P-Asserted-Identity Header Handling

1. The Oracle Communications Unified Session Manager inserts a P-Asserted-Identity header into all messages other than the REGISTER message.
2. When the P-Preferred-Identity header is present in an INVITE sourced by the UE, and the SIP URI contained in this header is also present in the UE's associated URI list, then this SIP URI is inserted in the P-Asserted-Identity header as the SIP message enters the core network.
3. When the P-Asserted-Identity header is present in an INVITE sourced by the UE, and the SIP URI contained in this header is also present in the UE's associated URI list, then the original P-Asserted-Identity header and SIP URI is passed unchanged into the core network.
4. When the From header is present in an INVITE sourced by the UE, and the SIP URI contained in this header appears in the UE's Associated URI list, then this SIP URI is inserted into the P-Asserted-Identity header as the SIP message enters the core network.
5. When the P-Asserted-Identity header is present in an INVITE sourced by the UE, and the SIP URI contained in this header is not present in the Associated URI list, the Oracle Communications Unified Session Manager acts like no P-Asserted-Identity was received from the UE.
6. When no P-Asserted-Identity can be derived from an INVITE sourced by the UE, the P-Asserted-Identity is based on the first URI in the Associated URI list.
7. The P-Asserted-Identity header will be removed from SIP messages sent and received from a UE if either the ingress or egress side is untrusted and the UE’s Privacy header’s contents is id.
8. If no P-Associated-URI exists for a registered endpoint, the Oracle Communications Unified Session Manager will use the configured default P-Asserted-Identity found on the sourcing session agent. This feature works with SIP session agents.
9. If the session agent that originates a message does not include a P-Asserted-Identity header or the request is not originated from the session agent, and the Oracle Communications Unified Session Manager has not received P-Associated-URI list from the registrar for a particular user, no P-Asserted-Identity will be created.
10. The P-Preferred-Identity header will never be passed to the Oracle Communications Unified Session Manager's S-CSCF function.

    If the above steps fail to insert a P-Asserted-Identity header, you can manually configure a value to be inserted into a P-Asserted-Identity header. The ims-access parameter must be enabled on the access SIP interface to use the P-Asserted-Identity header override.