Extreme Networks ExtremeWare XOS 11.1, Руководство пользователя

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Quality of Service
ExtremeWare XOS 11.1 Concepts Guide
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A QoS profile switch does not alter the behavior of the switch until it is assigned to a traffic grouping.
The default QoS profiles cannot be deleted. The settings for the default QoS parameters on the Aspen
8810 switch are summarized in
Table 31 .
QoS Profiles on the BlackDiamond 10K Switch
The BlackDiamond 10K switch has 8 hardware queues for each egress port. The QoS profiles, QP1 to
QP8, map to these hardware queues.
A QoS profile on the BlackDiamond 10K switch defines a class of service by specifying traffic behavior
attributes, such as bandwidth. The parameters that make up a QoS profile on the BlackDiamond 10K
switch include:
●
Minimum bandwidth—The minimum total link bandwidth that is reserved for use by a hardware
queue on a physical port (each physical port has eight hardware queues, corresponding to a QoS
profile). The minimum bandwidth value is configured either as a percentage of the total link
bandwidth or using absolute committed rates in Kbps or Mbps. Bandwidth unused by the queue can
be used by other queues. The minimum bandwidth for all queues should add up to less than 100%.
The default value on all minimum bandwidth parameters is 0%.
●
Maximum bandwidth—The maximum total link bandwidth that can be transmitted by a hardware
queue on a physical port (each physical port has eight hardware queues, corresponding to a QoS
profile). The maximum bandwidth value is configured either as a percentage of the total link
bandwidth or using absolute peak rates in Kbps or Mbps. The default value on all maximum
bandwidth parameters is 100%.
●
Priority—The level of priority assigned to a hardware egress queue on a physical port. There are
eight different available priority settings and eight different hardware queues. By default, each of the
default QoS profiles is assigned a unique priority. You use prioritization when two or more hardware
queues on the same physical port are contending for transmission on the same physical port, only
after their respective bandwidth management parameters have been satisfied. If two hardware
queues on the same physical port have the same priority, a round-robin algorithm is used for
transmission, depending on the available link bandwidth.
■
When configured to do so, the priority of a QoS profile can determine the 802.1p bits used in the
priority field of a transmitted packet (see
“Replacing 802.1p priority information” on page 210 ).
■
The priority of a QoS profile determines the DiffServ code point value used in an IP packet when
the packet is transmitted (see
“Replacing DiffServ code points” on page 213 ).
A QoS profile does not alter the behavior of the switch until it is assigned to a traffic grouping. Recall
that QoS profiles on the BlackDiamond 10K switch are linked to hardware queues. There are multiple
hardware queues per physical port. By default, a QoS profile links to the identical hardware queue
across all the physical ports of the switch.
Table 31: Default QoS profile parameters on the Aspen 8810 switch
Profile Name Priority Buffer Weight
QP1 Low 100% 1
QP8 High 100% 1