Question: What additional protocol, besides HTTP, may be used by a VAE server and service consumer for delivering Notifications, as per 3GPP specifications?
Option 1: Websocket (as defined in IETF RFC 6455)
Option 2: FTP (File Transfer Protocol)
Option 3: SSH (Secure Shell) Protocol
Option 4: SMTP (Simple Mail Transfer Protocol)
Explanation: In the context of VAE services for notifications, besides using a separate HTTP connection, Websocket protocol is also supported for delivering notifications, beneficial for real-time communication and bidirectional data transfer between the VAE server and service consumer.