Standard Qos Configuration Guidelines - Cisco Catalyst 3750-E Software Configuration Manual

Chapter 37 Configuring QoS
Default Mapping Table Configuration
Table 37-12 on page 37-74
Table 37-13 on page 37-75
Table 37-14 on page 37-77
The default DSCP-to-DSCP-mutation map is a null map, which maps an incoming DSCP value to the
same DSCP value.
The default policed-DSCP map is a null map, which maps an incoming DSCP value to the same DSCP
value (no markdown).

Standard QoS Configuration Guidelines

Before beginning the QoS configuration, you should be aware of this information in these sections:
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QoS ACL Guidelines
These are the guidelines with for configuring QoS with access control lists (ACLs):
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IPv6 QoS ACL Guidelines
See
Applying QoS on Interfaces
These are the guidelines for configuring QoS on physical ports and SVIs (Layer 3 VLAN interfaces):
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OL-9775-08
shows the default CoS-to-DSCP map.
shows the default IP-precedence-to-DSCP map.
shows the default DSCP-to-CoS map.
"QoS ACL Guidelines" section on page 37-39
"IPv6 QoS ACL Guidelines" section on page 37-39
"Applying QoS on Interfaces" section on page 37-39
"Configuring IPv6 QoS on Switch Stacks" section on page 37-40
"Policing Guidelines" section on page 37-40
"General QoS Guidelines" section on page 37-41
It is not possible to match IP fragments against configured IP extended ACLs to enforce QoS. IP
fragments are sent as best-effort. IP fragments are denoted by fields in the IP header.
Only one ACL per class map and only one match class-map configuration command per class map
are supported. The ACL can have multiple ACEs, which match fields against the contents of the
packet.
A trust statement in a policy map requires multiple hardware entries per ACL line. If an input service
policy map contains a trust statement in an ACL, the access list might be too large to fit into the
available QoS hardware memory, and an error can occur when you apply the policy map to a port.
Whenever possible, you should minimize the number of lines is a QoS ACL.
Understanding IPv6 ACLs, page
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.
36-1.
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
Configuring Standard QoS
37-39