N2 DSG-SCP

Overview

The DSG-SCP Application is responsible for handling CAMEL/INAP call-session control under the direction of a Diameter-capable Online Charging Server (OCS). Communication with the OCS is via an N2SVCD DiameterApp which manages the Diameter transport layer. Communication with the CAMEL Mobile Switching Centre (MSC) or INAP Service Switching Point (SSP) is via an N2SVCD SigtranApp which manages the TCAP/SIGTRAN transport layer.

Interaction may also include announcements with the support of an INAP-capable Specialized Resource Platform (SRP) either on-switch using the INAP/CAMEL ConnectToResource (CTR) operation or external using the INAP/CAMEL EstablishTemporaryResource (ETC) operation.

N2SVCD Components

When deploying the N2DSG-SCP product, the DsgScpApp (Diameter/CAMEL Gateway) application is used as shown in the following component deployment diagram:

See also the general product page for the N2 DSG-SCP.

Traffic Type Determination

Received calls may be for Mobile Originating (MO), Mobile Forwarding (MF), or Mobile Terminating (MT) call legs. Some factors of processing (e.g. Diameter Result-Codes) may be required to take the traffic type into account.

The DSG-SCP applies the following rules, order, to determine the traffic type of a received InitialDP:

1. If the EventTypeBCSM is 12 (termAttemptAuthorized), set the traffic type to MT.
2. If the EventTypeBCSM is 2 (CollectedInfo) or 3 (AnalyzedInformation) and the InitialDP → redirectingPartyID field is present, set the traffic type to MF.
3. If the EventTypeBCSM is 2 (CollectedInfo) or 3 (AnalyzedInformation), set the traffic type to MO.

The call type may be used within selector rules as required.

Subscriber Selection

For each traffic type, the value of the subscriber MSISDN for insertion into the Diameter Subscription-Id → Subscription-Id-Data and/or Subscription-Id-Extension AVPs is set from the InitialDP as follows:

• MO: set from normalised InitialDP → callingPartyNumber.
• MF: set from normalised InitialDP → redirectingPartyID.
• MT: set from normalised InitialDP → calledPartyNumber.

Refer to the DSG-SCP configuration for further details.