Question: Under which circumstances is the 'Revoke Authorization for GPRS and IP Resources' procedure typically initiated in a telecom network?
Option 1: Upon successful establishment of a new PDP context for a client handle.
Option 2: When a UE (User Equipment) switches from 4G to 5G networks.
Option 3: During the initial setup of QoS (Quality of Service) for a voice call.
Option 4: Upon session release, session redirection of the last session, or upon receiving a SIP final error response after bearer establishment.
Explanation: The 'Revoke Authorization for GPRS and IP Resources' procedure is designed to free up allocated resources when they are no longer needed. This typically occurs in scenarios such as session release (when a session is terminated), session redirection of the last (or only) session associated with a given client handle (indicating no further need for the allocated resources), or upon receiving a SIP final error response after bearer establishment (signifying an unsuccessful setup that doesn't require sustained resource allocation). This procedure ensures efficient management of network resources.