Question: When an Application Server (AS) hosting a Public Service Identity (PSI) originates a request with a Tel URI target identity, what additional step is required before routing the request?
Option 1: Perform Network Domain Security (NDS) authentication
Option 2: Execute ENUM translation to resolve the Tel URI
Option 3: Initiate charging functions via the charging entities
Option 4: Allocate a new S-CSCF for the PSI if one is not assigned
Explanation: When the target identity is a Tel URI, ENUM (Electronic Numbering) translation is necessary to convert the telephone number into a routable IP address. This step is crucial for properly routing the request within the IMS network or towards another network, ensuring the call or session initiation reaches its intended destination.