From: David Pues \(dpues\) (dpues@cisco.com)
Date: Tue Nov 02 2004 - 13:47:35 GMT-3
It all depends on the type of switch used. Basically a trunk is NOT a
requirement between the IP phone and the switch except eg for a switch
module in a router.
The voice vlan config is basically there to let the phone know via CDP
how to tag the packets it sends (originated from the phone). At that
moment the phone will just pick this up via CDP and when ever it sends a
packet, it will tag it. The way Cisco has implemented this does not
require a trunk to be there (with the above exception). In this mode,
the switch will also not tag any packets out the port, which is not
required as the phone just looks at the destination MAC address and only
sends these packets to its logic (phone does MAC filtering). It does not
really look at the tags.
The voice vlan has a significance upstream to the network, not
downstream to the phone/pc.
Eg on a Cat4k, cat6k, cat3550 etc, putting the port in access mode into
the data vlan and assigning the voice/auxiliary vlan should do the
trick.
When you do configure a .1Q trunk, make sure to configure the data vlan
for the pc as the native vlan (as the phone just forwards the packets
which are not destined for the phone logic, without untagging the
packet) unless the daisy-chained device understands the tags....
So, Ahmed, native vlans are used when trunking and makes sure that the
data packets are untagged; access vlan is used in access mode.
My 2 cents,
David - CCIE 9666
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brian McGahan
Sent: Tuesday, November 02, 2004 5:29 PM
To: reo@chavallos.net; ccielab@groupstudy.com
Subject: RE: voice Vlan
You cannot issue the "switchport mode access" command on the
interface otherwise trunking negotiation cannot occur.
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> reo@chavallos.net
> Sent: Tuesday, November 02, 2004 9:51 AM
> To: ccielab@groupstudy.com
> Subject: Re: voice Vlan
>
> Here's an example
>
> ---
> interface GigabitEthernet1/2
> no ip address
> switchport
> switchport access vlan 30
> switchport mode access
> switchport voice vlan 130
> ---
>
> ----- Original Message -----
> From: "Ahmed Hassan" <ahmed_hassan@rayatelecom.net>
> To: <ccielab@groupstudy.com>
> Sent: Tuesday, November 02, 2004 1:01 AM
> Subject: voice Vlan
>
>
> > HI,
> > When we configure a port with the command Switchport voice Vlan 20
> >
> > How we configure the data VLAN on the same port
> >
> > Switchport access vlan 10
> >
> > Or
> >
> > Switchport native vlan 10
> >
> > Or Both
> > Switchport access vlan 10
> > Switchport native vlan 10
> >
> > Best Regards
> > Ahmed Hassan
> > Product Development Supervisor
> > Raya Telecom
> >
> >
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