Question: In a Transparent end-to-end Packet-switched Streaming Service (PSS), what is the primary purpose of including the 'SDP-Requested' header with a value of '1' in a PLAY request during a content switch?
Option 1: To specify individual media streams for subscription without an SDP.
Option 2: To request the server to return the SDP, initiate a new session, and begin playback immediately.
Option 3: To inform the server that the client wishes to receive the description and make a switch, allowing for stream selection setup by the server.
Option 4: To signal the end of a streaming session and release all resources.
Explanation: Including the 'SDP-Requested' header with a value of '1' in a PLAY request signals to the server that the client wants to receive the SDP for the new content, enabling the server to initiate a new session, set up relevant media streams, and start playback, facilitating a seamless content switch within a single round trip based on the provided SDP.