Qos Strict Priority Queuing (Spq) - Avaya 1000 Series Configuration Manual

3. Specify the burst-tolerance:

QOS Strict Priority Queuing (SPQ)

Secure Router supports Strict Priority Queuing (SPQ) to minimize latency and jitter for traffic
on Main Ethernet interfaces and MLPPP ,PPP, and HDLC bundle interfaces. SPQ uses the
shaping and scheduling infrastructure currently used with Class Based Queuing (CBQ), so
there is minimal change to QoS configuration. Traffic is classified and marked as before. When
SPQ is enabled, instead of queuing the classified traffic into class queues, the traffic flows
through one of the interface queues based on the configuration. SPQ supports up to eight
different queues per physical interface in which each queue has a separate priority. This means
that multiple flows can be queued into a single queue if their priority values are the same. SPQ
can be enabled or disabled at the interface level for outbound flows, just like CBQ. Only CBQ or
SPQ can be active on any interface, yet both can be active at the same time on different
interfaces. The SPQ queues are named 1 through 8 where queue 1 is the highest priority and
the lowest priority is 8. All unclassified flows are dropped unless a default class is configured
and mapped to the lowest priority queue (queue 8).
Unlike CBQ where the committed rate percentage and peak rate percentage are specified
globally in the class map, with SPQ the committed rate percentage is specified for each queue
at the interface level with the shape command. The peak rate percentage is 100% for all SPQ
interface queues. After the committed rate percentage for all the queues has been observed
the remaining bandwidth is serviced by priority.
By default, the committed rate for any SPQ interface queue is zero. The latency for traffic for
a SPQ queue can increase once it exceeds the committed rate percentage for that queue.
CLI QOS Commands
To configure SPQ, you must configure the traffic classes for each traffic flow under the interface
tree and assign an SPQ queue number for each class with the assign_queue command. When
SPQ is enabled on an interface, the committed rate (cr_percent) and peak rate (br_percent)
values defined for the class are ignored. For SPQ, the committed rate is specified using the
queue command under the QoS section of the interface tree.
All the clear and show commands are equivalent for SPQ as for CBQ.
Mapping a traffic class to an SPQ queue on Ethernet interface
1. To enter configuration mode, enter:
Avaya Secure Router 1000 Series Configuration Guide
interface bundle <wan>
fr
pvc <pvc>
burst-tolerance <15–200>
QOS Strict Priority Queuing (SPQ)
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