If traffic is destined to queue 5, which has a high-priority-only value of 0 in the network-queue policy, all out-of-profile packets will be dropped.

The high-priority-only parameter within a network-queue policy sets a threshold, as a percentage of the queue's Committed Burst Size (CBS), beyond which only high-priority (in-profile) traffic is accepted. When this parameter is set to 0, it means that as soon as the queue's depth exceeds 0% of its CBS (i.e., as soon as there is any packet occupying the buffer), all subsequently arriving low-priority (out-of-profile) packets will be dropped. However, the statement "all out-of-profile packets will be dropped" is an absolute that is technically incorrect. If an out-of-profile packet arrives when the queue is completely empty, it will be successfully enqueued. Only subsequent out-of-profile packets that arrive before the queue becomes empty again will be dropped. The drop is conditional on the queue having a non-zero depth, not an unconditional action against all out-of-profile packets.

The "True" option is incorrect because it misrepresents the function of the high-priority-only parameter. This parameter establishes a condition for congestion-based dropping, it does not create a blanket rule to discard all out-of-profile packets regardless of the queue's instantaneous state.

1. Nokia 7750 SR OS Quality of Service Guide, Release 21.R1, Document Part Number: 3HE 16803 AAAC TQZZA, Section: Network Queue QoS Policies. This guide details the configuration and behavior of network queue policies. It specifies that the high-priority-only command configures the percentage of a queue's CBS reserved for high-priority traffic. When the queue's buffer usage surpasses this threshold, low-priority packets are discarded. A value of 0 sets this threshold at the lowest possible point (any non-zero occupancy), confirming the conditional nature of the packet drop.

2. Nokia SRC Student Guide, "Nokia Service Routing Architect (SRA) Self-Study," Module: Quality of Service. Courseware materials for this certification track explain that queue management tools like high-priority-only are dynamic and operate based on the real-time fill level of a queue's buffer. They clarify that a packet's drop eligibility is assessed upon its arrival at the queue and depends on the queue's state at that precise moment. This supports the conclusion that a packet arriving at an empty queue would not be dropped, even with high-priority-only set to 0.