Alcatel-Lucent 7950 Quality Of Service Manual 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
Values
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
Values
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
7950 XRS Quality of Service Guide
None, the decrement limit percentage value must be specified when the percent qualifier
is used.
1.00 — 100.00
None, thedecrement limit value must be specified when the rate qualifier is used.
0 — 100,000,000
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