Second P-Asserted-Identity Header for Emergency Calls
The Oracle Communications Unified Session Manager can add a second P-Asserted-Identity header when forwarding an emergency message into the network.
When the UE registers with an S-CSCF, the S-CSCF returns a set of associated URIs, the implicit registration set (IRS,) for the AoR in the 200 OK response. The Oracle Communications Unified Session Manager caches the IRS. The user identities that comprise the cached IRS are used for validation later.
As the Oracle Communications Unified Session Manager receive a UE’s INVITE, the value in the P-Preferred-Identity header is validated against the public user identities in the cached IRS. If the inbound P-Preferred-Identity matches any items in the IRS, the Oracle Communications Unified Session Manager inserts that value into a P-Asserted-Identity header in the egress message. The P-Preferred- Identity header is stripped from the outbound message.
| Inbound INVITE Contains: | Validate Against Implicit Registration Set | Outbound Invite Created With: (all P-Preferred-Identity headers are removed) |
|---|---|---|
| P-Preferred-Identity: value-1 | value-1 present | P-Asserted-Identity: value-1 |
The Oracle Communications Unified Session Manager can create a second P-Asserted-Identity header by configuring the add-second-pai option in the SIP config. Once a combination of SIP URIs and/or TEL URIs in the inbound P-Preferred-Identity header are validated against the IRS, the Oracle Communications Unified Session Manager forwards the emergency INVITEs with two P-Asserted-Identity headers to the E-CSCF. The behavior is based upon the URI type received in the P-Preferred-Identity header and whether those values validate against the IRS list.
| Inbound INVITE Contains: | Validate Against Implicit Registration Set | Outbound Invite Created With: (all P-Preferred-Identity headers are removed) |
|---|---|---|
| P-Preferred-Identity: SIP-URI-1 | SIP-URI-1 present
TEL-URI-1 present (TEL-URI-n present) |
P-Asserted-Identity: SIP-URI-1
P-Asserted-Identity: TEL-URI-1 |
| P-Preferred-Identity: TEL-URI-1 | TEL-URI-1 present
SIP-URI-1 present (SIP-URI-n present) |
P-Asserted-Identity: TEL-URI-1 P-Asserted-Identity: SIP-URI-1 |
| NO P-Preferred-Identity: |
(SIP | TEL) URI -1 present (SIP | TEL) URI -n present |
P-Asserted-Identity: 1st public identity from IRS |
|
P-Preferred-Identity: SIP-URI-1 P-Preferred-Identity: TEL-URI-1 |
TEL-URI-1 present SIP-URI-1 present |
P-Asserted-ID: SIP-URI-1 P-Asserted-ID: TEL-URI-1 |
|
P-Preferred-Identity: SIP-URI-1 P-Preferred-Identity: SIP-URI-2 |
SIP-URI-1 present SIP-URI-2 present TEL-URI-n present |
P-Asserted-Identity: SIP-URI-1 P-Asserted-Identity: 1st TEL-URI from IRS |
|
P-Preferred-Identity: TEL-URI-1 P-Preferred-Identity: TEL-URI-2 |
TEL-URI-1 present TEL-URI-2 present SIP-URI-n present |
P-Asserted-Identity: TEL-URI-1 P-Asserted-Identity: 1st SIP-URI from IRS |
If the INVITE does not include a P-Preferred-Identity header and does not include a P-Asserted-Identity header, or the value in the original P-Preferred-Identity or P-Asserted- Identity header is not contained in the IRS, or the URI from the From: header is not the in the IRS, then default public user identity is inserted into a P-Asserted- Identity header in the egress message. (The default public user identity is the first on the list of URIs in the P-Associated-URI header.)
If the strict-3gpp-pai-compliance option is configured in the outbound SIP interface, the first P-Asserted-Identity header also includes the display name.