7950 XRS Quality of Service Guide
Page 561
rate.
A side effect of using a maximum decrement limit is that unused bandwidth allocated to the child queue or
policer will not be given to another child as quickly. This may result in an underrun of the virtual scheduler’s
aggregate rate.
The max-decrement limit has no effect on any increase in a child’s offered rate. If the rate increase is above
the change sensitivity, the new offered rate is immediately used.
If the max-decrement command is used with a percent based value, the decrement limit will be a function of
the configured PIR value on the policer or queue. In this case, care should be taken that the child is either
configured with an explicit PIR rate (other than max) or the child’s administrative PIR is defined using the
percent-rate command with the local parameter enabled if an explicit value is not desired. When a maximum
PIR is in use on the child, the system attempts to interpret the maximum child forwarding rate. This rate
could be very large if the child is associated with multiple ingress or egress ports.
Except for the overall cap on the offered input into the virtual scheduler, the child’s administrative PIR has
no effect on the calculated sensitivity if an explicit rate is specified.
If the child’s administrative PIR is modified while a percent based max-decrement is in effect, the system
automatically uses the new relative maximum decrement limit value the next time the child’s offered rate is
determined.
When the max-decrement command is not specified or removed, the virtual scheduler does not limit a
decreasing offered rate to a specific limit.
The
no
form of this command is used to remove any currently configured maximum decrement limit for all
child policers and queues associated with the policy.
Parameters
percent-of-admin-pir —
When the percent qualifier is used, this parameter specifies the percentage of the
child’s administrative PIR that should be used as the decrement limit to offered rate change. If a value of
100 or 100.00 is used, the system will interpret this equivalent to no max-decrement.
Default
None, the decrement limit percentage value must be specified when the percent qualifier
is used.
Values
1.00 — 100.00
rate-in-kilobits-per-second —
When the rate qualifier is used, this parameter specifies an explicit number of
kilobits-per-second (1000 bits-per-second) that should be as the child’s offered rate change sensitivity
value. If a rate sensitivity of 0 is specified, the system interprets this equivalent to no granularity.
Default
None, thedecrement limit value must be specified when the rate qualifier is used.
Values
0 — 100,000,000
high-rate-hold-time
Syntax
[
no
]
high-rate-hold-time
seconds
[
active-min-only
]
Context
config>qos>adv-config-policy>child-control>offered-measurement
Description
This command sets a time period that the current offered rate should be maintained for a child policer or
queue once it is seen that the offered rate is decreasing. The offered measurement that triggers the hold time
is used when the hold timer expires unless a higher offered rate is seen in the interim. When a higher rate is
Summary of Contents for 7950
Page 12: ...Page 12 7950 XRS Quality of Service Guide List of Figures ...
Page 16: ...Preface Page 16 7950 XRS Quality of Service Guide ...
Page 82: ...Editing QoS Policies Page 82 7950 XRS Quality of Service Guide ...
Page 90: ...Applying Network Queue Policies Page 90 7950 XRS Quality of Service Guide ...
Page 96: ...Editing QoS Policies Page 96 7950 XRS Quality of Service Guide ...
Page 98: ...Command Hierarchies Page 98 7950 XRS Quality of Service Guide ...
Page 108: ...Command Hierarchies Page 108 7950 XRS Quality of Service Guide ...
Page 156: ...Basic Configurations Page 156 7950 XRS Quality of Service Guide exit exit ...
Page 164: ...Queue Depth Monitoring Page 164 7950 XRS Quality of Service Guide ...
Page 304: ...Service Queue QoS Policy Commands Page 304 7950 XRS Quality of Service Guide ...
Page 368: ...Command Hierarchies Page 368 7950 XRS Quality of Service Guide ...
Page 430: ...Configuration Commands Page 430 7950 XRS Quality of Service Guide ...
Page 532: ...Editing QoS Policies Page 532 7950 XRS Quality of Service Guide ...
Page 552: ...Editing Advanced Policies Page 552 7950 XRS Quality of Service Guide ...
Page 600: ...Command Hierarchies Page 600 7950 XRS Quality of Service Guide ...
Page 602: ...QoS Commands Page 602 7950 XRS Quality of Service Guide ...
Page 610: ...Standards and Protocols Page 610 7950 XRS Quality of Service Guide ...
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