Alcatel-Lucent 7950 Quality Of Service Manual page 33

Adaptation Rule
The adaptation rule provides the QoS provisioning system with the ability to adapt specific CIR
and PIR defined administrative rates to the underlying capabilities of the hardware the queue will
be created on to derive the operational rates. The administrative CIR and PIR rates are translated to
actual operational rates enforced by the hardware queue. The rule provides a constraint used when
the exact rate is not available due to hardware implementation trade-offs.
For the CIR and PIR parameters individually, the system will attempt to find the best operational
rate depending on the defined constraint. The supported constraints are:
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Depending on the hardware upon which the queue is provisioned, the actual operational CIR and
PIR settings used by the queue will be dependant on the method the hardware uses to implement
and represent the mechanisms that enforce the CIR and PIR rates.
The adaptation rule always assumes that the PIR (shaping parameter) on the queue is the most
important rate. When multiple available hardware rates exist for a given CIR and PIR rate pair, the
PIR constraint is always evaluated before the CIR.
to define the granularity for both the CIR and PIR rates The adaptation rule controls the method
the system uses to choose the rate step based on the administrative rates defined by the rate
command.
QoS Enhancements
The maximum rate configurable for queue PIR and CIR rates in a SAP ingress and egress policy
(when used with SAP or subscribers), and in an ingress and egress queue group, have been
increased to 2000 Gbps.
If the rates at ingress exceed the port capacity, or exceed the FP capacity with per-fp-ing-queuing
configured, the rates are set to max. At egress, if the rates exceed the port capacity (including the
egress-rate setting) they are set to max. As a consequence, the maximum queue rate used can
change and hence the behaviour of some existing configurations can change. This also impacts the
use of percent-rates with no parent or a max-rate parent, or the use of the advanced-config-policy
with a percent percent-of-admin-pir.
Rates greater than the above (capped) rates are only relevant when configured on a queue which is
part of a distributed or port-fair mode LAG spanning multiple FPs.
7950 XRS Quality of Service Guide
Minimum — Find the hardware supported rate that is equal to or higher than the specified
rate.
Maximum — Find the hardware supported rate that is equal to or lesser than the specified
rate.
Closest — Find the hardware supported rate that is closest to the specified rate.
QoS Policies
Page 33