Tripp Lite NGI-M05-C1, Руководство пользователя, Страница: 68 / 254

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6.1.1.4. Schedule Mode
Queuing Algorithms
Queuing algorithms allow switches to maintain separate queues for packets from each
individual source or flow and prevent a source from monopolizing the bandwidth.

Strict-Priority (SPQ)
The packets on the high priority queue are always service firstly.

Weighted round robin (WRR)
Round Robin scheduling services queues on a rotating basis and is activated only
when a port has more traffic than it can handle. A queue is given an amount of
bandwidth irrespective of the incoming traffic on that port. This queue then moves to
the back of the list. The next queue is given an equal amount of bandwidth, and then
moves to the end of the list; and so on, depending on the number of queues being used.
This works in a looping fashion until a queue is empty.
Weighted Round Robin (WRR) scheduling uses the same algorithm as round robin
scheduling, but services queues based on their priority and queue weight (the number
you configure in the queue Weight field) rather than a fixed amount of bandwidth.
WRR is activated only when a port has more traffic than it can handle. Queues with
larger weights get more service than queues with smaller weights. This queuing
mechanism is highly efficient in that it divides any available bandwidth across the
different traffic queues and returns to queues that have not yet emptied.

Weighted Fair Queuing ( WFQ )
WFQ is a data packet scheduling technique allowing different scheduling priorities to
statistically multiplexed data flows. It provides traffic priority management that
automatically sorts among individual traffic streams without requiring an access list.
WFQ decides which queue is selected in one slot time to guarantee the minimal packet
rate of one queue. Thus, WFQ allows Internet operators to define traffic classes and
then assign different bandwidth proportions.
6.1.1.4.1. CLI Configuration
Node Command Description
enable show qos mode This command displays the current QoS
scheduling mode of IEEE 802.1p.
enable configure terminal This command changes the node to configure
node.
configure qos mode high-first This command configures the QoS scheduling
mode to high-first, each hardware queue will
transmit all of the packets in its buffer before
permitting the next lower priority to transmit its
packets.