In Cumulus Linux, a voice VLAN is a VLAN dedicated to voice traffic on a switch port. However, the term can mean different things to different vendors.
Voice VLAN is part of a trunk port with 2 VLANs that comprises either:
- Native VLAN, which carries both data and voice traffic, or
- Voice VLAN, which carries the voice traffic, and a data or native VLAN, which carries the data traffic in a trunk port.
The voice traffic is an 802.1q-tagged packet with a VLAN ID that has a VLAN ID (which may or may not be 0) and an 802.1p (3-bit layer 2 COS) with a specific value (typically 5 is assigned for voice traffic).
Data traffic is always untagged.
Cumulus Linux Voice VLAN Example
You can configure the topology above using the following NCLU commands. In this configuration:
- swp1 data traffic traverses the bridge's native VLAN and the voice traffic traverses VLAN 200
- swp2 data traffic traverses VLAN 10 and the voice traffic traverses VLAN 100
- swp3 data and voice traffic both traverse the bridge's native VLAN
These commands create the following configuration snippet in the
Configuring voice VLAN with NCLU does not configure
lldpd in Cumulus Linux, so LLDP-MED does not provide data and voice VLAN information. You can configure LLDP-MED for each interface in a new file in
/etc/lldp.d. In the following example, the file is called
You can also use the
lldpcli command to configure an LLDP-MED network policy. However,
lldpcli commands do not persist across reboots of the switch.
bridge-vids can be reviewed with the
net show bridge vlan command:
You can get MAC address information using the
net show bridge macs command:
You can capture LLDP information by checking
syslog or using
tcpdump on an interface.
Caveats and Errata
- A static voice VLAN configuration overwrites a switch port's existing configuration.
- Removing the
bridge-pvidconfiguration from a voice VLAN does not remove the VLAN from the bridge.