topic Re: voice vlan enabled on interface and behavior in Switching

voice vlan enabled on interface and behavior

romanroma — Wed, 18 Aug 2021 13:54:47 GMT

One of my clients is rolling out VoIP, so I wanted to use the 'voice vlan'.

interface GigabitEthernet1/0/13
 switchport access vlan 1001
 switchport mode access
 switchport voice vlan 200
end

When I plug a Polycom phone it the interface, LLDP does its magic and the phone appears to be on vlan 200. I can verify this by showing the CAM table; however, the phone's MAC address also shows up on vlan 1001. In addition, the interface does not appear to be in a trunk state, which I thought would happen so the proper vlan tag would get applied. When I link a computer downstream from phone, the computer's MAC shows up in 'vlan1001', so everything appears to be working.

However, I was just worried if I should be seeing this interface negotiate and form a 802.1Q port. I am also worried I see the phone's MAC on both vlans.

Switch in question is a 2960x.

Re: voice vlan enabled on interface and behavior

Elliot Dierksen — Wed, 18 Aug 2021 13:57:17 GMT

That is normal behavior. The phone sends CDP/LLDP packets in the untagged VLAN, so that is why the switch has learned that MAC address in the untagged VLAN. Once the device learns the voice vlan, the rest of its traffic should be in that tagged VLAN.

Re: voice vlan enabled on interface and behavior

balaji.bandi — Wed, 18 Aug 2021 14:02:33 GMT

can you post example :

if i look at the port mac address they show different vlan with respective vlan mac address example :

#show mac address-table interface fastEthernet 3/0/21
Mac Address Table
-------------------------------------------

Vlan Mac Address Type Ports
---- ----------- -------- -----
3 001e.caed.XXXX STATIC Fa3/0/21 <-- voice vlan
30 9457.a5ed.XXXX STATIC Fa3/0/21 <<-- data vlan
Total Mac Addresses for this criterion: 2

Re: voice vlan enabled on interface and behavior

romanroma — Wed, 18 Aug 2021 14:09:18 GMT

@balaji.bandi

HI,

I am not on site today for that client, but it looks like this if I remember correctly.

#show mac address-table interface fastEthernet 3/0/21
Mac Address Table
-------------------------------------------

Vlan Mac Address Type Ports
---- ----------- -------- -----
3 001e.caed.XXXX STATIC Fa3/0/21 <-- voice vlan
30 001e.caed.XXXX STATIC Fa3/0/21
30 9457.a5ed.XXXX STATIC Fa3/0/21 <<-- data vlan
Total Mac Addresses for this criterion: 2

Re: voice vlan enabled on interface and behavior

balaji.bandi — Wed, 18 Aug 2021 14:35:41 GMT

post the correct output, so we can look.