Question: What is the primary purpose of Border Control Functions in the context of IP Multimedia Subsystem (IMS) as described in telecom standards?
Option 1: To manage interconnection boundaries between IM CN subsystem networks or with other SIP-based multimedia networks, based on operator configuration.
Option 2: To enhance Quality of Service (QoS) for real-time communications within a single IMS network.
Option 3: To provide end-to-end encryption for all SIP signaling and media transfer across different networks.
Option 4: To facilitate the integration of non-SIP based legacy systems into an IMS environment.
Explanation: Border Control Functions are crucial for managing interactions between different networks, ensuring seamless communication while adhering to operator-defined configurations. This is vital for interoperability and security across IM CN subsystem networks and other SIP-based multimedia networks.