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I've have a scenario where a cisco switch is being connected to a
switch that doesn't support Vlans. That 2nd switch is sending frames
without vlan tags and I want them to be placed into vlan 801. My
thoughts are that the config to do this would simply be

switchport access vlan 801
switchport mode access

but I've seen a coworker use the config below

switchport access vlan 801
switchport trunk native vlan 801
switchport mode access

I know that the middle line changes the native vlan on a trunk port to
801, but why would you do this on an access port? It was my
understanding that on an acess port the switch wiill insert a Vlan 801
tag into any frames it recieves on that port. I guess my question is
what affect does chaning the native vlan on an access port have? Does
it place any untagged frames into vlan 801? If that's the case why
doesn't just making it an access port work. No joy on checking
command references only for switchport trun native vlan

On 2009-08-12, Dedan <> wrote:
> I've have a scenario where a cisco switch is being connected to a
> switch that doesn't support Vlans. That 2nd switch is sending frames
> without vlan tags and I want them to be placed into vlan 801. My
> thoughts are that the config to do this would simply be
>
> switchport access vlan 801
> switchport mode access
>
> but I've seen a coworker use the config below
>
> switchport access vlan 801
> switchport trunk native vlan 801
> switchport mode access
>
> I know that the middle line changes the native vlan on a trunk port to
> 801, but why would you do this on an access port? It was my
> understanding that on an acess port the switch wiill insert a Vlan 801
> tag into any frames it recieves on that port. I guess my question is
> what affect does chaning the native vlan on an access port have? Does
> it place any untagged frames into vlan 801? If that's the case why
> doesn't just making it an access port work. No joy on checking
> command references only for switchport trun native vlan

In the above configuration the "switchport trunk native" command is
ignored. It will only be used if you switch over to "switchport mode
trunk".

Ignoring VTP and CDP, the following two configurations would have the
same effect:

switchport mode access
switchport access vlan 801

is similar to

switchport mode trunk
switchport trunk native vlan 801
switchport trunk allow vlan 801

Hope this clears it up and doesn't confuse you even more

Thanks. I'd figured that was the case but was having trouble
convincing myself.