Question: What is the primary purpose of the Transaction ID in UTRAN Iur interface RNSAP signalling?
Option 1: To differentiate between various UE Contexts within a single procedure.
Option 2: To associate all messages belonging to the same procedure and uniquely identify it among parallel procedures with the same code and initiator.
Option 3: To indicate the priority level of a procedure among multiple ongoing processes.
Option 4: To specify the protocol version used for a particular procedure.
Explanation: The Transaction ID's role is to link messages within a single procedure and distinguish it from other concurrent procedures initiated by the same peer with the same procedure code, ensuring orderly management of multiple simultaneous processes in the UTRAN Iur interface RNSAP signalling context.