What are the two main components of SIP architecture?

The correct answer, which identifies the two main components of SIP architecture, is "User Agents and SIP Servers."

In the context of SIP (Session Initiation Protocol), User Agents play a crucial role as they act as the endpoints in a SIP communication system. A User Agent can be either a User Agent Client (UAC), which initiates requests to establish sessions, or a User Agent Server (UAS), which responds to those requests. This dual functionality is essential for managing SIP communications, as it allows for the initiation and handling of calls, presence information, and other session-related data.

On the other side, SIP Servers serve as intermediaries that process requests from User Agents. They can perform functions such as routing SIP messages, handling registrations, and enforcing policies related to call handling. Common examples include Proxy Servers, Registrar Servers, and Redirect Servers, each serving specific roles within the SIP infrastructure.

The combination of User Agents and SIP Servers creates a comprehensive architecture that enables robust communication and session management in VoIP systems, making it the foundational structure of SIP.

Other options like Clients and Servers broadly refer to components of networking but do not capture the specialized roles within SIP. End points and Gateways are concepts relevant to communication sessions but are not specific to