Enabling Dscp Transparency Mode - Cisco IE 3000 Software Configuration Manual

Chapter 32 Configuring QoS
trusted boundary feature disables the trusted setting on the switch port and prevents misuse of a
high-priority queue. Note that the trusted boundary feature is not effective if the PC and Cisco IP Phone
are connected to a hub that is connected to the switch.
In some situations, you can prevent a PC connected to the Cisco IP Phone from taking advantage of a
high-priority data queue. You can use the switchport priority extend cos interface configuration
command to configure the telephone through the switch CLI to override the priority of the traffic
received from the PC.
Beginning in privileged EXEC mode, follow these steps to enable trusted boundary on a port:
Command
Step 1 configure terminal
Step 2 cdp run
Step 3 interface interface-id
Step 4
cdp enable
Step 5
mls qos trust cos
mls qos trust dscp
Step 6 mls qos trust device cisco-phone
Step 7 end
Step 8 show mls qos interface
Step 9 copy running-config startup-config
To disable the trusted boundary feature, use the no mls qos trust device interface configuration
command.

Enabling DSCP Transparency Mode

The switch supports the DSCP transparency feature. It affects only the DSCP field of a packet at egress.
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.
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 packet.
OL-13018-01
Purpose
Enter global configuration mode.
Enable CDP globally. By default, CDP is enabled.
Specify the port connected to the Cisco IP Phone, and enter interface
configuration mode.
Valid interfaces include physical ports.
Enable CDP on the port. By default, CDP is enabled.
Configure the switch port to trust the CoS value in traffic received from the
Cisco IP Phone.
or
Configure the routed port to trust the DSCP value in traffic received from
the Cisco IP Phone.
By default, the port is not
ed.
Specify 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.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Cisco IE 3000 Switch Software Configuration Guide
Configuring Standard QoS
32-35