38-34
Cisco IE 2000 Switch Software Configuration Guide
OL-25866-01
Chapter 38 Configuring Standard QoS
How to Configure Standard QoS
Configuring a Trusted Boundary to Ensure Port SecurityEnabling DSCP Transparency Mode
To configure the switch to modify the DSCP value based on the trust setting or on an ACL by disabling
DSCP transparency, use the mls qos rewrite ip dscp global configuration command.
Step 3 mls qos cos {default-cos | override}Configures the default CoS value for the port.
default-cos—Specifies a default CoS value to be assigned to a port. If
the packet is untagged, the default CoS value becomes the packet CoS
value. The CoS range is 0 to 7. The default is 0.
override—Overrides the previously configured trust state of the
incoming packet and applies the default port CoS value to the port on
all incoming packets. By default, CoS override is disabled.
Use the override keyword when all incoming packets on specified ports
deserve higher or lower priority than packets entering from other ports.
Even if a port was previously set to trust DSCP, CoS, or IP precedence,
this command overrides the previously configured trust state, and all
the incoming CoS values are assigned the default CoS value configured
with this command. If an incoming packet is tagged, the CoS value of
the packet is modified with the default CoS of the port at the ingress
port.
Step 4 end Returns to privileged EXEC mode.
Command Purpose
Step 1 configure terminal Enters global configuration mode.
Step 2 cdp run Enables CDP globally. By default, CDP is enabled.
Step 3 interface interface-id Specifies the port connected to the Cisco IP phone, and enters interface
configuration mode.
Valid interfaces include physical ports.
Step 4 cdp enable Enables CDP on the port. By default, CDP is enabled.
Step 5 mls qos trust cos
mls qos trust dscp
Configures the switch port to trust the CoS value in traffic received from the
Cisco IP phone.
or
Configures the routed port to trust the DSCP value in traffic received from
the Cisco IP phone.
By default, the port is not trusted.
Step 6 mls qos trust device cisco-phone Specifies that the Cisco IP phone is a trusted device.
You cannot enable both trusted boundary and auto-QoS (auto qos voip
interface configuration command) at the same time; they are mutually
exclusive.
Step 7 end Returns to privileged EXEC mode.
Command Purpose