From: M S (michaelgstout@hotmail.com)
Date: Mon Jun 25 2007 - 01:07:37 ART
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!
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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