Alcatel-Lucent 7950 Quality Of Service Manual page 258

Service Egress QoS Policy Forwarding Class Commands
high-prio-only
Syntax high-prio-only percent-of-mbs
no high-prio-only
Context config>qos>sap-egress>policer
Description
This command is used to configure the percentage of the policer's PIR leaky bucket's MBS (maximum burst
size) that is reserved for high priority traffic. While the mbs value defines the policer's high priority violate
threshold, the percentage value defined is applied to the mbs value to derive the bucket's low priority violate
threshold. See the mbs command details for information on which types of traffic is associated with each
violate threshold.
Default high-prio-only 10
Parameters
percent-of-mbs — The percent-of-mbs parameter is required when specifying high-prio-only and is
expressed as a percentage with granularity of 1,000th of a percent.
Values
Default
mbs
Syntax mbs {size [bytes | kilobytes] | default}
no mbs
Context config>qos>sap-egress>policer
Description
This command is used to configure the policer's PIR leaky bucket's high priority violate threshold. The
high-prio-only command is applied to the MBS value to derive the bucket's low priority violate threshold.
For egress, trusted in-profile packets and un-trusted high priority packets use the policer's high priority
violate threshold while trusted out-of-profile and un-trusted low priority packets use the policer's low
priority violate threshold. At egress, in-profile packets use the policer's high priority violate threshold and
out-of-profile packets use the policer's low priority violate threshold.
The PIR bucket's violate threshold represent the maximum burst tolerance allowed by the policer. If the
policer's offered rate is equal to or less than the policer's defined rate, the PIR bucket depth hovers around
the 0 depth with spikes up to the maximum packet size in the offered load. If the offered rate increases
beyond the metering rate, the amount of data allowed above the rate is capped by the threshold. The low
priority violate threshold provides a smaller burst size for the lower priority traffic associated with the
policer. Since all lower priority traffic is discarded at the lower burst tolerance size, the remaining burst
tolerance defined by high-prio-only is available for the higher priority traffic.
The policer's mbs size defined in the QoS policy may be overridden on an sla-profile or SAP where the
policy is applied.
The no form of this command returns the policer to its default MBS size.
Default
None
Parameters
size [bytes | kilobytes] — The size parameter is required when specifying mbs and is expressed as an
integer representing the required size in either bytes or kilobytes. The default is kilobytes. The optional
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7950 XRS Quality of Service Guide