Question: In a roaming scenario, where is the Serving-CSCF (Call Session Control Function) typically located for a subscriber's Home subscribed services, according to IMS architecture principles?
Option 1: Visited Network
Option 2: Third-Party Service Platform
Option 3: Either Home or Visited Network, depending on the service type
Option 4: Home Network
Explanation: According to IMS principles for supporting roaming users, the Serving-CSCF, responsible for invoking service logic and controlling sessions for Home subscribed services, is located in the subscriber's Home network. This ensures the Home network retains control over services provided to its subscribers even when they are roaming.