Diversion and RPID Interworking SIP to SS7 REL

Interworking the Diversion and RPID Headers from SIP to SS7 REL gives a user the ability to control and direct SS7 calls through the use of a SIP Application. When configured, the feature inter-works the Diversion and Remote-Party-Id (RPID) Headers received from the SIP 4xx-Request/Client Failure, 5xx-Server Failure, or 6xx-Global Failure responses into Redirection Information and Generic Number Information in the SS7 REL message. This feature is supported in the ETSI V2 Variant only. See links below for more information.

Call Flow Diagrams

Open

• The originating MSC A sends IAM message with Dialed Number.

• The SS7 message is interworked to SIP and routed to a SIP application.

• Upon reception of the INVITE message, the SIP Application rejects it with a Diversion and Remote Party ID (RPID) Header in the 4xx, 5xx, 6xx failure responses.

• The IMG 2020 inter-works the Diversion Header from SIP into a Redirection Number in the SS7 REL message.

• The IMG 2020 also inter-works the Remote Party ID from SIP into a Generic Number in the SS7 REL message.

• The originating MSC A re-issues the IAM to the Target MSC B using the Redirection Number from the REL message as the Dialed Number and the Generic Number as the Calling Party Number. 

Mapping of Headers

When feature is enabled, the IMG 2020 will map the Diversion Header in SIP failure response message (4xx, 5xx, 6xx) into the SS7 ISUP Redirection Number parameter in the REL message with the following parameter values.

The SIP Remote-Party-ID (RPID) is mapped to the Generic Number as follows

APRI is mapped as follows

Screening Indicator is mapped as follows

Configuration

The SIP Diversion Header to Redirection Number interworking is enabled in the SIP Headers object. The SIP Headers object is created under the SIP Profile object. The Diversion Header Support field must be set to Diversion for the interworking of the SIP Diversion Header to Redirection Number to function as described above.  

The SIP Remote Party ID header to Generic Number interworking is by default always enabled. Any incoming SIP 4xx, 5xx, or 6xx responses with the Remote Party ID Header embedded will be interworked into the Generic Number in outgoing REL message.

Initial Configuration

The procedure below explains how to configure the IMG 2020 to interwork the Diversion and RPID Headers from SIP to SS7 REL. Before configuring, the IMG 2020 must have an initial configuration created on it. Follow the Basic Configurations procedure before proceeding.

Create a SIP Profile (SGP) and then SIP Headers page

• Right click on the Profiles object and select New SIP Profiles. The SIP Profiles object is a parent or container object. No configuration is needed here. Refer to the SIP Profiles topic for more information on this object.

• Right click on the SIP Profiles object and select New SIP Profile. The first profile that gets created is a Default SIP Profile and cannot be modified. Disregard this profile.

• Right click on the SIP Profiles object and select New SIP Profile again. In the SIP Profile object that appears, either enter a name that identifies this SIP Profile or accept the default name already entered. In this example the SIP Profile was labeled SIP_Diversion_RPID_Profile. Refer to the SIP Profile - SGP topic for more information on configuring the remaining fields.

• Right click on the SIP Profile object created and select New SIP Headers. A SIP Headers object will appear. Select Diversion from Diversion Header Support field drop down menu. See below. Refer to SIP Profile - Headers topic for more information on configuring the remaining fields in this object.

Open

Create a External SIP Remote Gateway

Create an external network element and link the SIP profile created with the remote SIP gateway object being configured. Follow procedure below to configure the IMG 2020 to communicate with a remote gateway.

• Right click on the Dialogic object and select New External Network Elements. The External Network Elements object is a parent or container object and no configuration is needed here. Refer to External Network Elements topic for more information.

• Right click on External Network Elements and select New External Gateways. The External Gateways object is a parent or container object also and no configuration is needed here. Refer to External Gateways for more information.

• Right click on External Gateways and select New External Gateway. Enter a name that identifies the gateway being configured. In this example the gateway was labeled DiversionHeader_RPID_GW.

Configure SIP Signaling

The configuration above displays how to configure the SIP Profile and External SIP Gateway so that the SIP Diversion-RPID Header functionality is configured. The next step is to configure the SIP signaling stack and SIP Channel Groups. Refer to the Configure SIP (Single SIP IP) topic for a procedure on how to configure the SIP functionality.

Additional Information

• The feature is supported in the ETSI V2 variant only.

• Interworking for Diversion Header to Redirection Number is enabled by selecting Diversion from drop down menu in the SIP Headers Support field located in the SIP Headers object. Refer to the topic for more information.

• Interworking for Diversion Header to Redirection Number is disabled if either Disable, CC-Diversion, or History-Info is selected in the Diversion Header Support field.

• Interworking for Remote Party ID Header to Generic Number by default is always enabled.