Configure Qos (Quality Of Service) - D-Link DES-3326SR User Manual

DES-3326SR Layer 3 Fast Ethernet Switch User's Guide

Configure QOS (Quality of Service)

The DES-3326SRSR switch supports 802.1p priority queuing.
The switch has 4 priority queues. These priority queues are
numbered from 0 — the lowest priority queue — to 3 — the
highest priority queue. The eight priority queues specified in
IEEE 802.1p (Q0 to Q7) are mapped to the switch's priority
queues as follows:
Q1 and Q2 are assigned to the switch's Q0 queue.
Q0 and Q3 are assigned to the switch's Q1 queue.
Q4 and Q5 are assigned to the switch's Q2 queue.
Q6 and Q7 are assigned to the switch's Q3 queue.
The switch's four priority queues are emptied in a round-robin
fashion—beginning with the highest priority queue, and
proceeding to the lowest priority queue before returning to the
highest priority queue.
For strict priority-based scheduling, any packets residing in the
higher priority queues are transmitted first. Only when these
queues are empty, are packets of lower priority transmitted.
The weighted-priority based scheduling alleviates the main
disadvantage of strict priority-based scheduling − in that lower
priority queues get starved of bandwidth − by providing a
minimum bandwidth to all queues for transmission. This is
accomplished by configuring the maximum number of packets
allowed to be transmitted from a given priority queue and the
maximum amount of time a given priority queue will have to
wait before being allowed to transmit its accumulated packets.
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