Network Queue QoS Policy Command Reference
182 Quality of Service Guide
Special Cases Forwarding Class Queue on Egress Network Port or Channel — For network egress, each
forwarding class is supported by an egress queue on a per network port basis. These
forwarding class-based queues are automatically created once a port or channel is placed in
the network mode. The configuration parameters for each queue come from the applied egress
policy on the network port or channel. Forwarding Class Queue on egress channel applies
only to the 7450 ESS and 7750 SR.
The mbs value is used to calculate the queue’s MBS size based on the total amount buffer
space allocated for the buffer pool on the egress network port or channel. This buffer pool size
will dynamically fluctuate based on the port or channels egress pool size setting.
The total MBS settings for all network egress queues on the port or channel based on the total
percentages can exceed 100 percent. Some over-subscription can be desirable to allow
exceptionally busy forwarding classes more access to buffer space. The proper use of CBS
settings will ensure that oversubscribing MBS settings will not starve other queues of buffers
when needed.
Forwarding Class Queue on Ingress XMA or MDA — For network ingress, each forwarding
class is supported by an ingress queue per XMA or MDA. These forwarding class queues are
automatically created once a single port or channel is placed in the network mode on the
XMA/MDA and are removed once all network ports or channels are removed from the XMA/
MDA (defined as access). The configuration parameters for each queue come from the
applied ingress policy under the network context of the XMA or MDA.
The mbs value is used to calculate the queue’s MBS size based on the total amount buffer
space allocated for the network ingress buffer pool on the XMA or MDA. This buffer pool
will dynamically fluctuate based on the sum of all ingress pool sizes for all network ports and
channels on the XMA or MDA.
The total MBS settings for all network egress queues on the port or channel based on the total
percentages can exceed 100 percent. Some over-subscription can be desirable to allow
exceptionally busy forwarding classes more access to buffer space. The proper use of CBS
settings will ensure that oversubscribing MBS settings will not starve other queues of buffers
when needed.
Parameters percent — The percent of buffers from the total buffer pool space for the maximum amount of
buffers, expressed as a decimal integer. If 10 MB is the total buffers in the buffer pool, a value
of 10 would limit the maximum queue size to 1MB (10%) of buffer space for the forwarding
class queue. If the total size is increased to 20MB, the existing value of 10 would
automatically increase the maximum size of the queue to 2MB.
Values 0 to 100
pool
Syntax pool pool-name [create]
no pool pool-name
Context config>qos>network-queue>queue
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