H.2 Interworking ISUP to SIP

29.1633GPPInterworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networksTS

The ISUP IAM OLI parameter shall be used to set the "oli" URI parameter within tel URI or the userinfo part of SIP URI with user="phone" parameter (as defined in clause 7.2A.12 of 3GPP TS 24.229 [9]) of a P-Asserted-Identity header in the initial INVITE request. In case the ISUP IAM OLI parameter is absent then the P-Asserted-Identity URI "oli" parameter shall be omitted from the initial INVITE request.

Annex I (normative):
GTT interworking between the IP Multimedia Core Network (CN) Subsystem (IMS) and Circuit Switched (CS) networks