Which latency component is associated with processing delays at devices?

Which latency component is associated with processing delays at devices?

• A. Propagation delay
• B. Transmission delay
• C. Queuing delay
• D. Processing delay

Answer: (D)

Processing delay is the time a router or switch spends actually handling the packet—reading its header, performing routing lookups, applying policies, recalc­ulating checksums, and deciding the next hop. This delay happens inside the device itself, so it captures the work the hardware or software must do to process the packet. In contrast, propagation delay is the time it takes for a bit to travel from one end of the link to the other, determined by distance and the speed of the medium; transmission delay is the time to push all the packet’s bits onto the link, depending on packet size and link bandwidth; and queuing delay is the time a packet waits in buffers due to congestion. Since the question focuses on delays caused by the device’s own processing work, processing delay is the correct concept.

Processing delay is the time a router or switch spends actually handling the packet—reading its header, performing routing lookups, applying policies, recalc­ulating checksums, and deciding the next hop. This delay happens inside the device itself, so it captures the work the hardware or software must do to process the packet.

In contrast, propagation delay is the time it takes for a bit to travel from one end of the link to the other, determined by distance and the speed of the medium; transmission delay is the time to push all the packet’s bits onto the link, depending on packet size and link bandwidth; and queuing delay is the time a packet waits in buffers due to congestion. Since the question focuses on delays caused by the device’s own processing work, processing delay is the correct concept.