D-Link DES-3226L, Руководство пользователя

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DES-3226L Layer 2 Fast Ethernet Switch User’s Guide
Configure QoS
The DES-3226L supports 802.1p priority queuing. The switch has two priority queues. These
priority queues are labeled as 0, the high queue, and 1, the low queue. These priority queues,
specified in IEEE 802.1p are mapped to the switch’s priority queues as follows:
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Priority 0 is assigned to the Switch’s Q0 queue.
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Priority 1 is assigned to the Switch’s Q0 queue.
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Priority 2 is assigned to the Switch’s Q0 queue.
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Priority 3 is assigned to the Switch’s Q0 queue.
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Priority 4 is assigned to the Switch’s Q1 queue.
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Priority 5 is assigned to the Switch’s Q1 queue.
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Priority 6 is assigned to the Switch’s Q1 queue.
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Priority 7 is assigned to the Switch’s Q1 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.
For weighted round-robin queuing, the number of packets sent from each priority queue
depends upon the assigned weight. For a configuration of eight CoS queues, A~H with their
respective weight value: 8~1, the packets are sent in the following sequence: A1, B1, C1, D1,
E1, F1, G1, H1, A2, B2, C2, D2, E2, F2, G2, A3, B3, C3, D3, E3, F3, A4, B4, C4, D4, E4,
A5, B5, C5, D5, A6, B6, C6, A7, B7, A8, A1, B1, C1, D1, E1, F1, G1, H1.
For weighted round-robin queuing, if each CoS queue has the same weight value, then each
CoS queue has an equal opportunity to send packets just like round-robin queuing.
For weighted round-robin queuing, if the weight for a CoS is set to 0, then it will continue
processing the packets from this CoS until there are no more packets for this CoS. The other
CoS queues that have been given a nonzero value, and depending upon the weight, will follow
a common weighted round-robin scheme.
Remember that the DES-3226L has two priority queues (and thus two Classes of Service) for
each port on the switch.
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