Re: VLAN 1 - Native

[Eric Dumazet <eric.dumazet@xxxxxxxxx>]

Le mercredi 01 février 2012 à 09:57 -0500, yao zhao a écrit :
> On Wed, Feb 1, 2012 at 9:50 AM, yao zhao <yao.development@xxxxxxxxx> wrote:
> >
> >
> > On Wed, Feb 1, 2012 at 8:04 AM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> >>
> >> Le mercredi 01 février 2012 à 11:24 +0000, Leonardo Uzcudun a écrit :
> >> > ________________________________
> >> > Da: Leonardo Uzcudun <uzcudunl@xxxxxxxx>
> >> > A: "netdev@xxxxxxxxxxxxxxx" <netdev@xxxxxxxxxxxxxxx>
> >> > Inviato: Mercoledì 1 Febbraio 2012 12:22
> >> > Oggetto: VLAN 1 - Native
> >> >
> >> > Hello:
> >> >
> >> > I'm connecting my Linux computer (debian 2.6.32-5) to a switch to
> >> > implement vlans.
> >> >
> >> > All is working fine except for the VLAN 1. Of sure you are aware of
> >> > this situation and i would like to knoe if there is any parameter or
> >> > setting that i should set in the vlan (linux side, not switch)
> >> > configuration. Here's my configuration:
> >> > ip addr add 0.0.0.0 dev eth0
> >> > ip link set eth0 up
> >> > ip link add link eth0 name eth0.1 type vlan id 1
> >> > ip link add link eth0 name eth0.101 type vlan id 101
> >> > ip addr add 0.0.0.0 dev eth0.1
> >> > ip addr add 0.0.0.0 dev eth0.101
> >> > ip link set eth0.101 up
> >> > ip link set eth0.1 up
> >> > brctl addbr br_vlan_1
> >> > brctl addbr br_vlan_101
> >> > brctl addif br_vlan_1 eth0.1
> >> > brctl addif br_vlan_101 eth0.101
> >> > ip addr add 0.0.0.0 dev br_vlan_1
> >> > ip
> >> > addr add 0.0.0.0 dev br_vlan_101
> >> > ip link set br_vlan_1 up
> >> > ip link set br_vlan_101 up
> >> >
> >> > Traffic on vlan 101 is working fine. Traffic on VLAN 1 is not working
> >> > cause the packets are going out from eth0 like tagged. How could i set
> >> > the VID 1 as untagged?
> >>
> >> What do you mean by "sending packets for VID 1, untagged " ?
> >>
>  on switch like Cisco: vlan 1 is the native vlan or default vlan so it is
>  untagged. untagged means packet has no vlan header.
> 
> >>
> >> What is the difference between vlan 101 and vlan 1 ?
> 
>  No other difference. Just because it is vlan 1  which is special in
>  switches(of course it can be changed on switch side but he doesn't want to)

VID=1 is not the "known" native vlan at all, this is a vendor (stupid ?)
extension.

There is no ID reserved to untagged traffic in the 802.1Q specs, since
by definition, if traffic is untagged, there is _no_ VLAN tag in the
frame.

Untagged traffic on linux is on eth0 itself (ingress or egress), not on
eth0.xxx




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