1-7
Table 1-4
How a packet is handled when the voice VLAN is operating in different modes
Voice VLAN
Mode
Packet Type
Processing Method
Untagged packet
Packet carrying the voice
VLAN tag
If the source MAC address of the packet
matches the OUI list, the packet is transmitted in
the voice VLAN. Otherwise, the packet is
dropped.
Security
Packet carrying any other
VLAN tag
The packet is forwarded or dropped based on
whether the receiving port is assigned to the
carried VLAN. The processing method is
irrelevant to the voice VLAN mode (security or
normal).
Untagged packet
Packet carrying the voice
VLAN tag
The source MAC address of the packet is not
checked. All such packets can be transmitted in
the voice VLAN.
Normal
Packet carrying any other
VLAN tag
The packet is forwarded or dropped based on
whether the port is assigned to the carried VLAN.
The processing method is irrelevant to the voice
VLAN mode (security or normal).
Voice VLAN Configuration
Configuration Prerequisites
z
Create the corresponding VLAN before configuring a voice VLAN.
z
VLAN 1 (the default VLAN) cannot be configured as a voice VLAN.
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.
But the Switch 4210 52-Port not to
modify the CoS and DSCP values
marked for incoming traffic of the
voice VLAN.
The
voice vlan qos
command