[c-nsp] Voice VLAN Question - QOS

[Tim Jackson]

That's partially correct.. Usually IP phones tag the voice traffic and pass
through any data from the switch in the phone as untagged... So you would
need to either configure as follows:

int fa0/8
 descr xxxx
 switchport mode access
 switchport access vlan 101
 switchport voice vlan 102
!

That usually will work for any Polycom/Cisco phone w/ CDP enabled (using CDP
to discover the VLAN to tag voice on as well)... It should work for non-CDP
enabled phones (I've had mixed success with this on different platforms), so
you may have to configure it:

int fa0/8
 descr xxxx
 switchport mode trunk
 switchport trunk allowed vlan 101,102
 switchport trunk native vlan 101
!

The other thing that we always did here, was to enable "mls trust cos" and
all of the IP phones set CoS5 on the tagged traffic (not positive about your
phones, polycom and cisco both do if configured)..

--
Tim

On 1/26/07, Paul Stewart <paul at paulstewart.org> wrote:
>
> Hi there...
>
> We have a network of about 60-65 desktops and each one now has an IP phone
> (mixture of phones - mainly Snom and Aastra) ... we I've been researching
> the Voice VLAN option as a possible QOS enhancement...
>
> I've configured a test port like this:
>
> interface FastEthernet0/8
> description xxxxxxxxx
> switchport trunk allowed vlan 101,102
> switchport mode trunk
> switchport voice vlan 102
> switchport priority extend cos 5
> spanning-tree portfast
>
>
> VLAN 101 is data and VLAN 102 is voice ...
>
> Is this the correct way to do it?  Does my configuration above make cos 0
> for data and cos 5 for voice automatically without honouring whatever the
> phone defaults to?
>
> On the trunk ports between switches how do I make sure cos 5 gets passed
> through?
>
> Finally, when it reaches the switch facing our Cisco ASA it's broken into
> ports (one for data and one for voice) - is there a way to flag cos=5 for
> everything off a port?  I've opened a ticket at Cisco to understand how
> the
> ASA handles cos values... they have told me so far that it just passes
> through without any configuration required but I'm thinking there must be
> more to it...;)
>
> Sorry for all the questions... been reading a lot on this and want to make
> sure my reading = good configuration..
>
> Paul
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>