H3C Technologies H3C S7500E Series Switches - Manual (Page 252)

18-6
Configuring a Voice VLAN
Configuration Prerequisites
1) Create a VLAN
Before configuring a VLAN as a voice VLAN, create the VLAN first.
2) Configure QoS priority settings for voice traffic on an interface
Configure QoS priority settings for voice VLAN traffic on an interface before enabling voice VLAN on
the interface. If the configuration order is reversed, your priority configuration will fail. For details, see
Configuring QoS Priority Settings for Voice Traffic on an Interface .
3) Configure the voice VLAN assignment mode. For details, see Setting a Port to Operate in
Automatic Voice VLAN Assignment Mode and Setting a Port to Operate in Manual Voice VLAN
Assignment Mode.
A port can belong to only one voice VLAN at a time.
Voice VLAN cannot be enabled on a port with Link Aggregation Control Protocol (LACP) enabled.
Configuring QoS Priority Settings for Voice Traffic on an Interface
In voice VLAN applications, you can improve the quality of voice traffic by configuring the appropriate
QoS priority settings, including the Class of Service (CoS) and Differentiated Services Code Point
(DSCP) values, for voice traffic. Voice traffic carries its own QoS priority settings. You can configure the
device either to modify or not to modify the QoS priority settings carried by incoming voice traffic.
Follow these steps to configure QoS priority settings for voice traffic:
To do... Use the command... Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Configure the interface to trust the
QoS priority settings in incoming
voice traffic, that is, not to modify
the CoS and DSCP values marked
for incoming traffic of the voice
VLAN
voice vlan qos trust
Configure the interface to modify
the CoS and DSCP values marked
for incoming traffic of the voice
VLAN into specified values
voice vlan qos cos-value
dscp-value
Required
Use either command
By default, an interface modifies the
CoS value and the DSCP value
marked for voice VLAN traffic into 6
and 46 respectively.
The voice vlan qos command and
the voice vlan qos trust command
can overwrite each other, whichever
is configured last.