Enterprise QoS Solution Reference Network Design Guide

Chapter 2 Campus QoS Design
show mls qos maps cos-output-q
Version 3.3
Catalyst 2970/3560/3750—QoS Considerations and Design
In the example below, each queue has a default buffer allocation of 25%. Additionally, all WTD
Thresholds are set to 100% (the tail of the queue), except for Queue 2 Threshold 1 (set to 70%), Queue
2 Threshold 2 (set to 80%), and Queue 4 Threshold 1 (set to 40%).
Example 2-33 Show MLS QoS Queue-Set Verification for a Catalyst 2970/3560/3750 Switch
CAT2970#show mls qos queue-set 1
Queueset: 1
Queue : 1 2 3 4
---------------------------------------------buffers
: 25 25 25 25
threshold1: 100 70 100 40
threshold2: 100 80 100 100
reserved : 50 100 50 100
maximum : 400 100 400 100
CAT2970#
The show mls qos maps cos-output-q verification command truncates the show mls qos maps output
to only report the CoS-to-Queue/Threshold mappings for egress queues.
In the example below, CoS 0 is mapped to Q3T3, CoS 1 is mapped to Q4T3, CoS 2 is mapped to Q2T1,
CoS 3 is mapped to Q2T2, CoS 4 is mapped to Q2T1, CoS 5 is mapped to Q1T3 (the PQ), and CoS 6
and CoS 7 are mapped to Q2T3.
Example 2-34 Show MLS QoS Maps CoS-Output-Q Verification for a Catalyst 2970/3560/3750 Switch
CAT2970#show mls qos maps cos-output-q
Cos-outputq-threshold map:
cos: 0 1 2 3 4 5 6 7
-----------------------------------queue-threshold:
3-3 4-3 2-1 2-2 2-1 1-3 2-3 2-3
CAT2970#
show mls qos maps dscp-output-q
The show mls qos maps dscp-output-q verification command truncates the show mls qos maps output
to only report the DSCP-to-Queue/Threshold mappings for egress queues. The output is shown in tabular
form, with the first digit of the decimal DSCP value in rows and the second digit in columns.
In the example below, only standard DSCP PHBs are being mapped away from the default settings (with
the exception of the temporary marking of DSCP 25 for Mission-Critical Data). The other non-standard
values may be mapped to reflect the CoS-to-Queue mappings, but for example simplicity this has not
been done in this case.
Specifically, DSCP 0 is mapped to Q3T3; DSCP CS1 (8) is mapped to Q4T1; DSCP AF11, AF12, and
AF13 (10, 12, 14) are mapped to Q4T3; DSCP CS2 (16) is mapped to Q2T1 as are DSCP AF21, AF22,
and AF23 (18, 20, 22); DSCP CS3 (24) and AF31 (26) are mapped to Q2T2; DSCP CS4 (32) is mapped
to Q2T1 as are DSCP AF41, AF42, and AF43 (34, 36, 38); DSCP EF (46) is mapped to Q1T3 (the PQ);
DSCP CS6 (48) and CS7 (56) are mapped to Q2T3. The non-standard DSCP 25 is mapped to Q2T1.
Example 2-35 Show MLS QoS Maps DSCP-Output-Q Verification for a Catalyst 2970/3560/3750
Switch
CAT2970#show mls qos maps dscp-output-q
Enterprise QoS Solution Reference Network Design Guide
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