Question: What happens when a mandatory or conditionally required Information Element (IE)/IE group is not included in a received RNSAP message over the Iur interface in UTRAN?
Option 1: The receiver ignores the missing IE/IE group and processes the rest of the message.
Option 2: The receiver sends a request for retransmission of the entire message.
Option 3: An abstract syntax error occurs due to the missing IE/IE group, as per RNSAP specifications.
Option 4: The receiver automatically inserts default values for the missing IE/IE group.
Explanation: According to RNSAP signalling specifications, if an IE/IE group is not included in a received message and its presence is either mandatory or conditional (with the condition being true), it results in an abstract syntax error, ensuring protocol integrity and consistency across network elements.