Cisco Catalyst 2960 Series, Configuration Manual

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Configuring Ingress 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 modules. You need to make decisions about these characteristics:
• Which packets are assigned (by DSCP or CoS value) to each queue?
• What drop percentage thresholds apply to each queue, and which CoS or DSCP values map to each
threshold?
• How much of the available buffer space is allocated between the queues?
• How much of the available bandwidth is allocated between the queues?
• Is there traffic (such as voice) that should be given high priority?
Related Topics
Priority Queueing, on page 559
Ingress Port Activity
Configuration Guidelines
Follow these guidelines when the expedite queue is enabled or the egress queues are serviced based on their
SRR weights:
• 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.
Mapping DSCP or CoS Values to an Ingress Queue and Setting WTD Thresholds
You can prioritize traffic by placing packets with particular DSCPs or CoSs into certain queues and adjusting
the queue thresholds so that packets with lower priorities are dropped.
Beginning in privileged EXEC mode, follow these steps to map DSCP or CoS values to an ingress queue and
to set WTD thresholds. This procedure is optional.
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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How to Configure QoS