Which queueing method processes packets in the order they are received with no prioritization?

Which queueing method processes packets in the order they are received with no prioritization?

• A. FIFO
• B. RED
• C. WFQ
• D. WRED

Answer: (A)

The main idea here is how a queue decides which packet to send next. FIFO stands for First-In, First-Out, meaning each packet is placed at the end of the queue when it arrives and is served from the front in exactly that order. There’s no prioritization or reordering—every packet waits its turn based on arrival, so the processing preserves the sequence they came in. The other options don’t set this strict, arrival-based ordering. RED and WRED are congestion-avoidance/drop policies: they decide when to drop packets based on queue length or thresholds rather than changing the service order. WFQ (Weighted Fair Queuing) uses weights to allocate service among multiple flows, which can interleave packets from different sources and thus not preserve a simple arrival order. So FIFO is the one that guarantees processing strictly in the order received, with no prioritization.

The main idea here is how a queue decides which packet to send next. FIFO stands for First-In, First-Out, meaning each packet is placed at the end of the queue when it arrives and is served from the front in exactly that order. There’s no prioritization or reordering—every packet waits its turn based on arrival, so the processing preserves the sequence they came in.

The other options don’t set this strict, arrival-based ordering. RED and WRED are congestion-avoidance/drop policies: they decide when to drop packets based on queue length or thresholds rather than changing the service order. WFQ (Weighted Fair Queuing) uses weights to allocate service among multiple flows, which can interleave packets from different sources and thus not preserve a simple arrival order. So FIFO is the one that guarantees processing strictly in the order received, with no prioritization.