Virtual Leased Line Services
7750 SR OS Services Guide Page 357
Description This command, within the QoS policy hsmda-queue context, is a container for the configuration
parameters 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 command is executed or not. In the case of HSMDA SAPs and subscribers, all
eight queues exist at the moment the system 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 classís 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 Multipoint queues since all
forwarding types (broadcast, multicast, unicast and unknown) forward to a single destination ñ 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.
The no form of the command restores the defined queue-id to its default parameters. All HSMDA
queues having the queue-id and associated with the QoS policy are re-initialized to default
parameters.
Parameters queue-id —
Specifies the HSMDA queue to use for packets in this forwarding class. This mapping is
used when the SAP is on a HSMDA MDA.
Values 1 — 8
rate
Syntax rate pir-rate [cir cir-rate]
no rate
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