Question: What is a possible outcome when a Radio Network Controller (RNC) utilizes the optional NAS Node Selection Function (NNSF) in a UTRAN architecture?
Option 1: The RNC can only establish a single Iu interface (Iu-CS) towards the CS domain.
Option 2: There may be multiple Iu interfaces established from the RNC, including more than one Iu-CS towards the CS domain and/or more than one Iu-PS towards the PS domain.
Option 3: The NNSF forces the RNC to prioritize PS-domain connections over CS-domain connections.
Option 4: Utilizing NNSF by an RNC mandates a direct connection to the Core Network (CN) without intermediate nodes.
Explanation: When an RNC uses the NAS Node Selection Function (NNSF), it allows for flexibility in connecting to multiple Core Network (CN) nodes. This flexibility enables the setup of more than one interface of each type (Iu-CS for Circuit Switched domain and Iu-PS for Packet Switched domain) from the RNC, enhancing network redundancy and efficiency. This aligns with the principles of intra-domain connection of RAN nodes to multiple CN nodes as per telecom network architecture best practices.