Which protocol is commonly used for providing VoIP services across networks in Avaya solutions?

SIP, or Session Initiation Protocol, is the widely adopted protocol for providing VoIP (Voice over Internet Protocol) services across networks, particularly within Avaya solutions. SIP is specifically designed to enable the initiation, maintenance, and termination of real-time sessions that include voice, video, and messaging applications. This protocol plays a crucial role in establishing the communication sessions by handling the signaling processes, ensuring that calls connect correctly and facilitating the management of multimedia sessions.

In a VoIP environment, SIP is essential because it allows devices to communicate effectively over IP networks, enabling features such as call setup, management, and teardown, making it key to delivering reliable VoIP services.

The other protocols presented—HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), and SMTP (Simple Mail Transfer Protocol)—serve different functions that do not involve direct management of voice communication sessions. HTTP is primarily used for transferring web pages, FTP for file transfers, and SMTP for sending emails. Thus, they are not suitable for the requirements of VoIP services in Avaya solutions, making SIP the correct and relevant choice in this context.