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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 39 Configuring QoS Configuring Standard QoS
Applying QoS on Interfaces
These are the guidelines for configuring QoS on physical ports and SVIs (Layer 3 VLAN interfaces):
• You can configure QoS on physical ports and SVIs. When configuring QoS on physical ports, you
create and apply nonhierarchical policy maps. When configuring QoS on SVIs, you can create and
apply nonhierarchical and hierarchical policy maps.
• Incoming traffic is classified, policed, and marked down (if configured) regardless of whether the
traffic is bridged, routed, or sent to the CPU. It is possible for bridged frames to be dropped or to
have their DSCP and CoS values modified.
• Follow these guidelines when configuring policy maps on physical ports or SVIs:
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You cannot apply the same policy map to a physical port and to an SVI.
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If VLAN-based QoS is configured on a physical port, the switch removes all the port-based
policy maps on the port. The traffic on this physical port is now affected by the policy map
attached to the SVI to which the physical port belongs.
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In a hierarchical policy map attached to an SVI, you can only configure an individual policer at
the interface level on a physical port to specify the bandwidth limits for the traffic on the port.
The ingress port must be configured as a trunk or as a static-access port. You cannot configure
policers at the VLAN level of the hierarchical policy map.
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The switch does not support aggregate policers in hierarchical policy maps.
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After the hierarchical policy map is attached to an SVI, the interface-level policy map cannot
be modified or removed from the hierarchical policy map. A new interface-level policy map also
cannot be added to the hierarchical policy map. If you want these changes to occur, the
hierarchical policy map must first be removed from the SVI. You also cannot add or remove a
class map specified in the hierarchical policy map.
Configuring IPv6 QoS on Switch Stacks
Note IPv6 QoS is not supported on switches running the LAN base feature set.
You can enable IPv6 QoS on a switch or a switch stack. If the stack includes only Catalyst 3750-X and
Catalyst 3750-E switches, the QoS configuration applies to all traffic. These are the guidelines for IPv6
QoS in a stack that includes one or more Catalyst 3750 switches:
• Any switch can be the stack master.
• You can attach policies with IPv6 ACLs only on Catalyst 3750-X and 3750-E switch interfaces.
• You can modify an attached policy to include an IPv6 ACL only on Catalyst 3750-X and
Catalyst 3750-E switch interfaces.
• A policy that includes the match protocol IPv6 classification applies only on Catalyst 3750-X and
Catalyst 3750-E switch interfaces.
• A QoS policy with both IPv4 and IPv6 classification can be attached to an SVI on a mixed switch
stack, but the policy applies to only IPv4 traffic entering Cisco 3750 switch interfaces, and to both
IPv4 and IPv6 traffic on Catalyst 3750-X and Catalyst 3750-E switch interfaces.
• IPv6 trust is supported on Catalyst 3750, Catalyst 3750-X, and Catalyst 3750-E switches.