Question: In a PSS (Transparent end-to-end Packet-switched Streaming Service) session, how should a client update the server about changes to the wireless link's quality of service parameters after initial reporting?
Option 1: Via a new SETUP request with updated '3GPP-Link-Char' header
Option 2: Through a dedicated QoS update message outside of RTSP requests
Option 3: By modifying the SDP (Session Description Protocol) content
Option 4: Including the '3GPP-Link-Char' header in a SET_PARAMETER or OPTIONS request
Explanation: According to PSS protocols, for changes in wireless link quality of service parameters after initial setup, the client must inform the server using existing RTSP mechanisms. This is efficiently done by including the updated '3GPP-Link-Char' header in either a SET_PARAMETER or OPTIONS request, allowing for seamless adaptation without requiring a new session setup.