[c-nsp] Spantree .1Q packets received on non-trunk port.

[Mike Hale]

"when the handoff is an access port"
Because I don't think it's actually configured as an access port.  The
behavior of the interface mimics exactly what you had to configure on
yours...that is, a trunk port with a native VLAN defined.

If the configuration is what I think it is, the reason the tech's
equipment functioned the way it did was two fold.  First, the gear
didn't care about STP packets.  So when configured as an access port,
the test gear sent untagged packets onto the interface which the
upstream provider's switch put into VLAN 638 (because their interface
had 638 configured as a native vlan).  The reason it didn't work when
configured as a trunk is because the device didn't have the native
vlan configured.  So it tried to send packets, tagged with VLAN 638;
this failed because the default behavior on the Cisco gear I've worked
with is to drop packets that are tagged with the native VLAN.

"Aren't BPDU's normally part of STP's chatter?"
Yes, but in my experience BPDUs are only sent on 'infrastructure'
ports.  That is, ports that are trunked or have special STP settings
applied for uplinks.  Access ports die (as the OP experienced) when
they notice STP packets in order to prevent a loop.


On Tue, Aug 26, 2014 at 7:55 PM, Brielle Bruns <bruns at 2mbit.com> wrote:
> On 8/26/14 7:34 PM, Lee Starnes wrote:
>>
>> Thanks Mike.
>>
>> That took care of the problem, but still not sure why I would have to set
>> the port up as a trunk port when the handoff is an access port. When the
>> carrier tested the port, they tested it as an access port and then tried
>> to
>> test it as a trunk port and their test set failed when in trunk mode. Very
>> odd.
>>
>> Anyway, thanks again.
>>
>
>
> Aren't BPDU's normally part of STP's chatter?
>
> I get errors like that when my MSTP instance settings are mismatched between
> switches.   Perhaps its a mix of issues.
>
>
> --
> Brielle Bruns
> The Summit Open Source Development Group
> http://www.sosdg.org    /     http://www.ahbl.org
>
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