From: Chris (clarson52@comcast.net)
Date: Mon Oct 07 2002 - 07:32:06 GMT-3
Thanks for the clarification.
----- Original Message -----
From: "P729" <p729@cox.net>
To: "Chris" <clarson52@comcast.net>; "ccielab" <ccielab@groupstudy.com>
Sent: Sunday, October 06, 2002 10:15 PM
Subject: Re: 802.1q native vlan
> "This would also mean that it is restricted to the native vlan then right?
> Without a tag it could not be forwarded to any other vlan."
>
> The tagging mechanism is simply for differentiating traffic belonging to
> different VLANs across a given trunk. All VLANs can be tagged, while a
> maximum of one can be untagged. The untagged traffic is plain-old Ethernet
> traffic--there is nothing distinguishing about it. Only the switches
making
> up the endpoints of the trunk give significance to the untagged traffic
and
> assign it to the VLAN designated as the "native VLAN." The traffic for
each
> VLAN is switched normally, regardless of whether the traffic was tagged or
> untagged across the trunk. All that matters is the switch can
differentiate
> between the different VLANs on the trunk.
>
> That being said, there are other things to ponder. Since VLAN 1 is
> well-known as the default VLAN, there could be security implications for
> hosts left in this VLAN, such as one-way DoS attacks. Certain switches,
such
> as the Catalyst 4000, process switch untagged traffic, causing additional
> overhead (I'm sure there are others).
>
> Regards,
>
> Mas Kato
> https://ecardfile.com/id/mkato
> ----- Original Message -----
> From: "Chris" <clarson52@comcast.net>
> To: "P729" <p729@cox.net>; "chenyan" <chenyan@deeptht.com.cn>; "ccielab"
> <ccielab@groupstudy.com>
> Sent: Sunday, October 06, 2002 12:12 PM
> Subject: Re: 802.1q native vlan
>
>
> I have been looking through the Docs and indeed it does say that native
> vlan traffic is not tagged. I guess I have missed that when reading the
> switching docs previously, and was always taught that all traffic is
tagged.
>
> Thanks for the clarification.
>
> This would also mean that it is restricted to the native vlan then right?
> Without a tag it could not be forwarded to any other vlan.
>
>
>
> ----- Original Message -----
> From: "P729" <p729@cox.net>
> To: "Chris" <clarson52@comcast.net>; "chenyan" <chenyan@deeptht.com.cn>;
> "ccielab" <ccielab@groupstudy.com>
> Sent: Sunday, October 06, 2002 2:05 PM
> Subject: Re: 802.1q native vlan
>
>
> > "Any untagged frames will get tagged..."
> >
> > Mmmm...sounds kinda contradictory doesn't it? Actually, frames assigned
to
> > the native VLAN of the trunk are sent untagged across the trunk, period.
> But
> > one might ask, "how would the switches on each end know when there's a
> > native VLAN mismatch?" The answer for Cisco switches is through CDP. If
> CDP
> > is disabled or not available, then they wouldn't know and you can pretty
> > much bridge the two VLANs together and maybe not know it...
> >
> > Regards,
> >
> > Mas Kato
> > https://ecardfile.com/id/mkato
> > ----- Original Message -----
> > From: "Chris" <clarson52@comcast.net>
> > To: "chenyan" <chenyan@deeptht.com.cn>; "ccielab"
<ccielab@groupstudy.com>
> > Sent: Sunday, October 06, 2002 9:48 AM
> > Subject: Re: 802.1q native vlan
> >
> >
> > Any untagged frames will get tagged to the native vlan and travel the
> native
> > vlan.
> >
> >
> > ----- Original Message -----
> > From: "chenyan" <chenyan@deeptht.com.cn>
> > To: "ccielab" <ccielab@groupstudy.com>
> > Sent: Sunday, October 06, 2002 11:13 AM
> > Subject: 802.1q native vlan
> >
> >
> > > hi,guys
> > >
> > > I want to know why there is native vlan for 802.1q and what is that
for?
> > >
> > > Thanks
This archive was generated by hypermail 2.1.4 : Tue Nov 05 2002 - 08:35:41 GMT-3