Question: In GPRS (General Packet Radio Service), how does the LLC (Link Layer Control) layer handle signaling and SMS transmissions in terms of mode of operation and error handling?
Option 1: Acknowledged mode with protected information transport, ensuring frames with errors are discarded.
Option 2: Unacknowledged mode with an option for both protected (error results in discard) and unprotected (error does not result in discard) information transport.
Option 3: Acknowledged mode with unprotected information transport, allowing frames with errors to pass through.
Option 4: A hybrid mode that switches between acknowledged and unacknowledged based on the type of signaling or SMS message.
Explanation: According to the GPRS service description for LLC transmission modes, signaling and SMS are specifically required to be transferred in unacknowledged mode. Within this mode, the LLC layer offers flexibility by providing options for both protected (where errors lead to frame discard) and unprotected (where errors do not lead to frame discard) information transport, catering to different reliability needs without the overhead of acknowledgment.