The term "Voice VLAN" can be confusing, as it means different things to different vendors. In Cumulus Linux, a Voice VLAN is a VLAN dedicated to Voice traffic on a switch.
On Cisco Systems' Catalyst software, when a switch port is configured as an access port (switchport mode access), and has a Voice VLAN configured on that switch port, the switch port behaves identically to a 802.1q trunk. This means that the untagged VLAN is configured for the personal computer (PC), and the tagged VLAN is configured for the Voice over IP (VoIP) handset, effectively configuring the switch port as a trunk with 2 VLANs (one tagged and one un-tagged).
Environment
- Cumulus Linux 3.0.0 - 3.4.3
Cumulus Linux Voice VLAN Example
The topology above is shown in the /etc/network/interfaces
file as follows:
auto bridge iface bridge bridge-vlan-aware yes bridge-ports swp1 swp2 swp3 bridge-vids 1-1000 bridge-pvid 1 auto swp1 iface swp1 bridge-vids 200 bridge-pvid 100 mstpctl-bpduguard yes mstpctl-portadminedge yes auto swp2 iface swp2 bridge-vids 200 bridge-pvid 100 mstpctl-bpduguard yes mstpctl-portadminedge yes
The bridge-vids
can be reviewed with the Linux command "bridge
":
cumulus@ig-spine-01:mgmt-vrf:~$ bridge -c vlan show port vlan ids swp1 100 PVID Egress Untagged 200 swp2 100 PVID Egress Untagged 200 swp3 1 PVID Egress Untagged 2-1000
Cumulus Linux vs Cisco IOS Configuration
Cumulus Linux /etc/network/interfaces |
Cisco IOS |
auto swp1 iface swp1 bridge-vids 200 bridge-pvid 100 mstpctl-bpduguard yes mstpctl-portadminedge yes |
interface FastEthernet0/1 switchport access vlan 100 switchport voice vlan 200 spanning-tree portfast spanning-tree bpduguard enable |
Cisco Voice VLAN and 802.1q Trunk Differences
Behavior | Cumulus Linux Trunk | Cisco Voice VLAN |
CoS & 802.1p |
|
|
Portfast |
|
|
Trust CoS on Phone |
|
|
Automatic Detection |
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