From: Alan Ewer (acewer64@gmail.com)
Date: Mon Jun 25 2007 - 22:00:11 ART
Hi Guys..
So I think my misunderstanding relates to the term "native vlan" in relation
to an access port !
I am more familiar with he term native vlan when talking about dot1q
trunks... not access ports .. !!
So..
if the config is
Fas 0/1
switch access vlan 300
switch voice vlan dot1p
the native vlan is going to be Vlan300 ...true ?? and therefore the traffic
will transit the switch as vlan 300 ?
Regds
AlanE
Oz
On 6/26/07, Antonio Soares <amsoares@netcabo.pt> wrote:
>
>
> Here's a capture i made a few weeks ago:
>
> +++++++++++++++++++++++++++++++++++++++++
> Frame 3 (118 bytes on wire, 118 bytes captured)
> Ethernet II, Src: Cisco_f6:f1:65 (00:17:0e:f6:f1:65), Dst: Cisco_c3:0d:38
> (00:15:63:c3:0d:38)
> 802.1Q Virtual LAN
> 000. .... .... .... = Priority: 0
> ...0 .... .... .... = CFI: 0
> .... 0000 0000 0000 = ID: 0
> Type: IP (0x0800)
> Internet Protocol, Src: 192.168.100.100 (192.168.100.100), Dst:
> 192.168.100.1 (192.168.100.1)
> Internet Control Message Protocol
> +++++++++++++++++++++++++++++++++++++++++
>
> This was the Switch config:
>
> !
> interface GigabitEthernet0/48
> switchport access vlan 333
> switchport mode dynamic desirable
> switchport voice vlan dot1p
> mls qos trust device cisco-phone
> spanning-tree portfast
> !
>
> These were my comments to the behaviour i saw:
>
> Data traffic untagged in and out, Voice traffic untagged out, tagged in
> with
> VLAN ID=0; PING DATA=OK, PING VOICE=OK
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Scott Morris
> Sent: segunda-feira, 25 de Junho de 2007 13:57
> To: 'M S'; acewer64@gmail.com; ccielab@groupstudy.com
> Subject: RE: Voice Vlan 0 - DOT1P
>
> If there is no dot1q tag, there is no dot1p priority field!
>
>
> Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
> #153, CISSP, et al.
> CCSI/JNCI-M/JNCI-J
> VP - Technical Training - IPexpert, Inc.
> IPexpert Sr. Technical Instructor
>
> A Cisco Learning Partner - We Accept Learning Credits!
>
> smorris@ipexpert.com
>
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> http://www.ipexpert.com
>
> _____
>
> From: M S [mailto:michaelgstout@hotmail.com]
> Sent: Monday, June 25, 2007 12:08 AM
> To: smorris@ipexpert.com; acewer64@gmail.com; ccielab@groupstudy.com
> Subject: RE: Voice Vlan 0 - DOT1P
>
>
>
> I was looking at this today. Can you let me know if i have it backwards?
> The 802.1p tag contains vlan 0, which is the native vlan. but when you
> connect the cisco phone to the cisco switch a trunk is automatically
> formed.
> With switchport interface command switchport access vlan 5, wouldn't the
> data traffic be tagged with vlan 5 and the 802.1p traffic be placed into
> the
> native vlan (vlan0)?
>
> THank You.
>
>
>
>
> _____
>
> From: "Scott Morris" <smorris@ipexpert.com>
> Reply-To: "Scott Morris" <smorris@ipexpert.com>
> To: "'Alan Ewer'" <acewer64@gmail.com>, "'Cisco certification'"
> <ccielab@groupstudy.com>
> Subject: RE: Voice Vlan 0 - DOT1P
> Date: Sun, 24 Jun 2007 21:59:21 -0400
> If you search Cisco's website (or Google) you'll find lots of references
> for
> VLAN 0 in regards to Voice VLANs. Basically, this is a designation for
> untagged frames, which means whatever your trunk's native VLAN is set to
> in
> the dot1q trunk to an IP phone, that's what VLAN 0 represents.
>
> That'll also mean it's the same VLAN as your PC's data behind the phone,
> and
> I'll tell you that's generally not a good idea in deployments. But this
> is
> all about the lab. :)
>
> So how about changing your voice vlan to something other than the default
> command set!
>
> To an IP phone, you SHOULD be trunking. The general spec is voice is
> tagged
> (dot1q), PC data is untagged (access vlan AKA your trunk's native vlan,
> untagged).
>
> HTH,
>
>
> Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
> #153, CISSP, et al.
> CCSI/JNCI-M/JNCI-J
> VP - Technical Training - IPexpert, Inc.
> IPexpert Sr. Technical Instructor
>
> A Cisco Learning Partner - We Accept Learning Credits!
>
> smorris@ipexpert.com
>
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> http://www.ipexpert.com
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Alan
> Ewer
> Sent: Sunday, June 24, 2007 8:36 PM
> To: Cisco certification
> Subject: Voice Vlan 0 - DOT1P
>
> Hi all...
> sorry if this has been answered before.....
>
> I am playing around with voice vlans on 3550's
>
> When I invoke the "switch voice vlan dot1p" command I get a message
> referring to the voice VLAN being VLAN0, yet i cannot create/see VLAN 0
>
> So where is this mystical VLAN ? How do I use it and why is the voice
> traffic there ?? I would have thought that i would put it on the default
> native vlan for the interface (usually vlan 1) .....as usual the Cisco
> doco
> is unhelpful..and to some extent confusing (to me at least)...
>
> Also if voice vlan is 0 and access vlan is 1, doesnt this imply that the
> port is also trunking ??
>
>
> any explanation gratefully accepted..
>
> Regds
> AlanE
>
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