CCNP Voice Vlan question

[norteldude78]

Can someone tell me the difference between the two commands:

switchport voice vlan none
switchport voice vlan untagged

They seem to do the same thing. I also think the Cisco Press book might be wrong in that it says "switchport voice vlan untagged" carries the CoS in 802.1p bits (page 364, figure 14-2). I think untagged means the switch should treat voice and data the same, no 802.1p involved...

Anyone seen this?

 

[Jsteve]

none—Allow the IP phone to use its own configuration to send untagged voice traffic.

untagged—Configure the phone to send untagged voice traffic.

You can configure a port connected to the Cisco IP Phone to send CDP packets to the phone to configure the way in which the phone sends voice traffic. The phone can carry voice traffic in IEEE 802.1Q frames for a specified voice VLAN with a Layer 2 CoS value. It can use IEEE 802.1p priority tagging to give voice traffic a higher priority and forward all voice traffic through the native (access) VLAN. The IP phone can also send untagged voice traffic or use its own configuration to send voice traffic in the access VLAN. In all configurations, the voice traffic carries a Layer 3 IP precedence value (the default is 5).