Re: Native Vlan Application

had a setup with DSL modems that connected to dot1q trunks, LAN was using
vlan1 for everything as in one subnet /20...

so wanted to break the network into vlans, but lost the ability to manage
the DSL modems over the trunks, so set the native vlan to match the
vlan/subnet that we used to manage the IP subnet on the DSL modems

basic idea if the diagram holds its form:

CORE_SW <- do1q trunk--> ethernet/DSL Modem/xdsl <----copper over campus
run-----> xdsl/DSL Modem/ethernet <---dot1q trunk--> Access_SW

CORE_SW to Access_SW was a do1q trunk, and the DSL Modems only had one
ethernet port for management IP and trunk traffic so needed untagged traffic
to stay in DSL Modem Management vlan...

hopefully that makes sense, but the object is the device in the middle of
the trunk sends/receives packets untagged because it doesn't understand the
dot1q tag...

--
Garry L. Baker
"There is no 'patch' for stupidity." - www.sqlsecurity.com
On Sun, Aug 8, 2010 at 4:40 AM, Asim Riaz <ariaz78_at_gmail.com> wrote:
> Hi List,
> I am sure this topic has discussed before, can someone give me application
> for the native vlan when using 802.1Q trunking?
>
> I know the theory that if an untag frame arrive on the trunk, it will be
> forwarded to native vlan, why would I need an untag frame when two of my
> interconnected switches speak 802.1Q and can forward traffic for the vlans
> across switch boundaries?
>
>
>
> Thanks
>
> Asim
>
>
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