Automatic QoS 327
Automatic QoS
Auto-QoS facilitates the QoS configuration process for the Catalyst 6500. At the time of
writing, Auto-QoS is available with CatOS Software Release 7.5. Auto-QoS assists the
administrator in configuring classification, congestion management, mapping, and
congestion avoidance. The Auto-QoS feature on the Catalyst 6500 is divided into two
components. Global Auto-QoS provides recommended QoS parameters on a switch-wide
basis, whereas port-specific Auto-QoS configures parameters on a per-interface basis. With
CatOS Release 7.5, Auto-QoS commands are specifically focused on voice-related appli-
cations. However, future software releases will provide additional functionality and
capabilities.
NOTE At the time of writing, Auto-QoS is not available in Cisco IOS for the Catalyst 6500.
However, there are plans to integrate the feature in future Cisco IOS releases.
Global Auto-QoS
The global Auto-QoS command focuses on QoS parameters affecting the entire switch. To
enable global Auto-QoS, enter the following command in enable mode on the supervisor:
ss
ss
ee
ee
tt
tt
qq
qq
oo
oo
ss
ss
aa
aa
uu
uu
tt
tt
oo
oo
qq
qq
oo
oo
ss
ss
When you enter the preceding command, any QoS commands previously configured are
modified. Therefore, you should enable any Auto-QoS commands prior to manually
Example 8-44 Configuring WRED Transmit Queue Thresholds in Native Mode
native(config-if)# wrr-queue random-detect min-threshold 1 75
WRED_threshold configured on all 48 ports on slot 3.
native(config-if)# wrr-queue random-detect min-threshold 2 75
WRED_threshold configured on all 48 ports on slot 3.
native(config-if)# wrr-queue random-detect min-threshold 3 80
WRED_threshold configured on all 48 ports on slot 3.
native# show queueing interface fastEthernet 3/1
Interface FastEthernet3/1 queueing strategy: Weighted Round-Robin
Port QoS is enabled
Trust state: trust IP Precedence
Default COS is 0
Transmit queues [type = 1p3q1t]:
(text omitted)
queue random-detect-min-thresholds
----------------------------------
1 75[1]
2 75[1]
3 80[1]
328 Chapter 8: QoS Support on the Catalyst 6500
altering the switch QoS properties. set qos autoqos first enables QoS on the switch, if it is
not already enabled. The global Auto-QoS command does not alter any default QoS config-
urations applied at the port level. Because congestion management, congestion avoidance,
and CoS-to-queue mappings depend on port types rather than specific ports, commands
related to these mechanisms are incorporated into the global Auto-QoS command. Refer to
Table 8-2 for a detailed list of the various modules and the corresponding port types, and
review the section “Catalyst Feature Overview” in Chapter 3, which provides additional
information on port type nomenclature. Tables 8-21 and 8-22 list the resulting commands
executed when configuring global Auto-QoS.
*Command is enabled on the switch if it was not previously enabled.
**All normal and excess rate policed DSCP map values are configured for default values. The exception is DSCP
26 and DSCP 46.
Table 8-21 Added Global Auto-QoS Configuration Commands
* set qos enable
set qos policy-source local
set qos acl default-action ip dscp 0
set qos ipprec-dscp-map 0 10 18 24 34 46 48 56
set qos cos-dscp-map 0 10 18 24 34 46 48 56
set qos dscp-cos-map 0-7:0 8-15:1 16-23:2 24-31:3 32-39:4 40-47:5 48-55:6 56-63:7
** set qos policed-dscp-map 26:0
** set qos policed-dscp-map 46:0
Table 8-22 Added Global Auto-QoS Port Type Configuration Commands
2q2t/1q4t
set qos map 2q2t tx queue 2 2 cos 5,6,7
set qos map 2q2t tx queue 2 1 cos 1,2,3,4
set qos map 2q2t tx queue 1 1 cos 0
set qos drop-threshold 2q2t tx queue 1 100 100
set qos drop-threshold 2q2t tx queue 2 80 100
set qos drop-threshold 1q4t rx queue 1 50 60 80 100
set qos txq-ratio 2q2t 80 20
set qos wrr 2q2t 100 255
1p3q1t/1p1q0t
set qos map 1p3q1t tx 1 1 cos 0
set qos map 1p3q1t tx 2 1 cos 1,2
set qos map 1p3q1t tx 3 1 cos 3,4

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