From: Lee Donald (Lee.Donald@t-systems.co.uk)
Date: Fri Dec 10 2004 - 05:55:44 GMT-3
The management vlan can be changed, and Cisco encourage you to do so.
It is a good idea to change the default vlan 1, because of security. A new
switch could over write your vlan info when brought up etc.
-----Original Message-----
From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]
Sent: 09 December 2004 22:37
To: ccie2be; Keane, James; ccielab@groupstudy.com
Subject: RE: 3550 - Default Vlan - Native Vlan & Trunks
> Now, the default vlan. This, by default, is vlan 1 and I don't think
you
> can change that. This is the vlan over which the vtp and stp messages
> travel. And, from what I understand, even when this vlan isn't
allowed
> over
> a trunk, the vtp and stp traffic still goes over the trunk. Only the
user
> data from vlan 1 doesn't go over the trunk.
Correct. This is known as "VLAN 1 Minimization". When VLAN 1 is
removed from a trunk link, only normal user traffic in VLAN 1 is
removed. Necessary network traffic such as VTP and STP BPDUs still use
VLAN 1 for transmission between connected neighbors.
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> ccie2be
> Sent: Thursday, December 09, 2004 3:42 PM
> To: Keane, James; ccielab@groupstudy.com
> Subject: Re: 3550 - Default Vlan - Native Vlan & Trunks
>
> James,
>
> I think the issue you raise is the cause of great confusion to many
> people.
> But, the issue I think is one primarily of terminology.
>
> the native and default vlan's refer to different unrelated vlan's and
have
> different purposes for existing.
>
> The native vlan is only relevant to 802.1q trunks and has nothing to
do
> with
> anything else. As you probably know, a packet crossing a 802.1q trunk
> will
> have a vlan tag or it won't. If the packet doesn't have a vlan tag,
how
> does the switch know what to do with the packet? The answer is the
switch
> assume the packet is part of the native vlan and switches the packet
> accordingly. Which vlan is the native vlan? Whichever vlan YOU make
the
> native vlan. If you don't explicitly make any vlan the native vlan,
the
> default vlan is the native vlan.
>
> Now, the default vlan. This, by default, is vlan 1 and I don't think
you
> can change that. This is the vlan over which the vtp and stp messages
> travel. And, from what I understand, even when this vlan isn't
allowed
> over
> a trunk, the vtp and stp traffic still goes over the trunk. Only the
user
> data from vlan 1 doesn't go over the trunk.
>
> If I'm wrong with anything I've said, hopefully, someone will let us
know.
>
> HTH, Tim
>
>
> ----- Original Message -----
> From: "Keane, James" <James.Keane@agriculture.gov.ie>
> To: <ccielab@groupstudy.com>
> Sent: Thursday, December 09, 2004 11:11 AM
> Subject: 3550 - Default Vlan - Native Vlan & Trunks
>
>
> > I was asked a fairly straightforward question yesterday
> >
> > quote
> >
> > 'let's say you are only allowed to send odd
> > VLANs, 3,5,7,9,11, over a trunk, how about the default VLAN ? I
think
> you
> cannot disallow the default VLAN 1 unless you set the native VLAN to
> > something else, is that right ?'
> >
> > unquote
> >
> > I responded with sure you cant disable the vlan you are trunking on
..
> but
> I'll just verify that in the lab...
> >
> >
> > To my astonishment I was able to completely remove vlan 1 from the
trunk
> while keeping my native vlan as 1..
> >
> > now the trunk mode on one side reads 'n-802.1q' and '802.1q' on the
> other.
> Not quite sure what the n-802.1q is all about ??!
> >
> > What is going on ?
> >
> > One more final thing is buggin me - the default vlan is one and the
> native
> vlan is one - you can change the native ...
> >
> > ... can you change the default ???
> >
> >
> >
> > I thought I understood this topic (grrrr)
> >
> >
> > Any light on this would be greatly appreciated
> >
> >
> > I am going back to practical studies II to revise the basics !!!
> >
> >
> > Regards,
> >
> > James Keane
> >
> >
> >
**********************************************************************
> > *********** Department of Agriculture and Food ***************
> >
> > The information contained in this email and in any
> > attachments is confidential and is designated solely
> > for the attention and use of the intended recipient(s).
> > This information may be subject to legal and professional
> > privilege. If you are not an intended recipient of
> > this email, you must not use, disclose, copy,
> > distribute or retain this message or any part of it.
> > If you have received this email in error, please
> > notify the sender immediately and delete all copies of
> > this email from your computer system(s).
> >
**********************************************************************
> >
> >
This archive was generated by hypermail 2.1.4 : Mon Jan 03 2005 - 10:31:26 GMT-3