Interwork Connected Number between SIP and ISDN

The Connected Number parameter is an ISDN parameter found in the Connect message. It is used to implement the Connected Line Identification Presentation (COLP) supplementary service. The Connected Number parameter is sent in the backward direction to identify the number that is connected to a call. Because of potential changes in a call such as call redirection and call transfers, the connected number parameter may be different than the called party number. This feature interworks the connected number parameter between the SIP and ISDN protocols. Refer to the Call Flows below. 

Call Flow Diagrams

SIP to ISDN

In the SIP to ISDN call scenario displayed below, if the Connect message received from the ISDN side includes the Connected Number parameter, the Connected Number parameter will be interworked and added to a new header generated by the IMG 2020 The new header will be added to the outgoing 200 OK message and will use the X-DLGCConnectedInfo custom SIP header format displayed in the Additional Information section below.

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ISDN to SIP

In the ISDN to SIP call scenario displayed below, if the IMG 2020 receives a 200 OK message from the SIP side that includes the X-DLGCConnectedInfo parameter, the Connected Number parameter will be interworked and added to the outgoing Connect message.

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Configuration

Below are instructions on how to configure the IMG 2020 to interwork the Connected Number parameter between SIP and ISDN. Before configuring, the IMG 2020 must have an initial configuration created on it. Refer to the Basic Configurations procedure and verify the basic functionality has been configured. Also, since the feature uses interworking between the SIP and ISDN protocol, verify that ISDN signaling and ISDN channel groups have been configured. Refer to the Configure ISDN topic for information on configuring ISDN.

Enable Mapping of ISDN Connected Number to SIP (Connected Line Identification Presentation)

A SIP Profile is needed to enable this feature and also to use the new X-Dialogic Connected Info private SIP header. Refer to SIP Profile - SGP topic for creating a SIP profile.

• Right click on the SIP Profile object created and select New SIP Headers. In the SIP Headers object that appears, enable the X-Dialogic Connected Info field. See screen capture below. Refer to SIP Profile - Headers topic for more information.
  
  

Additional Information

• A new custom SIP header was created for the SIP leg. The header is displayed below:

• If the X-DLGCConnectedInfo header does not include the noa (nature of address), npi (numbering plan indicator), pi (presentation indicator), or sci (screening indicator) the default values displayed below will be set for the Connected number and sent back to ISDN.

• If the X-DLGCConnectedInfo Header contains non-numeric data as displayed below:

• In a SIP to ISDN call scenario with the feature enabled, if the IMG 2020 receives a message without address signals (any number) in the Connected Number Parameter, the IMG 2020 will not generate and send the X-DialogicConnectedInfo header to the SIP leg.