Just spent a while going through previous posts and was very helpful to me in regards to how the Voice VLAN works.
Now one question
If the voice and data VLANs are setup and it uses a "special case" 802.1q trunk, can I assume that when packets are sent on either data or voice VLANs, they will have a full 802.1q header inserted between the Ethernet and IP headers and not some special or Cisco amended 802.1q header :
Ethernet II, Src: Cisco_ef:04:00 (00:03:e4:ef:04:00), Dst: Cisco_fe:d8:c0 (00:0a:f3:xx:xx:xx)
Type: 802.1Q Virtual LAN (0x8100)
802.1Q Virtual LAN
000. .... .... .... = Priority: 0
...0 .... .... .... = CFI: 0
.... 0000 1100 1010 = ID: 202
Type: IP (0x0800)
Internet Protocol, Src: 220.127.116.11 (18.104.22.168), Dst: 22.214.171.124 (126.96.36.199)
Header length: 20 bytes
Many thx indeed all :)
Pls refer to the post from Narayan which is excellent below:-
" When you enable voice vlan, a special-case 802.1Q trunk automatically is enabled through a CDP information exchange between the switch and the IP Phone. The trunk contains only two VLANs a voice VLAN (tagged VVID) and the data VLAN. The switch port's access VLAN is used as the data VLAN that carries packets to and from a PC that is connected to the phone's PC port. "