Queue Sharing And Redirection - Alcatel-Lucent 7950 Quality Of Service Manual

ers and SAPs. This allows the policy association decision to be ignorant of the type of hardware the SAP or
subscriber is traversing.
queue
Syntax queue queue-id [port-redirect-group-queue]
no queue queue-id
Context config>qos>sap-egress>hsmda-queues
Description This command, within the QoS policy HSMDA-queues context, is a container for the configuration parame-
ters controlling the behavior of an HSMDA queue. Unlike the standard QoS policy queue command, this
command is not used to actually create or dynamically assign the queue to the object which the policy is
applied. The queue identified by queue-id always exists on the SAP or subscriber context whether the com-
mand is executed or not. In the case of HSMDA SAPs and subscribers, all eight queues exist at the moment
the sys- tem allocates an HSMDA queue group to the object (both ingress and egress).
Best-Effort, Expedited and Auto-Expedite Queue Behavior Based on Queue-ID
With standard service queues, the scheduling behavior relative to other queues is based on two items,
the queues Best-Effort or Expedited nature and the dynamic rate of the queue relative to the defined
CIR. HSMDA queues are handled differently. The create time auto-expedite and explicit expedite and
best-effort qualifiers have been eliminated and instead the scheduling behavior is based solely on the
queues identifier. Queues with a queue-id equal to 1 are placed in scheduling class 1. Queues with
queue-id 2 are placed in scheduling class 2. And so on up to scheduling class 8. Each scheduling class is
either mapped directly to a strict scheduling priority level based on the class ID, or the class may be
placed into a weighted scheduling class group providing byte fair weighted round robin scheduling
between the members of the group. Two weighted groups are supported and each may contain up to
three consecutive scheduling classes. The weighed group assumes its highest member class's inherent
strict scheduling level for scheduling purposes. Strict priority level 8 has the highest priority while strict
level 1 has the lowest. When grouping of scheduling classes is defined, some of the strict levels will not
be in use.
Single Type of HSMDA Queues
Another difference between HSMDA queues and standard service queues is the lack of Multipoint
queues. At ingress, an HSMDA SAP or subscriber does not require multi-point queues since all
forwarding types (broadcast, multicast, unicast and unknown) forward to a single destination, the
ingress forwarding plane on the IOM. Instead of a possible eight queues per forwarding type (for a total
of up to 32) within the SAP ingress QoS policy, the hsmda-queues node supports a maximum of eight
queues.
Every HSMDA Queue Supports Profile Mode Implicitly
Unlike standard service queues, the HSMDA queues do not need to be placed into the special mode
profile at create time in order to support ingress color aware policing. Each queue may handle in-
profile, out-of-profile and profile undefined packets simultaneously. As with standard queues, the
explicit profile of a packet is dependant on ingress sub-forwarding class to which the packet is mapped.

Queue sharing and redirection

7950 XRS Quality of Service Guide Page 225