Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 44 Configuring Quality of Service
Configuring VSS QoS
Classification
The supervisor engine supports classification of Layer 2, IP, IPv6 packets, and ARP packets marking
performed on input can be matched in the output direction. The previous table lists the full set of
capabilities. By default, the switch also supports classification resources sharing. Similarly, when the
same policy is attached to a port or a VLAN or on per-port per-vlan targets, ACL entries are shared
though QoS actions are unique on each target.
For example:
class-map c1
match ip dscp 50
Policy Map p1
class c1
police rate 1 m burst 200000
If policy-map p1 is applied to interfaces Gig 1/1 and Gig 1/2, 1 CAM entry is used (one ACE that
matches IP packets), but 2 policers are allocated (one per target). So, all IP packets with dscp 50 are
policed to 1 mbps on interface Gig 1/1 and packets on interface Gig 1/2 are policed to 1 mbps.
Note With Cisco IOS Release 12.2(46)SG, you can issue the match protocol arp command. For details, see
the Catalyst 4500 Series Switch Cisco IOS Command Reference .
Classification Statistics
The supervisor engine supports only packet based classification statistics and TCAM resource sharing.
When a policy-map is applied on multiple targets, the command
show policy-map interface displays
the aggregate classification statistics, not those specific to an interface.
Note
To obtain per interface policy-map stats, you should configure a unique policy-map name on each
interface.
When a policy-map is attached to a port-channel member ports, classification statistics are not displayed.
Configuring a Policy Map
You can attach only one policy map to an interface. Policy maps can contain one or more policy-map
classes, each with different match criteria and actions.
Configure a separate policy-map class in the policy map for each type of traffic that an interface receives.
Put all commands for each type of traffic in the same policy-map class. QoS does not attempt to apply
commands from more than one policy-map class to matched traffic.
Creating a Policy Map
To create a policy map, enter this command:
Command Purpose
Switch(config)# [ no ] policy-map policy_name
Creates a policy map with a user-specified name.
Use the no keyword to delete the policy map.