Alcatel-Lucent 7450 Quality Of Service Manual page 577

The first pass is called the within-cir pass and consists of providing the available port bandwidth to
each of the 8 priority levels starting with level 8 and moving down to level 1. Each level takes the
offered load and distributes it to all child members that have a port-parent cir-level equal to the current
priority level. (Any child with a cir-weight equal to 0 is skipped in this pass.) Each child may consume
bandwidth up to the child's frame based within-cir offered load. The remaining available port
bandwidth is then offered to the next lower priority level until level 1 is reached.
The second pass is called the above-cir pass and consists of providing the remaining available port
bandwidth to each of the eight priority levels a second time. Again, each level takes the offered load
and distributes it to all child members that have a port-parent level equal to the current priority level.
Each child may consume bandwidth up to the remainder of the child's frame based offered load (some
of the offered load may have been serviced during the within-cir pass). The remaining available port
bandwidth is then offered to the next priority level until level 1 is again reached.
If the port scheduling policy is using the default orphan behavior (orphan-override has not been
configured on the policy), the system then takes any remaining port bandwidth and allocates it to the
orphan queues and scheduler on priority level 1. In a non-override orphan state, all orphans are
attached to priority level 1 using a weight of 0. The 0 weight value causes the system to allocate
bandwidth equally to all orphans based on each orphan queue or scheduler's ability to use the
bandwidth. If the policy has an orphan-override configured, the orphans are handled based on the
override commands parameters in a similar fashion to properly parented queues and schedulers.
The port scheduler priority level command rate keyword is used to optionally limit the total amount of
bandwidth that is allocated to a priority level (total for the within-cir and above-cir passes). The cir
keyword optionally limits the first pass bandwidth allocated to the priority level during the within-cir
pass.
When executing the level command, at least one of the optional keywords, rate or cir, must be
specified. If neither keyword is included, the command will fail.
If a previous explicit value for rate or cir exists when the level command is executed, and either rate
or cir is omitted, the previous value for the parameter is overwritten by the default value and the
previous value is lost.
The configured priority level rate limits may be overridden at the egress port or channel using the
egress-scheduler-override level priority-level command. When a scheduler instance has an override
defined for a priority level, both the rate and cir values are overridden even when one of them is not
explicitly expressed in the override command. For instance, if the cir kilobits-per-second portion of the
override is not expressed, the scheduler instance defaults to not having a CIR rate limit for the priority
level even when the port scheduler policy has an explicit CIR limit defined.
Default no level priority-level
Parameters priority-level — Specifies to which priority level the level command pertains. Each of the eight
pir pir — Specifies the total bandwidth limits allocated to priority-level.
Quality of Service Guide
levels is represented by an integer value of 1 to 8, with 8 being the highest priority level.
Values 1 to 8 (8 is the highest priority)
Values 1 to 3200000000 | max (Kilobits per second (1,000 bits per
second))
QoS Scheduler Policies
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