27-52
Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 27 Configuring QoS
Configuring QoS
This example shows a policy map with a specified bandwidth and queue size. Traffic that is not DSCP 30
or 10 is assigned a queue-limit of 2000 bytes. Traffic with a DSCP value of 30 is assigned a queue-limit
of 1000 bytes, and traffic with a DSCP value of 10 is assigned a queue-limit of 1500 bytes. All traffic
not belonging to the class traffic is classified into class-default, which is configured with 10 percent of
the total available bandwidth and a large queue size of 3000 bytes.
Switch(config)#
policy-map gold-policy
Switch(config-pmap)#
class traffic
Switch(config-pmap-c)#
bandwidth percent 50
Switch(config-pmap-c)#
queue-limit bytes 2000
Switch(config-pmap-c)#
queue-limit dscp 30 bytes 1000
Switch(config-pmap-c)#
queue-limit dscp 10 bytes 1500
Switch(config-pmap-c)#
exit
Switch(config-pmap)#
exit
Switch(config-pmap)#
class class-default
Switch(config-pmap-c)#
bandwidth percent 10
Switch(config-pmap-c)#
queue-limit bytes 3000
Switch(config-pmap-c)#
exit
Switch(config-pmap)#
exit
Switch(config)#
interface gigabitethernet0/1
Switch(config-if)#
service-policy output gold-policy
Switch(config-if)#
exit
There can be only three unique qualified queue-limit thresholds. In this example, there are four unique
thresholds, so the configuration is rejected:
Switch(config-pmap-c)#
queue-limit 100 us
Switch(config-pmap-c)#
queue-limit cos 2 200 us
Switch(config-pmap-c)#
queue-limit cos 3 300 us
Switch(config-pmap-c)#
queue-limit cos 4 400 us
In the next example, although there appear to be only three unique thresholds, in reality there are four
threshold configurations, including an implied default threshold. The configuration is rejected.
Switch(config-pmap-c)#
queue-limit cos 2 200 us
Switch(config-pmap-c)#
queue-limit cos 3 300 us
Switch(config-pmap-c)#
queue-limit cos 4 400 us
In this last example, there are only three unique thresholds and the configuration is allowed.
Switch(config-pmap-c)#
queue-limit 100 us
Switch(config-pmap-c)#
queue-limit cos 2 100 us
Switch(config-pmap-c)#
queue-limit cos 3 300 us
Switch(config-pmap-c)#
queue-limit cos 4 400 us
Hierarchical Policy Maps Configuration Examples
These are examples of using policy maps to configure hierarchical QoS.
Configure policy maps phb and vlan:
Switch(config)#
policy-map phb
Switch(config-pmap)#
class cos1
Switch(config-pmap-c)#
shape average 1000
Switch(config-pmap-c)#
exit
Switch(config-pmap)#
class cos2
Switch(config-pmap-c)#
shape average 2000
Switch(config-pmap-c)#
exit
Switch(config-pmap)#
exit
Switch(config)#
policy-map vlan
Switch(config-pmap)#
class vlan1
Switch(config-pmap-c)#
shape average 5000
