSM (Request Report Basic Call State Module) :- IN again request from MSC for detailed Release Cause.
4. Connect :- After getting everything OK i.e. all request from IN side have been done then IN sends a Connect message to MSC for further call processing & connect the call.

5. Activity Test :- After IN provides "connect" message to MSC, its a sort of ping message which is unidirectional, sent by IN to MSC, to know the progress of a call.

6. Once the connection is made, an event report (for answer event) is sent to SDP via IN-SCP.for preventing any revenue loss.

7. After conversation, when call gets disconnected, a new event report is sent to SDP via IN-SCP, which in turn instructs to release the call.

8. Once the call is released, a new Apply Charging Report (ACR) is sent to IN-SCP, which contains full time usage data of a call. This report is sent to SDP for accurate & final call charging.

9. CIR (Call Information Report) :- By using the details which was noted in CIQ message, MSC makes a report i.e. CIR (which contains CAET, CCET, CST, RC) & sends to SDP via IN-SCP.

10. ERB (Evert Report BCSM) :- Another report send by MSC to IN, which contains actual release cause in details, which may be - Abandon, B-Party Busy, B-Party no answer, B-Party not reachable, route selection failure, disconnect.

11. Finally signaling terminates, which ends the call. 


Keep checking for new posts till then HaPPy Reading.
Comments are most Welcomed.

ChEeEeEeRrRrRs
Telecom Tigers Team 
telecomtigers@gmail.com
http://homepageforu.webs.com/
 


2 comments:

  1. Nice post & reasonably old post ! However, I think its about time that we start throwing in more conditions...e.g. what happens to signaling of ongoing prepaid call when there is a parallel operation of inter-MSC handover ?!
    What happens to the CDR information on SCP & MSC ?!

    ReplyDelete
  2. Hello Sir,

    Today only i came across your blog and i think i am in right place as telecom engineer.

    Full form of SCP and SDP is not mentioned here.how can i get to know.

    ReplyDelete

 
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