Overview:
The ISUP OLI (also know as II digits) parameter includes information that is used for carriers to determine the origin of a call. This information gets lost over SIP networks if not inter-worked properly. This feature allows carrying ANSI ISUP OLI Parameter from traditional TDM network into SIP and vice versa.
This information is passed in the From: header of the INVITE message.
Example
From: “Anonymous”<sip:+18182625511@10.10.10.10;isup-oli=00>;tag=95ffcd055e0f78f7d5d397020e89288d63d4
Common ISUP-OLI codes
00 = Ordinary POTS call - not payphone
01 = Party line
02 = ANI Failure
27 = Payphone with network provided coin control
70 = Payphone without network provided coin control
Configuration:
You enable this feature using the SIP From Header Tags Pane. See IMG 1010 - SIP From: Header Tags (10.5.1_ER1 and above) for more details. When this option is enabled, the IMG will include the INFO digits received in the Originating Line Info parameter (OLI) in the IAM message from the SS7 ANSI side into the ISUP_OLI tag in the From Header on the SIP side, and vice versa.
Call Flows:
SS7 to SIP
The following call flow shows where the IMG receives a call setup request from the PSTN/SS7 with the OLIP. With the ISUP-OLI feature this ISUP-OLI parameter will appear in the From header of the INVITE request
SIP to SS7
The following call flow shows where the IMG receives an INVITE with the From Header containing the ‘ISUP-OLI’ tag. With the ISUP-OLI feature, the IMG will send a call setup request to the PSTN/SS7 with the OLI parameter.
