Question: In a circuit switched multimedia telephony service using 3GPP specifications, what is a key implication of Level 1 framing not guaranteeing data transparency, unlike HDLC framing?
Option 1: It necessitates the use of error-correction codes in all MUX-PDU payloads.
Option 2: Resynchronization techniques are never required for decoding MUX-PDUs.
Option 3: Achieving data transparency relies on constructing the MUX-PDU header to prevent flag emulation, otherwise requiring resynchronization upon errors.
Option 4: It mandates a switch from 16-bit flags to 32-bit flags for enhanced reliability.
Explanation: This option correctly captures the essence of Level 1 framing's impact on data transparency. Unlike HDLC, which guarantees data transparency, Level 1 does not. However, by carefully constructing the MUX-PDU header to avoid emulating Level 1 framing flags, transparency can be achieved through correct decoding. If errors occur in the header, resynchronization techniques must be applied, highlighting the conditional nature of achieving transparency with Level 1.