Question: At what points in a SIP session can the originating P-CSCF (Proxy-Call Session Control Function) retrieve network-provided location information based on operator policy?
Option 1: Only upon reception of the SDP answer from the terminating side.
Option 2: Only before sending the INVITE or MESSAGE towards the terminating side.
Option 3: Exclusively at mid-call, triggered by an IP-CAN type change.
Option 4: Either before sending the INVITE or MESSAGE, upon reception of the SDP answer from the terminating side, or at mid-call (e.g., during an IP-CAN type change).
Explanation: This option correctly encompasses all scenarios in which the originating P-CSCF can retrieve network-provided location information based on operator policy, as outlined in the context of telecom network procedures. These scenarios include pre-initial message sending, post-SDP answer reception, and during mid-call events like IP-CAN type changes, highlighting the flexibility and conditional nature of location information retrieval.