CLI Reference Guide-R05

Chapter 19 | VLAN Commands
Configuring Voice VLANs
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Command Mode
Global Configuration
Command Usage
◆ When IP telephony is deployed in an enterprise network, it is recommended to
isolate the Voice over IP (VoIP) network traffic from other data traffic. Traffic
isolation helps prevent excessive packet delays, packet loss, and jitter, which
results in higher voice quality. This is best achieved by assigning all VoIP traffic
to a single VLAN.
◆ VoIP traffic can be detected on switch ports by using the source MAC address of
packets, or by using LLDP (IEEE 802.1AB) to discover connected VoIP devices.
When VoIP traffic is detected on a configured port, the switch automatically
assigns the port as a tagged member of the Voice VLAN.
◆ Only one Voice VLAN is supported and it must already be created on the switch
before it can be specified as the Voice VLAN.
◆ The Voice VLAN ID cannot be modified when the global auto-detection status
is enabled (see the switchport voice vlan command.
Example
The following example enables VoIP traffic detection and specifies the Voice VLAN
ID as 1234.
Console(config)#voice vlan 1234
Console(config)#
voice vlan aging This command sets the Voice VLAN ID time out. Use the no form to restore the
default.
Syntax
voice vlan aging minutes
no voice vlan
minutes - Specifies the port Voice VLAN membership time out.
(Range: 5-43200 minutes)
Default Setting
1440 minutes
Command Mode
Global Configuration
Command Usage
The Voice VLAN aging time is the time after which a port is removed from the Voice
VLAN when VoIP traffic is no longer received on the port.