H3C Technologies H3C S12500 Series Switches - Manual (Page 50)

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Voice VLAN
mode
Packet type Packet processing mode
Normal mode
Untagged packets
The port does not check the source MAC addresses of inbound
packets. In this way, both voice traffic and non-voice traffic
can be transmitted in the voice VLAN.
Packets carrying the
voice VLAN tag
Packets carrying other
tags Forwarded or dropped depending on whether the port allows
packets of these VLANs to pass through
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 more
information, see " Configuring QoS priority settings for voice traffic on an interface ."
3. Configure the voice VLAN assignment mode.
For more information, see "
Configuring a port to operate in automatic voice VLAN assignment
mode " and " Configuring a port to operate in manual voice VLAN assignment mode ."
Configuration guidelines
• When EB or EC2 cards are operating in standard ACL mode, the ports on the EB or EC2 cards do
not support voice VLAN. For more information about the standard ACL mode, see ACL and QoS
Configuration Guide.
• A port can belong to only one voice VLAN at a time.
• Voice VLAN cannot be enabled on member ports of an aggregation group. For more information
about link aggregation member ports, see "Configuring Ethernet link aggregation."
Configuring QoS priority settings for voice traffic on
an interface
IMPORTANT:
Configure the QoS priority settings for voice traffic on an interface before enabling voice VLAN on the
interface. If the configuration order is reversed, your priority trust setting will fail.
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 switch
either to modify or not to modify the QoS priority settings carried by incoming voice traffic.