Question: What is a primary function of the Local Inbound/Outbound Proxy in the context of SIP transactions for mission-critical services, aside from routing and forwarding requests/responses?
Option 1: Managing Quality of Service (QoS) for non-IP Multimedia Subsystem (IMS) services
Option 2: Providing NAT traversal to ensure seamless communication across different network types
Option 3: Exclusively handling outbound SIP requests from User Equipment (UE) to the Public Land Mobile Network (PLMN)
Option 4: Overseeing the allocation of IP addresses for incoming mission-critical service users
Explanation: The correct answer, NAT traversal, is crucial for enabling devices behind different types of Network Address Translation (NAT) setups to communicate effectively. This function is vital in heterogeneous network environments, common in modern telecommunications, ensuring that mission-critical services can operate without interruption due to network barriers.