RE: Native Vlan

From: Jared Scrivener (jscrivener@ipexpert.com)
Date: Sun Feb 22 2009 - 14:15:56 ARST

Always happy to help, Nadeem. J

 

Cheers,

 

Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP

Technical Instructor - IPexpert, Inc.

Telephone: +1.810.326.1444

Fax: +1.810.454.0130

Mailto: <mailto:jscrivener@ipexpert.com> jscrivener@ipexpert.com

From: Nadeem Ansari [mailto:nadeem.ansari574@gmail.com]
Sent: Sunday, 22 February 2009 11:07 AM
To: jscrivener@ipexpert.com
Cc: khurram noor; Cisco certification
Subject: Re: Native Vlan

 

Thanx for your quick reply Jared :)

On Sun, Feb 22, 2009 at 9:32 PM, Jared Scrivener <jscrivener@ipexpert.com>
wrote:

The tag will be a Dot1Q tag for VLAN1 when it is sent out. When it is
received, the trunk port removes the tag (as normal). A tag is only added
again if the receiving switch is sending tagged frames for the same native
VLAN (VLAN1) on another interface or if it is sending out a different trunk
port with a different native VLAN.

 

If the native VLAN was not VLAN1 but a different VLAN (VLAN2 for example),
then the tag will be for VLAN2. On the receiving switch's trunk port that
tag is removed and only added again if it needs to be forwarded via a trunk
port that tags VLAN2.

 

Cheers,

 

Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP

Technical Instructor - IPexpert, Inc.

Telephone: +1.810.326.1444

Fax: +1.810.454.0130

Mailto: <mailto:jscrivener@ipexpert.com> jscrivener@ipexpert.com

From: Nadeem Ansari [mailto:nadeem.ansari574@gmail.com]
Sent: Sunday, 22 February 2009 10:55 AM
To: Jared Scrivener
Cc: khurram noor; Cisco certification
Subject: Re: Native Vlan

 

My question is that what will be the tag on native vlan1 frame ?
What will be the case if we use some other vlan except vlan1 in this
scenario

Regard
Nadeem

On Sun, Feb 22, 2009 at 8:15 PM, Jared Scrivener <jscrivener@ipexpert.com>
wrote:

Hey Khurrum,

The other switch (that isn't tagging the native VLAN) will just remove the
tag and forward the traffic to any ports in that VLAN (VLAN 1 in your
example).

Cheers,

Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
Technical Instructor - IPexpert, Inc.
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
Mailto: jscrivener@ipexpert.com

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
khurram noor
Sent: Sunday, 22 February 2009 6:27 AM
To: Cisco certification
Subject: Native Vlan

Hello everyone.
I have a question ! I went across a scenerio which i wasnt able to fully
understand. in this scenerio i was asked to form 802.1q trunking among 4
switches, which by default has native vlan 1 as untagged. there was a
requirement that one of the switch should tag the native vlan 1 and others
should not. i did this and it was working. what i want to ask is if i
perform tagging on native vlan, is this not going to matter for switches
that are having untagged native vlan? what will happen in the background
when a switch recieves a tagged native vlan frames, which is not tagging
native vlan.

Any ideas? 

--
Khurram Noor
CCIP, CCNA

Blogs and organic groups at http://www.ccie.net

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