Alcatel-Lucent 7950 Quality Of Service Manual page 70

Frequently Used QoS Terms
greater. If the forwarding requirement for the child is greater than the CIR value, the remaining is
considered to be the above CIR offered load. The sum of the within CIR and above CIR offered
load cannot be greater than the maximum rate defined for the child.
Orphan When a child queue is configured with a parent scheduler specified but the parent scheduler does
not exist on the object the queue is created on, the state is considered orphaned.
An orphaned state is not the same condition as when a queue is not defined with a parent
association. Orphan states are cleared when the parent scheduler becomes available on the object.
This can occur when a scheduler policy containing the parent scheduler name is applied to the
object that the queue exists on or when the scheduler name is added to the scheduler policy already
applied to the object that the queue exists on.
A scheduler becomes a parent when a queue or scheduler defines it as its parent. A queue or
Parent
scheduler can be a child of only one scheduler. When defining a parent association on a child
scheduler, the parent scheduler must already exist in the same scheduler policy and on a scheduler
tier higher (numerically lower) then the child scheduler. Parent associations for queues are only
checked once, when an instance of the queue is created on a SAP.
A queue is where packets that will be forwarded are buffered before scheduling. Packets are not
Queue
actually forwarded through the schedulers; they are forwarded from the queues directly to ingress
or egress interfaces. The association between the queue and the virtual schedulers is intended to
accomplish bandwidth allocation to the queue. Because the offered load is derived from queue
utilization, bandwidth allocation is dependent on the queue distribution among the scheduler
hierarchy. Queues can be tied to only one scheduler within the hierarchy.
The rate defines the maximum bandwidth that will be made available to the scheduler or queue.
Rate
The rate is defined in kilobits per second (Kbps).
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A scheduler that has no parent scheduler association (is not a child of another scheduler) is
Root
(Scheduler)
considered to be a root scheduler. With no parent scheduler, bandwidth utilized by a root scheduler
is dependent on offered load of child members, the maximum rate defined for the scheduler and
total overall available bandwidth. Any scheduler can be a root scheduler. Since parent associations
are not allowed in Tier 1, all schedulers in Tier 1 are considered be a root scheduler.
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On a scheduler, the rate setting is used to limit the total bandwidth allocated to the
scheduler's child members.
For queues, the rate setting is used to define the Peak Information Rate (PIR) at which the
queue can operate.
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