What protocol is standard for IP telephony and video conferencing?

The Session Initiation Protocol (SIP) is the standard protocol specifically designed for managing multimedia communication sessions, including IP telephony and video conferencing. It is responsible for signaling and controlling multimedia communication sessions such as voice and video calls over the Internet. SIP manages the setup, modification, and termination of these sessions, making it essential for real-time communications.

This protocol supports not only voice calls but also video calls and messaging, facilitating the integration of various types of media in a single communication session. By using SIP, devices can communicate efficiently, enabling features such as call routing, user registration, and session management.

The other options, such as HTTP, SMTP, and FTP, serve entirely different purposes. HTTP is used for transferring hypertext documents on the web, SMTP is focused on sending and receiving email, and FTP is used for transferring files between computers. None of these protocols are designed to handle the real-time signaling and control of multimedia sessions, making SIP the appropriate choice for IP telephony and video conferencing.