SS7 ISUP to SIP Interworking
- Kelli Higdon
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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)
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(Q.1912.5)
Maximum Objects:
One SIP ISUP object per ISUP Group object
Related Topics and Dependencies
Call Flow Diagram
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Field Descriptions (ANSI - Â RFC 3398)
Use the Call Flow diagram above for reference when reading descriptions below.
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 | |
   |    | 180 Ringing | 183 Session Progress | first 180  ACM | second 183  CPG |
183 Session Progress | 183 Session Progress | first 183Â Â ACM | second 183Â Â CPG | ||
Default (RFC 3398) | 183 is not interworked if ACM has been sent | 180 Ringing | 183 Session Progress | first 180  ACM | second  183 is NOT interworked to SS7 side |
183 Session Progress | 183 Session Progress | first 183  ACM | second  183 is NOT interworked to SS7 side | ||
183 is not interworked if ACM hasNOTÂ been sent | 183 Session Progress | Not Applicable | 183 is NOT interworked | ||
Default (RFC 3398) | 183 is not interworked if ACM has 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 Â ACM | |
180 Ringing | 183 Session Progress | first 180 Â ACM Â | second 183 is NOT interworked to SS7 side | ||
183 Session Progress | 183 Session Progress | first 183 Â ACM Â | second 183 is NOT interworked to SS7 side | ||
183 to CPG (progress) If ACM has been sent | 180 Ringing | 183 Session Progress | first 180 Â ACM | second 183 Â CPG | |
Q.1912.5 procedure | 183 to ACM (no indication) If ACM has NOT been sent | 180 Ringing | 183 Session Progress | first 180  ACM | second 183  CPG |
183 Session Progress | 183 Session Progress | first 183 Â ACM | second 183 Â 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.
CPGÂ - 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 / RESÂ - 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)-Â 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.