Which statement best describes how a statistical multiplexer differs from a fixed (conventional) multiplexer?

Introduction / Context:
Multiplexing lets multiple sources share one link. In fixed Time Division Multiplexing (TDM), each input gets a time slot whether or not it has data. Statistical multiplexing instead assigns capacity dynamically, based on which inputs have traffic, improving efficiency under bursty loads.

Given Data / Assumptions:

• Fixed (conventional) multiplexers typically allocate resources deterministically (e.g., TDM slots).
• Statistical multiplexers schedule packets/frames opportunistically.

Concept / Approach:
Because many data sources are bursty, fixed slots can be idle, wasting capacity. Statistical multiplexers queue incoming data (hence need buffering) and transmit when the link is available, achieving higher utilization across many sources with independent bursts.

Step-by-Step Solution:

Verification / Alternative check:
Queueing models show utilization gains with independent, bursty sources. Packet networks (e.g., routers) embody statistical multiplexing by forwarding whichever packets are queued, not reserving fixed slots per source.

Why Other Options Are Wrong:

• No buffering: false—statistical multiplexers require buffers to absorb bursts.
• X.25 vs Aloha: protocol pairing here is irrelevant and incorrect.
• TDM vs FDM claim: statistical multiplexing is not defined by FDM; it is about dynamic allocation.
• None of the above: incorrect because the efficiency statement is accurate.

Common Pitfalls:
Assuming statistical multiplexing is the same as priority scheduling; conflating it with specific MAC schemes; believing it guarantees zero loss (buffers can overflow under heavy load).

Final Answer:
Fixed TDM multiplexers may waste link capacity, whereas statistical multiplexers optimize use based on demand