Alcatel-Lucent 7950 Quality Of Service Manual page 69

QoS Policies
The CIR level parameter defines the strict level at which bandwidth is allocated to the child queue
CIR Level
or scheduler during the within CIR distribution phase of bandwidth allocation. All committed
bandwidth (determined by the CIR defined for the child) is allocated before any child receives
non-committed bandwidth. Bandwidth is allocated to children at the higher CIR levels before
children at a lower level. A child CIR value of zero or an undefined CIR level results in bandwidth
allocation to the child only after all other children receive their provisioned CIR bandwidth. When
multiple children share a CIR level, the CIR weight parameter further defines bandwidth
allocation according to the child's weight ratio.
The CIR weight parameter defines the weight within the CIR level given to a child queue or
CIR Weight
scheduler. When multiple children share the same CIR level on a parent scheduler, the ratio of
bandwidth given to an individual child is dependent on the ratio of the weights of the active
children. A child is considered active when a portion of the offered load is within the child's
defined CIR rate. The ratio is calculated by first adding the CIR weights of all active children and
then dividing each child's CIR weight by the sum. If a child's CIR level parameter is not defined,
that child is not included in the within CIR distribution and the CIR weight parameter is ignored.
A CIR weight of zero forces the child to receive bandwidth only after all other children at that
level have received their 'within CIR' bandwidth. When several children share a CIR weight of
zero, all are treated equally.
Child Child is a logical state of a queue or scheduler that has been configured with a valid parent
scheduler association. The child/parent association is used to build the hierarchy among the queues
and schedulers.
The level parameter defines the strict priority level for a child queue or scheduler with regards to
Level
bandwidth allocation during the above CIR distribution phase on the child's parent scheduler. This
allocation of bandwidth is done after the 'within CIR' distribution is finished. All child queues and
schedulers receive the remaining bandwidth according to the strict priority level in which they are
defined with higher levels receiving bandwidth first and lower levels receiving bandwidth if
available.
The Maximum Burst Size (MBS) command specifies the relative amount of the buffer pool space
MBS
for the maximum buffers for a specific ingress network forwarding class queue or egress network
port forwarding class queue. The value is entered as a percentage.
MCR The Minimum Cell Rate (MCR).
Offered load is evaluated per child in the scheduler hierarchy. The offered load is the amount of
Offered
Load
bandwidth a child queue or scheduler can use to accommodate the data passing through the child.
It is separated into two portions; within CIR and above CIR. Within CIR offered load is the portion
of bandwidth required to meet the child's CIR value. It can be less than the CIR value but never
7950 XRS Quality of Service Guide Page 69