ISUB Encoding

The ISDN calling party subaddress parameters convey address information of each device in an ISDN network. The ISDN calling party subaddress can now be interworked into the SIP protocol using the isub and isub encoding parameters. By interworking these two parameters, the ISDN calling party subaddress as well as its encoding type can be passed between ISDN and SIP as well as SIP and ISDN. Below is more information pertaining to the interworking of these parameters.

Call Flow Diagrams

SIP to ISDN:

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 ISDN to SIP:

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Mapping isub and isub encoding to ISDN Calling Party Subaddress

isub-encoding value

nsap-ia5 - Indication that the isub parameter value needs to be encoded using IA5 (AFI = 0x50) when translated to an ISUP message

nsap-bcd - Indication that the isub parameter value needs to be encoded using Binary Coded Decimal (BCD) (AFI=0x48)

nsap - Indication that the isub parameter value needs to be encoded using the encoding type defined in ISO 8328  other than IA5 (AFI = 0x50) or BCD (AFI=0x48).

Mapping of ISDN Calling Party Subaddress to 'isub' and 'isub encoding' parameters

Call Trace

Call Trace - ISUB ENC SIP to ISDN

Call Trace - ISUB ENC ISDN to SIP

Configuration

The isub encoding parameter is a field added to the SIP From Header Tags object. The From Header Tags object is configured under the SIP Profile object and is eventually inserted into a external network element object. Below are instructions on how to configure the isub encoding parameter for interworking between ISDN and SIP.

Initial Configuration

Before configuring, the IMG 2020 must have an initial configuration created on it. Follow the Basic Configurations procedure before proceeding onto configuring the ISUB Encoding feature. 

Create SIP Profile (SGP) and enable ISUB Encoding

Create a SIP SGP object. Under the SIP SGP object, the ISUB Encoding can be configured.

• Create a SIP Profile. Right click on the Dialogic object and select New Profiles. The Profiles object is a parent or container object and no configuration is needed here.

• Right click on the 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 Profiles object just created again and select New SIP Profile. Either enter a Name into the name field that identifies this profile or accept the default entry.

• Right click on the SIP Profile object just created and select New SIP From Header Tags. By default, the ISUB Encoding field is set to Disable. Select enable from the drop down menu from the ISUB Encoding field. For information on how to configure each of the individual fields in the object, refer to the SIP Profile - From Header Tags topic.

Create SIP signaling stack

• Right click on the IMG 2020 physical node and select New Signaling.  The Signaling object is a parent or container object and no configuration is needed here. Refer to the Signaling topic for more information on this object.

• Right click on the Signaling object created and select New SIP. In the IP Address field, select from the drop down menu which IP address will be used for SIP signaling. Refer to IMG 1010 - SIP Signaling Object topic for more information.

Create SIP Channel Groups

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

• Right click on Routing Configuration and select New Channel Groups. The Channel Groups object is a container object also and no configuration is needed. Refer to the Channel Groups topic for more information.

• Right click on Channel Groups object and select New Channel Group. Either enter a name that identifies this channel group or accept the default entry. In this example the Channel Group was labeled SIP_ISUB_ENC_ChGrp.

• Select SIP from the drop down menu of the Signaling Type field. Refer to Channel Group topic for more information on configuring this object.

Create an External Gateway

The SIP Channel group needs to communicate withe an external SIP entity. Create an external network element and then an external gateway that the SIP channel group will transmit messages to. Follow procedure below 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 SIP_ISUB_ENC_GW

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Insert SIP External Network Element into SIP Channel Group:

Right Click on the SIP Channel group created and select New IP Network Element. Within the IP Network Element field, select from drop down menu, the gateway created. See screen capture below.

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• Click on the Channel Groups object again. The Channel Groups object will have a yellow exclamation point in place of the icon indicating the configuration has not been sent to the IMG 2020. Click on the Download Resource Tables button and the new configuration will be sent to the IMG 2020.

• At this point the feature has been configured and enabled. Routing and Translations can now be configured.

Additional Information

None