Shared-Queue QoS Policies
Quality of Service Guide 661
queue queue-id [queue-type] [multipoint] pool pool-name
no queue queue-id
Context config>qos>shared-queue
Description This command creates the context to configure a shared queue QoS policy queue.
Explicit definition of an ingress queue’s hardware scheduler status is supported. A single ingress queue
allows support for multiple forwarding classes. The default behavior automatically chooses the
expedited or non-expedited nature of the queue based on the forwarding classes mapped to it. As long
as all forwarding classes mapped to the queue are expedited (nc, ef, h1 or h2), the queue is treated as
an expedited queue by the hardware schedulers. When any non-expedited forwarding classes are
mapped to the queue (be, af, l1 or l2), the queue is treated as best effort (be) by the hardware schedulers.
The expedited hardware schedulers are used to enforce expedited access to internal switch fabric
destinations.
On the 7450 ESS, the expedited hardware schedulers are used to enforce expedited access to internal
switch fabric destinations. The hardware status of the queue must be defined at the time of queue
creation within the policy.
The pool keyword is a create time parameter that allows the queue to receive buffers from an explicit
buffer pool instead of the default buffer pool. The specified pool-name must have been explicitly
created in a named-pool-policy and the policy must have been applied to the XMA or MDA or port on
which the queue resides.
If the specified pool-name does not exist on the XMA or MDA, the queue will be treated as ‘pool
orphaned’ and will be mapped to the appropriate default pool. Once the pool comes into existence on
the XMA or MDA or port, the queue will be mapped to the new pool.
Once the queue is created within the policy, the pool command may be used to either remove the queue
from the pool, or specify a new pool name association for the queue. The pool command does not
appear in save or show command output. Instead, the current pool name for the queue will appear (or
not appear) on the queue command output using the pool keyword.
Parameters queue-id — The queue-id for the queue, expressed as an integer. The queue-id uniquely identifies
the queue within the policy. This is a required parameter each time the queue command is
executed.
Values 1 to 32
queue-type — The expedite, best-effort and auto-expedite queue types are mutually exclusive to
each other. Each defines the method that the system uses to service the queue from a hardware
perspective. While parental virtual schedulers can be defined for the queue, they only enforce
how the queue interacts for bandwidth with other queues associated with the same scheduler
hierarchy. An internal mechanism that provides access rules when the queue is vying for
bandwidth with queues in other virtual schedulers is also needed. A keyword must be
specified at the time the queue is created in the SAP ingress policy. If an attempt to change
the keyword after the queue is initially defined, an error is generated.
expedite — This keyword ensures that the queue is treated in an expedited manner
independent of the forwarding classes mapped to the queue.
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