[c-nsp] Data VLAN/Voice VLAN

Clue Store cluestore at gmail.com
Sun Aug 30 03:45:29 EDT 2009


What platform/IOS are you running??

I think the older 3500xl PoE switch had to be in trunk mode to accomplish
the dot1(p)(q) header info so trust the EF marking of the packet
would work due to CDP improvements and working without actually having a it
in "trunk mode". Think newer platforms and IOS, CDP does the magic of the
headers of the aux vlan (which is the voice vlan) if im not mitaken. And u
can just use voice vlan and access mode and it works.

So no need to trunk on newer gear. But Pete's correct, u have the switchport
"mode" in access. And u might have to trunk depending on ur setup. Also
having it tagging "native" is useless in access mode.

HTH,
Clue

On Fri, Aug 28, 2009 at 6:52 PM, Bill Blackford <BBlackford at nwresd.k12.or.us
> wrote:

> If you are using 3560's, this has been my experience as well. If you are
> unfortunate enough to be using 3550XL's, then the whole game is different.
>
> The 3550XL way:
>
> interface FastEthernet0/5
>  switchport trunk encapsulation dot1q
>  switchport trunk native vlan 68
>  switchport mode trunk
>  switchport voice vlan 66
>  switchport priority extend cos 0
>  spanning-tree portfast
>
> The data vlan has to be indicated as native.
>
> Again, this has been my experience.
>
> -b
>
>
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:
> cisco-nsp-bounces at puck.nether.net] On Behalf Of Peter Rathlev
> Sent: Friday, August 28, 2009 3:44 PM
> To: Yuri Bank
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Data VLAN/Voice VLAN
>
> On Fri, 2009-08-28 at 15:20 -0700, Yuri Bank wrote:
> > interface FastEthernet0/4
> >  description phone
> >  switchport access vlan 77
> >  switchport trunk native vlan 55
> >  switchport mode access
> >  switchport voice vlan 66
> >
> > In this configuration, data is placed on vlan 55? From what I've read
> > on other forums and such is that the data would be on the configured
> > access vlan ( 77 ). Unfortunately I do not have an iphone to test
> > this. Could anyone give me some clarity?
>
> Untagged traffic on the port would be VLAN 77, since this is what you
> configured at access VLAN and since the port is in forced access mode.
>
> A compatible device (i.e. one the presents itself as a phone via CDP)
> would activate the voice VLAN and thus allow tagged incoming traffic on
> VLAN 66. This requires the switch (and port) to have CDP enabled by the
> way.
>
> The trunk configuration is ignored when you issue "switchport mode
> access".
>
> If you only need a stand-alone phone you can just use a simple access
> port in the voice VLAN.
>
> Regards,
> Peter
>
>
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