[Arun Kumar]

Hi All,
IM working in GSM Network and would like to know how the SMSC Server(Logica),DBP,EMM,SDP,SCP,and the MSC ,IN are connected internally. How does the SMS flow from these systems.
And how does the charging happen for a Perpaid Subscriber.

[wallis dudhnath]

At the time of writing (2019) the use of Flow Based Charging (FBC) is a well proven way to charge for
VAS / OTT (Value Added Services / Over The Top) Services. Examples of VAS services is SMS, MMS, RBT, CRBT,

etc.. and examples of OTT: Facebook (FB), WhatsApp, WeChat, Netflix, etc.. The solution will use a PCEF, PCRF,

SPR and integration to a Prepaid platform.

IN – Intelligent Network – is the accepted way to implement Prepaid solutions for Voice, VoLTE, ViLTE and Data

Services (via Gy / Gx / Sy).

At the MSC/VLR/(gsm)SSF a detection point (DP) is used to determine if the session (Voice / Data) will need
to be “triggered” to the SCP (Service Control Point). In turn, the SCP will have a tight integration to a
an Account Balance Database / Rating Engine. Between the MSC/VLR (gsm)SSF and the SCP (SCF) an IN interface,

e.g. INAP, CAP (Camel Application Part), etc.. is used. The SDP (SDF) is the IN database that is used to store
the Account / Balance information and the Rating Engine.

To handle SMS the IN interface (e.g. INAP, Local variant of INAP, CAP V3 (CAMEL Application Part), etc..)
is used between the MSC/VLR (gsm)SSF and the IN platform ( SCP ((gsm)SCF)), SDP (SDF), IP (SRF), etc..).

Once a SMS message is submitted it is stored in the local SMS-SC. The MSC/VLR (gsm)SSF will initiate a
query to the Prepaid platform so that a Balance check and a charge (via Rating) can be derived. After this

process the SMS-SC initiates the process to deliver (store / forward) the SMS message.

Looking at your components you have: SMSC Server(Logica),DBP,EMM,SDP,SCP and MSC.
Breaking this down you have:-

SMS-SC: Logica

EMM (Mediation): This is used to extract and process Event Data Records (EDRs) from the MSC/VLR (gsm)SSF,

SMS-SC, SDP and, where appropriate, the SCP.

SDP: Service Data Point that maintains the Account / Balance information. It supports a Realtime Rating

Engine.

SCP ((gsm)SCF) is the Service Control point and is basically the gateway to the SDP (SDF)

VBR/ Wallis Dudhnath

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