Which three protocols assist the WebRTC functionality to overcome the Network Address Translations (NAT) challenges? (Choose three.)

Interactive Connectivity Establishment (ICE) is a framework used to find the most efficient path for media to travel between WebRTC endpoints. To achieve this, ICE utilizes two other protocols. First, it uses Session Traversal Utilities for NAT (STUN) to allow a client to discover its public IP address when it is behind a NAT. If a direct peer-to-peer connection cannot be established (often due to restrictive or symmetric NATs), ICE then uses Traversal Using Relays around NAT (TURN). A TURN server acts as a relay, forwarding media packets between the two endpoints. Together, ICE, STUN, and TURN provide a comprehensive solution to the challenges of NAT traversal in WebRTC.

B. SRTCP: Secure Real-time Transport Control Protocol (SRTCP) provides encryption, message authentication, and integrity for RTCP packets, but it does not facilitate NAT traversal.

D. HTTPS: Hypertext Transfer Protocol Secure (HTTPS) is used for secure signaling (e.g., exchanging session descriptions) to set up the call, not for traversing NATs with the actual media stream.

1. IETF RFC 8445: Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal.

Section 1, Introduction: "ICE is a protocol for NAT traversal for UDP-based media streams... It makes use of the Session Traversal Utilities for NAT (STUN) protocol and its extension, Traversal Using Relays around NAT (TURN)." This statement directly links ICE, STUN, and TURN as the core components for NAT traversal.

2. Avaya Aura® Session Manager 8.1.3 Documentation, Administering Avaya Aura® Session Manager, December 2020.

Page 211, Chapter: Administering Session Manager, Section: WebRTC configuration: "For WebRTC clients to communicate with other endpoints, you must configure a STUN/TURN server. The STUN/TURN server is required for NAT traversal." This official Avaya documentation confirms the necessity of STUN and TURN for WebRTC NAT traversal within the Avaya ecosystem.

3. IETF RFC 8656: Traversal Using Relays around NAT (TURN): Relay Extensions to Session Traversal Utilities for NAT (STUN).

Section 1, Introduction: "If an endpoint is located behind a NAT that prevents a direct connection, the endpoint must use a relay to communicate with its peers. TURN is a protocol that allows an endpoint to obtain IP addresses and ports from such a relay." This defines the role of TURN as a relay mechanism when direct connections fail.

4. IETF RFC 8489: Session Traversal Utilities for NAT (STUN).

Section 1, Introduction: "STUN is a client-server protocol. It can be used by an endpoint to determine the IP address and port allocated to it by a NAT." This specifies STUN's primary function in discovering the public-facing address, a critical first step in NAT traversal.