Configuring Egress Queue Characteristics; Configuration Guidelines; Allocating Buffer Space To And Setting Wtd Thresholds For An Egress Queue-Set - Cisco IE-3000-8TC Software Configuration Manual

Chapter 36 Configuring QoS
This example shows how to assign the ingress bandwidths to the queues. Queue 1 is the priority queue
with 10 percent of the bandwidth allocated to it. The bandwidth ratios allocated to queues 1 and 2 is
4/(4+4). SRR services queue 1 (the priority queue) first for its configured 10 percent bandwidth. Then
SRR equally shares the remaining 90 percent of the bandwidth between queues 1 and 2 by allocating 45
percent to each queue:
Switch(config)# mls qos srr-queue input priority-queue 1 bandwidth 10
Switch(config)# mls qos srr-queue input bandwidth 4 4

Configuring Egress Queue Characteristics

Depending on the complexity of your network and your QoS solution, you might need to perform all of
the tasks in the next sections. You will need to make decisions about these characteristics:
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These sections contain this configuration information:
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Configuration Guidelines

Follow these guidelines when the expedite queue is enabled or the egress queues are serviced based on
their SRR weights:
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Allocating Buffer Space to and Setting WTD Thresholds for an Egress Queue-Set

You can guarantee the availability of buffers, set WTD thresholds, and configure the maximum
allocation for a queue-set by using the mls qos queue-set output qset-id threshold queue-id
drop-threshold1 drop-threshold2 reserved-threshold maximum-threshold global configuration commands.
OL-13018-03
Which packets are mapped by DSCP or CoS value to each queue and threshold ID?
What drop percentage thresholds apply to the queue-set (four egress queues per port), and how much
reserved and maximum memory is needed for the traffic type?
How much of the fixed buffer space is allocated to the queue-set?
Does the bandwidth of the port need to be rate limited?
How often should the egress queues be serviced and which technique (shaped, shared, or both)
should be used?
Configuration Guidelines, page 36-61
Allocating Buffer Space to and Setting WTD Thresholds for an Egress Queue-Set, page 36-61
(optional)
Mapping DSCP or CoS Values to an Egress Queue and to a Threshold ID, page 36-64
Configuring SRR Shaped Weights on Egress Queues, page 36-65
Configuring SRR Shared Weights on Egress Queues, page 36-66
Configuring the Egress Expedite Queue, page 36-67
Limiting the Bandwidth on an Egress Interface, page 36-67
If the egress expedite queue is enabled, it overrides the SRR shaped and shared weights for queue 1.
If the egress expedite queue is disabled and the SRR shaped and shared weights are configured, the
shaped mode overrides the shared mode for queue 1, and SRR services this queue in shaped mode.
If the egress expedite queue is disabled and the SRR shaped weights are not configured, SRR
services this queue in shared mode.
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Cisco IE 3000 Switch Software Configuration Guide
Configuring Standard QoS
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36-61