IMG 1010 - ISDN Facility Tunneling in SIP INFO

Feature F-5670 ISDN Facility Tunneling functions only after a call between ISDN and SIP is in the answered state. Once a call is in the answered state, the SIP INFO message can be used to transfer information from the SIP network, through the IMG and then to the ISDN network. Once the IMG receives the SIP information it looks for a proprietary header labeled X-DLGCIsdnTunnelingInfo in the format displayed below:

The content of the header must have 0x621c for the IMG take the message and interwork it into the ISDN leg of the call. If the first four bytes are not 0x621c the SIP INFO message will be ignored. Feature 5670 functionality is specifically used to transfer Malicious Call Trace information from SIP to ISDN. Refer to the information below.

Call Flow Diagrams

SIP to ISDN Call Flow

Open

ISDN to SIP Call Flow

Open

Configuration

Before being able to configure ISDN Facility Tunneling in SIP INFO message feature, the following objects must first be configured:

• IMG 1010 - Logical IMG

• IMG 1010 - Physical IMG

• IMG 1010 - Configuring T1 or E1 Bearer Profile - 10.5.x

• IMG 1010 - IP Bearer Profile

• IMG 1010 - IP Network (Interface)

• IMG 1010 - Configuring T1 or E1 Bearer Spans - 10.5.x

• IMG 1010 - VoIP Resource

• IMG 1010 - Channel Group (ISDN)

• IMG 1010 - ISDN D Channel

• IMG 1010 - ISDN Circuits

Configure these initial objects before proceeding to the procedure below.

Create SIP SGP and  SIP Headers objects

Configure SIP Header object to enable X-Dialogic ISDN Data field. Once configured, any SIP messages with the correct SIP proprietary header will be interworked to ISDN side facility message

• Right Click on the Profiles object and select New SIP SGP. Once SIP SGP pane is created, change the SIP Profile ID to something other than 0 by selecting a different ID from the drop down menu. This will allow user to edit the SIP SGP Profile. Refer to IMG 1010 - SIP Profile - 10.5.3 topic for more information on configuring this object.

• Right Click on the SIP SGP object and select New SIP Headers. In the SIP Headers object that appears enable the X-Dialogic ISDN Data field. See screen capture below. Refer to IMG 1010 - SIP Headers topic for more information.
  
  

Create SIP Signaling Stack

Configure the SIP signaling stack on the IMG.

Right click on the Signaling object and select New SIP. Refer IMG 1010 - SIP Signaling Object to the topic for more information on configuring this object. 

Create SIP Channel Group

Right click on Channel Groups object and select New Channel Group. Set the Signaling Type field to SIP and enter a name for this channel group. Refer to IMG 1010 - Channel Group topic for more information on configuring a SIP Channel Group. 

Create External SIP Gateway

The gateway being created is the network element on the SIP network that the SIP INFO message will be coming from.

• Right click on IMG EMS and select New External Network Elements. No configuration is accomplished here. The External Network Element pane is a parent object to multiple external entities in the network. Refer to IMG 1010 - External Network Elements topic for more information.

• Right click on the External Network Elements object and select New External Gateways. Again, no configuration is accomplished here. Refer to IMG 1010 - External Gateways object for more information.

• Right click on External Gateways object and select New External Gateway. Enter a name to identify this gateway, modify the Gateway Signaling Protocol field to display SIP, and enter an IP address in the Gateway IP Address field.

• Within the SIP Profile field select the SIP SGP created above for the X-Dialogic ISDN Data feature. See screen capture below. Refer to the IMG 1010 - External Gateway topic for more information.
  
  

Point SIP Channel group to gateway created

The SIP Channel group created above must point to the external gateway just created.

Right Click on the SIP Channel group created above and select New IP Network Element. In the IP Network Element field, select from drop down menu the gateway created above. Refer to the IMG 1010 - IP Network Element topic for more information on this object. See screen capture below

Route SIP Channel group to ISDN Channel group

At this point the feature has been configured and both the ISDN and SIP channel groups have been configured. Using routing information, route the SIP channel group to the ISDN channel group.

Additional Information

• Call must be in the answered state for the feature to function.

• The ISDN Facility Tunneling is supported in a SIP to ISDN call flow only.

• The ISDN Facility Tunneling is supported for Malicious Call Tracing information only.

• The ISDN Facility Tunneling is supported in all ISDN variants.

• The Proprietary Header the IMG receives on the SIP side must contain the format X-DLGCIsdnTunnelingInfo: 621c<xxxxx>

  • If the Proprietary Header is received but the data does not validate (e.g first two bytes are not 0x621c or length is incorrect) the INFO message will be ignored and the IMG will return a 400 Bad Request [BAD-X-DLGCIsdnTunnelingInfo] response.