Mls Qos Rewrite Ip Dscp - Cisco Catalyst 3120 Command Reference Manual

Catalyst blade switch 3120 for hp command reference

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Cisco Catalyst Blade Switch 3120 for HP Cisco IOS Commands

mls qos rewrite ip dscp

Use the mls qos rewrite ip dscp global configuration command on the switch stack or on a standalone

switch to configure the switch to change (rewrite) the Differentiated Services Code Point (DSCP) field

of an incoming IP packet. Use the no form of this command to configure the switch to not modify

(rewrite) the DSCP field of the packet and to enable DSCP transparency.

Syntax Description

This command has no arguments or keywords.

DSCP transparency is disabled. The switch changes the DSCP field of the incoming IP packet.

Command Modes

Global configuration

Command History

Usage Guidelines

DSCP transparency affects only the DSCP field of a packet at the egress. If DSCP transparency is

enabled by using the no mls qos rewrite ip dscp command, the switch does not modify the DSCP field

in the incoming packet, and the DSCP field in the outgoing packet is the same as that in the incoming

Enabling DSCP transparency does not affect the port trust settings on IEEE 802.1Q tunneling ports.

By default, DSCP transparency is disabled. The switch modifies the DSCP field in an incoming packet,

and the DSCP field in the outgoing packet is based on the quality of service (QoS) configuration,

including the port trust setting, policing and marking, and the DSCP-to-DSCP mutation map.

Regardless of the DSCP transparency configuration, the switch modifies the internal DSCP value of the

packet that the switch uses to generate a class of service (CoS) value representing the priority of the

traffic. The switch also uses the internal DSCP value to select an egress queue and threshold.

For example, if QoS is enabled and an incoming packet has a DSCP value of 32, the switch might modify

the internal DSCP value based on the policy-map configuration and change the internal DSCP value

to 16. If DSCP transparency is enabled, the outgoing DSCP value is 32 (same as the incoming value). If

DSCP transparency is disabled, the outgoing DSCP value is 16 because it is based on the internal DSCP

mls qos rewrite ip dscp

no mls qos rewrite ip dscp

Modification

This command was introduced.

Cisco Catalyst Blade Switch 3120 for HP Command Reference

mls qos rewrite ip dscp