SS7 ISUP to SIP Interworking

The IMG 2020 supports SIP to ISUP and ISUP to SIP Interworking that complies with RFC 3398 (ANSI) and Q.1912.5 (03/2004) (ITU-T). The objects below are used when configuring ISUP to SIP interworking. Refer to the SIP to SS7 ISUP Interworking topic if configuring ISUP to SIP. The SIP ISUP IW object configuration allows a customer to decide what message is sent upon receipt of the 183 Session Progress message if they don't want to follow the rules according to RFC 3398 or Q.1912.5 (03/2004) (ITU-T). Use the information below to decide which type of mapping/interworking will be applied.

Web GUI Page

Dialogic > SS7 > SS7 Network > SS7 Stack > SS7 Destination > ISUP Group > New SIP ISUP IW

(RFC 3398)

Open

(Q.1912.5)

Open

Maximum Objects:

One SIP ISUP object per ISUP Group object

Related Topics and Dependencies

SIP to SS7 ISUP Interworking 

Call Flow Diagram

Open

Field Descriptions (ANSI -  RFC 3398)

183 ISUP Mapping Procedure and 183 Mapping Condition

The table below displays the scenarios for both RFC 3398 and Q.1912.5. The first two columns display the settings as displayed in the Web GUI. The 1st and 2nd response columns describe the response the IMG 2020 receives from SIP network and the Mapping of 18x to SIP messaging column displays how the IMG 2020 maps the first and second 18x responses into the SS7 network.

183 ISUP Mapping Procedure	183 Mapping Condition	1st response = 18x	2nd response = 183	Mapping of 18x to SIP messaging
Default (RFC 3398)	Default	180 Ringing	183 Session Progress	first 180  Open  ACM	second 183  Open  CPG
		183 Session Progress	183 Session Progress	first 183  Open  ACM	second 183  Open  CPG
Default (RFC 3398)	183 is not interworked if ACM has been sent	180 Ringing	183 Session Progress	first 180  Open  ACM	second  183 is NOT interworked to SS7 side
		183 Session Progress	183 Session Progress	first 183  Open  ACM	second  183 is NOT interworked to SS7 side
	183 is not interworked if ACM hasNOT been sent	183 Session Progress	Not Applicable	183 is NOT interworked
Default (RFC 3398)	183 is not interworked if ACM has been sent      -and-      183 is not interworked if ACM hasNOT been sent	Don't Care	Don't Care	183 is not interworked. No ISUP messages are sent to SS7 side.

183 ISUP Mapping Procedure	183 Mapping Condition	1st response = 18x	2nd response = 183	SIP SIDE
Q.1912.5 procedure	Default (183 is not interworked)	Don't Care	Don't Care	183 is not interworked. No ISUP messages are sent to SS7 side.
Q.1912.5 procedure	183 to ACM (no indication) If ACM has NOT been sent	183 Session Progress	Not Applicable	183 Open  ACM
		180 Ringing	183 Session Progress	first 180 Open  ACM	second 183 is NOT interworked to SS7 side
		183 Session Progress	183 Session Progress	first 183 Open  ACM	second 183 is NOT interworked to SS7 side
	183 to CPG (progress) If ACM has been sent	180 Ringing	183 Session Progress	first 180 Open  ACM	second 183 Open  CPG
Q.1912.5 procedure	183 to ACM (no indication) If ACM has NOT been sent      -and-      183 to CPG (progress) If ACM has been sent	180 Ringing	183 Session Progress	first 180 Open  ACM	second 183 Open  CPG
		183 Session Progress	183 Session Progress	first 183 Open  ACM	second 183 Open  CPG

Propagate Suspend/Resume

The settings below determine whether the IMG 2020 will send a re-invite message on SIP side when receiving a Suspend/Resume message from ISUP side.

False (Default) - If the IMG 2020 receives a SUSPEND or RESUME message on ISUP side, do not send re-invite message to SIP side.

True - If the IMG 2020 receives a SUSPEND or RESUME message, send a re-invite message to the SIP side.

SIP On Hold

After receiving a Re-INVITE message from the SIP side, the IMG 2020 can put a call on hold by either sending a CPG message or a SUSPEND/RESUME message. Select from drop down menu which message to send to the SS7 side to put a call on hold and then resume the call. Refer to the SIP Call Hold topic for call flow information.

CPG - After call is in an answered state, and after receiving a SIP Re-INVITE message with connection address equal to 0.0.0.0, the IMG 2020 will send a CPG with the notification indicator set to remote hold. When call is to resume, the remote SIP side sends a Re-INVITE with the connection address equal to a valid IP address. The IMG sends a CPG message with the notification indicator set to remote hold released to the remote SS7 ANSI side and the call is released.

SUS / RES - After call is in an answered state, and after receiving a SIP Re-INVITE message with the connection address equal to 0.0.0.0. The IMG 2020 will send a SUSPEND message to put Remote SS7 side on hold. When call is to resume, the remote SIP side sends a Re-INVITE with the connection address equal to a valid IP address. The IMG sends a RESUME message to the remote SS7 ANSI side and the call is released.

Remove Leading 0 in Redirecting Number

During the Interworking of the SIP Diversion Header to the SS7 Redirecting Number, the IMG 2020 can be configured to remove the leading zero from the interworked SS7 Redirecting Number. See below.

Disable (Default)- The leading zero character in the SIP Diversion Header will be interworked to the SS7 Redirecting Number.

Enable - The leading zero character in the SIP Diversion Header will be stripped and NOT interworked into the SS7 Redirecting Number.

Additional Information

• This feature does not affect the logging of the SIP Diversion Header in RADIUS. The Diversion Header is logged in RADIUS with the leading zero regardless of the setting of the Remove Leading 0 in Redirecting Number field.

• When there are multiple Diversion Headers in the SIP INVITE message, the leading zero will be stripped from only the top-most Diversion Header.

• The Remove Leading 0 in Redirecting Number feature should be applied to the outgoing SS7 Channel Group only.

SIP Plus Sign to FCI Call Indicator

Disable (Default)- The FCI parameter in the IAM message is set to National.

Enable - The FCI parameter in the IAM message is set accordingly to the absence/presence on the plus sign in the incoming SIP INVITE.