Question: In UMTS networks, what happens when the source RNC expects but does not receive a RANAP RELOCATION COMMAND or RELOCATION PREPARATION FAILURE message for 'Failed relocation preparations with UE not involved for PS domain'?
Option 1: The event is ignored and not counted in any failure cause.
Option 2: It is added to a 'No Reply' measurement cause, in addition to predefined failure causes.
Option 3: The source RNC re-sends the RELOCATION REQUIRED message after a timeout.
Option 4: The failure is attributed to a generic 'Unknown Cause' category.
Explanation: When expected RANAP messages are not received by the source RNC, these instances are counted under a 'No Reply' measurement cause, in addition to predefined failure causes, for comprehensive network performance monitoring, especially in PS domain scenarios without UE involvement.