Hi Aaron,

Do you consider what you have done a fix, or a potential work around that
may have customer implications? That may mean your customer now has partial
connectivity through the SP cloud - It may be that your customer is already
performing dot1q tunnelling and performing L2 protocol tunnelling (hence the
use of the "special multicast mac") - it may be better to talk to the
customer and verify what they are doing is within the service agreement of
the product/service you are supporting.  Interfaces that enter err-disable
state are trying to protect the network which is providing shared
infrastructure to multiple customers at the cost of service availability to
a single interface.   If they are doing qinq internally and using l2protocol
tunnelling, it may be simply a matter of them forgetting to put the
l2protocol tunnelling config so they decapsulate the STP/VTP/CDP/etc frames
before sending them on to you..

MPLS based Carrier Ethernet is what Service Providers these days are tending
to head towards in order to deal with large scale ethernet networks, it has
more scalability and more resilience than a native STP implementation.
Within the data centre though, Data Center Bridging which is somewhat IS-IS
based L2 routing/bridging mechanim is another technique that SPs are looking
at.

On Sun, Aug 15, 2010 at 1:00 AM, Aaron Moreck <[email protected]> wrote:

> I was having a bit of an issue with dot1q-in-q  and  l2 protocol tunneling
> where nterfaces were going err-disabled.
>
> I understand now (and I stresss the word now)  that if a packet with the
> special multicast mac address used for tunneling  is recieved on an
> interface configured for l2 protocol tunneling it will go err-disabled.
>
> The fix for this is to restrict specific VLANS  on the trunks.
>
> However, I found this easier said than done (especially if this was a large
> service provider network).  I have to admit that this is the very first time
> playing with dot1q-in-q tunneling so i am hoping some of you guys have been
> there and done that so to speak.
>
> Is there any debug command or show command that can help me determine what
> VLAN is causing the issue to make it easier to track down?
>
>
> Thanks
>
> Aaron
>
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