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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 33 Configuring QoS
Understanding QoS
parent-level class map.You can configure multiple service classes at the parent level to match different
combinations of VLANs, and you can apply independent QoS policies to each parent service class using
any child policy map.
Note A per-port, per-VLAN parent-level class map supports only a child-policy association; it does not allow
any actions to be configured. In addition, for a parent-level class map, you cannot configure an action or
a child-policy association for the class class-default.
Per-port, per-VLAN QoS has these limitations:
• You can apply a per-port, per-VLAN hierarchical policy map only to trunk ports.
• You can configure classification based on VLAN ID only in the parent le vel of a per-port, per -VLAN
hierarchical policy map.
• When the child policy map attached to a VLAN or set of VLANs contains only Layer 3 classification
(match ip dscp, match ip precedence, match IP ACL), you must be careful to ensure that these
VLANs are not carried on any port other than the one on which this per-port, per-VLAN policy is
attached. Not following this restriction could result in improper QoS behavior for traffic ingressing
the switch on these VLANs.
• We also recommend that you restrict VLAN membership on the trunk ports to which the per-port,
per-VLAN is applied by using the switchport trunk allowed vlan interface configuration
command. Overlapping VLAN membership between trunk ports that have per-port, per-VLAN
policies with Layer 3 classification could also result in unexpected QoS behavior.
In this example, the class maps in the child-level policy map specify matching criteria for voice, data,
and video traffic, and the child policy map sets the action for input policing each type of traffic. The
parent-level policy map specifies the VLANs to which the child policy maps are applied on the specified
port.
Switch(config)# class-map match-any dscp-1 data
Switch(config-cmap)# match ip dscp 1
Switch(config-cmap)# exit
Switch(config)# class-map match-any dscp-23 video
Switch(config-cmap)# match ip dscp 23
Switch(config-cmap)# exit
Switch(config)# class-map match-any dscp-63 voice
Switch(config-cmap)# match ip dscp-63
Switch(config-cmap)# exit
Switch(config)# class-map match-any customer-1-vlan
Switch(config-cmap)# match vlan 100
Switch(config-cmap)# match vlan 200
Switch(config-cmap)# match vlan 300
Switch(config-cmap)# exit
Note You can also enter the match criteria as match vlan 100 200 300 with the same result.
Switch(config)# policy-map child policy-1
Switch(config-pmap)# class dscp-63 voice
Switch(config-pmap-c)# police cir 10000000 bc 50000
Switch(config-pmap-c)# conform-action set-cos-transmit 5
Switch(config-pmap-c)# exceed-action drop
Switch(config-pmap-c)# exit
Switch(config-pmap)# class dscp-1 data
Switch(config-pmap-c)# set cos 0
Switch(config-pmap-c)# exit
Switch(config-pmap)# class dscp-23 video
Switch(config-pmap-c)# set cos 4