Question: For IMS (IP Multimedia Subsystem) media plane firewall traversal, what transport protocols and ports does the IMS client support for communication with a TURN (Traversal Using Relays around NAT) server?
Option 1: UDP on standard port 53 and TCP on non-standard port 8080
Option 2: TLS/TCP on non-standard port 443 and TCP on standard port 21
Option 3: DTLS/UDP on standard port 1194 and TCP on non-standard port 22
Option 4: TLS/TCP on non-standard port 443 and TCP on non-standard port 80
Explanation: For effective firewall traversal in the IMS media plane, the IMS client must utilize protocols and ports that are less likely to be blocked by firewalls while still ensuring security. Supporting TLS/TCP on a non-standard port like 443 (commonly used for HTTPS, thus more likely to be allowed) and TCP on a non-standard port 80 (often used for HTTP, making it more permissible) facilitates this balance. This setup enables secure communication with the TURN server, especially in scenarios involving HTTP proxies, by leveraging commonly accepted ports for secure web traffic.