Re: dot1q tag native & sh int switchport

Depends on a platform, on 6500/4500 there would be a reason since it
supports per switchport native VLAN tagging disabling with interface
command "no switchport trunk native vlan tag".
http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/dot1qtnl.html#wp1006255

I'd put it this way; "show interface switchport" for 3560/3750 platforms
has some misleading/missing lines. Since this is a minor disadvantage
and there is a way to verify what actually is happening, it has probably
escaped quality assurance testers' attention. Another possible reason
for having "Administrative" for this as enabled might be in original
idea of having a global "vlan do1q tag native" enabled by default which
didn't happen.

If you are so keen on finding the real one, you can try and open P4 case
with TAC, we'd love to hear the story. :-)

A.

Keegan.Holley_at_sungard.com wrote:
>
> Well, native vlan tagging is administratively disabled, but it still
> shows up as enabled in the sh int switchport. Also, there no
> operational status entry. Lastly, native vlan tagging isn't
> negotiated so there would be no reason for the operational and
> administrative modes to differ.
>
> RSRack1SW1#sh vlan dot1q tag native
> dot1q native vlan tagging is disabled
>
> RSRack1SW1#sh int g0/13 sw
> RSRack1SW1#sh int g0/13 switchport
> Name: Gi0/13
> Switchport: Enabled
> Administrative Mode: trunk
> Operational Mode: trunk
> Administrative Trunking Encapsulation: dot1q
> Operational Trunking Encapsulation: dot1q
> Negotiation of Trunking: On
> Access Mode VLAN: 1 (default)
> Trunking Native Mode VLAN: 46 (VLAN_46)
> Administrative Native VLAN tagging: enabled
>
>
>
>
>
>
> *Re: dot1q tag native & sh int switchport*
>
>
> *Alexei Monastyrnyi * to: Keegan.Holley
> 07/14/09 08:38 PM
>
>
> Cc: Group study
>
>
> *Please respond to alexeim73*
>
>
>
>
> ------------------------------------------------------------------------
>
>
>
> I think "Administrative" means the state the port was administered to be
> or start from by configuration commands, Some one can probably correct
> me on that.
>
> Like in this quick example below.
>
> Fa0/1 is configured for switcport mode "dynamic desirable" and there is
> no such thing for operational mode, it would be either trunk or access
> port. So here we go, observing how Administrative Mode changes as we
> change a switchport configuration.
>
> SW1#sh run in fa 0/1
> Building configuration...
>
> Current configuration : 105 bytes
> !
> interface FastEthernet0/1
> description R1 eth 0/0
> switchport mode dynamic desirable
> duplex full
> end
>
> SW1#sh inter fa 0/1 swi
> Name: Fa0/1
> Switchport: Enabled
> Administrative Mode: dynamic desirable
> Operational Mode: static access
> [...]
>
>
> SW1#conf t
> Enter configuration commands, one per line. End with CNTL/Z.
> SW1(config)#in fa 0/1
> SW1(config-if)#sw mode acc
> SW1(config-if)#do sh run in fa 0/1
> Building configuration...
>
> Current configuration : 94 bytes
> !
> interface FastEthernet0/1
> description R1 eth 0/0
> switchport mode access
> duplex full
> end
>
>
> SW1(config-if)#do sh int fa 0/1 swi
> Name: Fa0/1
> Switchport: Enabled
> Administrative Mode: static access
> Operational Mode: static access
> [...]
>
> I think for tagging native VLAN "Operational Mode" is just missing for
> whatever reason. Might be interesting to file it as a fix request for
> the show command to TAC. :-)
>
> HTH
> A.
>
>
> Keegan.Holley_at_sungard.com wrote:
> >
> > Any idea what it does mean?
> >
> > Thanks for answering,
> >
> > Keegan
> >
> >
> >
> >
> >
> > *Re: dot1q tag native & sh int switchport*
> >
> >
> > *Alexei Monastyrnyi * to:
> Keegan.Holley
> > 07/14/09 07:20 PM
> >
> >
> > *Please respond to alexeim73*
> >
> >
> >
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> > Hi.
> > It doesn't really mean operational status of the switch-port for dot1q
> > native vlan tagging. On some platforms (like 6500) there is actually
> > "Operational Native VLAN Tagging: ... " line in "show interface
> > switchport" output which changes according to "vlan dot tag native"
> > presence in the ocnfig. So you'd better trust "show vlan dot tag antive"
> > output.
> >
> > HTH
> > A.
> >
> > Keegan.Holley_at_sungard.com wrote:
> > >
> > > No, acutally.
> > >
> > >
> > >
> > > *Re: dot1q tag native & sh int switchport*
> > >
> > >
> > > *Alexei Monastyrnyi * to:
> > Keegan.Holley
> > > 07/13/09 10:32 PM
> > >
> > >
> > > *Please respond to alexeim73*
> > >
> > >
> > >
> > >
> > >
> ------------------------------------------------------------------------
> > >
> > >
> > >
> > > haven't you got my replay mate/?
> > >
> > > Keegan.Holley_at_sungard.com wrote:
> > > > Sorry for the repost. Just wondering if no one saw it or no one
> > > knows the
> > > > answer.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > dot1q tag native & sh int switchport
> > > >
> > > > Keegan.Holley
> > > > to:
> > > > Cisco certification
> > > > 07/12/09 11:33 PM
> > > >
> > > >
> > > > Sent by:
> > > > nobody_at_groupstudy.com
> > > > Please respond to Keegan.Holley
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Does anyone know what the Administrative native vlan tagging line
> > > means in
> > > >
> > > > the show int switchport? It always says enabled even when
> native vlan
> > > > tagging is off.
> > > >
> > > > RSRack1SW2(config)#do sh int g0/16 swi
> > > > Name: Gi0/16
> > > > Switchport: Enabled
> > > > Administrative Mode: trunk
> > > > Operational Mode: trunk
> > > > Administrative Trunking Encapsulation: dot1q
> > > > Operational Trunking Encapsulation: dot1q
> > > > Negotiation of Trunking: On
> > > > Access Mode VLAN: 1 (default)
> > > > Trunking Native Mode VLAN: 46 (VLAN_46)
> > > > Administrative Native VLAN tagging: enabled
> > > > Voice VLAN: none
> > > >
> > > >
> > > > RSRack1SW2(config)#do sh vlan dot tag native
> > > > dot1q native vlan tagging is disabled
> > > > RSRack1SW2(config)#
> > > >
> > > >
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Received on Wed Jul 15 2009 - 12:06:39 ART